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Bill Fitzmaurice - Omnitop 12s (built by Insomnia)

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Topic: Bill Fitzmaurice - Omnitop 12s (built by Insomnia)
Posted By: Disco Stu
Subject: Bill Fitzmaurice - Omnitop 12s (built by Insomnia)
Date Posted: 10 April 2008 at 11:20pm
So, I posted a quick review over at BFM about these but just to show I havent been totally dead in the sound department the last couple of weeks have been spent wiring up and testing these puppies.









Whats inside?

P.Audio SN12MBs, 3x 1177 dual element Piezos per cab, cut and glued into a vertical array (you can see down the centre of each cab) wired in series (each piezo has the two elements in parallel). This gives equivalent to around 900W power handling for high end of each cab.

Now the P.Audio SN12MB drivers are not the recommended drivers for this cab, and I have already brought up this point on the BFM forum, they dont have the requisite rising response in the midrange.

HOWEVER this does not seem to affect the response very much and on the RTA, with very little effort I managed to get plenty in the 1-2kHz range out of them with no more than around 3dB of boost in that region in order to do so.

How do they sound?

Loud, a bit too loud for my lounge, as always I started off with the typical pink noise, and couldnt turn the amp up past about -18dB without feeling like donning some ear protection.

Calculating that back, thats 9W going in.... OUCH.

So I dont suppose I will have much trouble getting more than enough volume than I need for the future, and I am very glad I went with 4 singles rather than 2 doubles!

Since loud is about the least important spec for a discerning ear what can I say about them?

Well, the problems I thought I was going to have with the sound were likely to come in the midrange but they didnt, in fact I was very surprised at how smooth the crossover between the woofer and tweeters sounded.

HF sound is typical of a piezo, fairly bright but transients are largely good, the brightness can be controlled with a touch of EQ, and so the sound is actually pretty detailed.

I was a bit unsure of what was going on in the mids between 100-500Hz at first, but the drivers had not bedded in fully so this may explain it, as may the fact that the room was probably adding some colouration and cancellations to mess up what I was hearing.

After running a basic auto EQ I sat back and listened to several hours of different source material at a volume I could stand that didnt start to compress my ear drums.

Compared to the typical reflex cabs everybody is used to using, the first thing that jumps out at you when you listen to a horn is the lack of detail that reflex cabs can convey particularly in the lower mids. I much prefer the controlled punch in the lower mids that these cabs put out over a typical reflex.

For me during my listening sessions it allowed me to hear things in the music that I had never previously been aware of. I felt that the nodes in the room I was listening in were muddying up the sound below 100Hz, so I engaged the crossover at that frequency and did the bulk of my listening with the cab running over the intended range it will be used in and it did clear up a lot of the issues I was concerned about earlier on.

My source material consisted of a wide variety of music but I was always listening with reference to how well it performed on vocals and instruments since the majority of work I do is live band. One particular event struck me and that was upon listening to a Jeff Beck album, at the beginning of a track there is a loop he uses that obviously hadnt had its volume automated smoothly in the DAW because at the end of the loop as the sound died away, there was a jump between the acoustic silence and digital silence and I could actually hear where the loop points started and ended. I had never heard this before on this particular track so it was eye opening just how much detail horns can and do give, and especially ones that really cost this little to put together.

So after this I want to see how much detail horns can give on source material that I really knew well so I opened up the music collection and went through and sure enough it revealed a few other details in tracks that had previously been masked by a reflex.

So overall been quite impressed. Just good sounding cabs, not exceptional, but very useable with fairly minimal EQ and I expect FAR too loud to ever get close to their full capabilities.

Will add more details as I play out with them in different venues and work a bit more on the EQ settings.

Stu


-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches



Replies:
Posted By: mylesound
Date Posted: 11 April 2008 at 12:18am
Or stick a 2" compression driver in it and use 2 a side
i would expect it to only sound Better


Posted By: Jake_Fielder
Date Posted: 11 April 2008 at 9:11am

Stu, if i had one of these per-side (on top of a stereo stack) how much people would they cover (very roughly) also whats the dispertion like? they seem really good.



Posted By: Disco Stu
Date Posted: 11 April 2008 at 12:56pm
Originally posted by Jake_Fielder Jake_Fielder wrote:

Stu, if i had one of these per-side (on top of a stereo stack) how much people would they cover (very roughly) also whats the dispertion like? they seem really good.



Pass haven't had them out of the house at war volume yet.

Dont know exactly, I was sitting 30 degrees off axis when listening and it was ok, beyond about 45 degrees off axis it starts to degrade a bit but not as crazily as a reflex does.

Each cab is probably about 90H x 30V

Each cab is supposedly around 104dB sensitivity and with the recommended driver 250W power handling.

Punch those two together and you get a theoretical 128dB, take off 3dB or so for power compression - 125dB something like that.

All depends where you cross em over really, and how much bass and subbass you are running.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Strange Daze
Date Posted: 11 April 2008 at 1:31pm
they look great :)


Posted By: Disco Stu
Date Posted: 11 April 2008 at 4:05pm
Cheers, and cheers to Insomnia for making them so great, and markie for the grille obv.

Already managed to knock a chip of paint off carrying them through doorways, need to get some soft padded covers for them, keep phoning people but no-one is phoning back.

Anyone recommend a good place for cab covers?

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Jake_Fielder
Date Posted: 11 April 2008 at 4:21pm
Originally posted by Disco Stu Disco Stu wrote:

Originally posted by Jake_Fielder Jake_Fielder wrote:

Stu, if i had one of these per-side (on top of a stereo stack) how much people would they cover (very roughly) also whats the dispertion like? they seem really good.



Pass haven't had them out of the house at war volume yet.

Dont know exactly, I was sitting 30 degrees off axis when listening and it was ok, beyond about 45 degrees off axis it starts to degrade a bit but not as crazily as a reflex does.

Each cab is probably about 90H x 30V

Each cab is supposedly around 104dB sensitivity and with the recommended driver 250W power handling.

Punch those two together and you get a theoretical 128dB, take off 3dB or so for power compression - 125dB something like that.

All depends where you cross em over really, and how much bass and subbass you are running.
Stu
 
My aim is to have the ported horns i have designed on bass up to 180Hz then i want a midtop box to go on top. I recon i'd need two of my bass cabs per midtop, but once i have over 2 bass cabs perside i'll need more topend but it wont be tall enough to stack and i cant have two on a pole can I? and i assume i cant splay them - they need to be on top of each other with those peizos right?
 


Posted By: Disco Stu
Date Posted: 11 April 2008 at 5:33pm
Originally posted by Jake_Fielder Jake_Fielder wrote:


My aim is to have the ported horns i have designed on bass up to 180Hz then i want a midtop box to go on top. I recon i'd need two of my bass cabs per midtop, but once i have over 2 bass cabs perside i'll need more topend but it wont be tall enough to stack and i cant have two on a pole can I? and i assume i cant splay them - they need to be on top of each other with those peizos right?

 


1) Id see what they sound like before you look at 180Hz as a crossover point, I dont think anyone has had much success crossing a folded horn higher than 140Hz and the 2x12s of these will be very strong to that frequency, the 1x12s might get a bit overdriven under 200Hz if you drive them to hell, but the 2x Bass should give enough SPL to compensate for that.

2) You can have 2 cabs on a stand strapped together, I will be where necessary. They are very light, all Neo drivers and 12mm plywood, Easily a 1 handed lift.

3) I wouldn't recommend splaying any cabs unless they have very tight dispersion. With these being about 80-90H especially not. The HFs of the tweeters integrate better if you stack vertically. If the audience is close, which they can be in clubs or bars, crossfire the cabs, this doesnt necessarily require 2 stands, just get a T bar for your speaker stands and sit them side by side facing towards each other at 90 degrees.

If you can haul and know you can use 2x12s then I would go with them. I wasnt sure that I would need that much and so I went with the 4 singles instead. VERY glad I did so far.

I prefer to have a mid top that can go as low as possible to carry as much of the lead vocal without splitting it between two sources and getting an unbalanced level.

For DJ the situation may be different but I still like to carry the sounds that are not bass and kick through the mains rather than the subs.

Folds = filtering no matter how you look at it, thats why Bandpass cabs are best below 100Hz as well. Vocals through ports? Does a megaphone ring a bell?

Stu


-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Disco Stu
Date Posted: 11 April 2008 at 5:40pm
Originally posted by mylesound mylesound wrote:

Or stick a 2" compression driver in it and use 2 a side
i would expect it to only sound Better


I cant say one way or another but my experience of listening to 2" drivers generally is that they can take your head off at 50 paces but their general conveyance of detail isnt great, ask sukebe what he thinks of his, I think he has that exact setup.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Tony Wilkes
Date Posted: 11 April 2008 at 8:29pm
Originally posted by Disco Stu Disco Stu wrote:



Anyone recommend a good place for cab covers?

Stu


Stu,

http://www.proaudiocovers.co.uk/

Tony


Posted By: mylesound
Date Posted: 11 April 2008 at 9:49pm
Does BFM have anything with tighter dispersion the omnitop12 seems it might fit my need but the problem is i dont like the idea of going into a large outdoor event and standing up 12 ontop eachother perside(or could it be done?) if he has something with tighter disp. so i can splay 2 stacks of 6 that would be much better.
any input?


Posted By: Mark James
Date Posted: 11 April 2008 at 10:04pm
12 mid his?????? if you need that many id start thinking you want something a helluva lot louder with wider dispersion........
Ie maybey something with 3x15" low mid <300hz and 2x8" mid 300<2400hz
Ive not seen anything designed o use 6 per side except line array stuff.........


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If you want people to feel the bass then a reflex design is probably best as you get the most air movement per decibel from those.      errrrr yes wtf?


Posted By: jethrocker
Date Posted: 11 April 2008 at 10:24pm
Several of the Turbo top boxes are available in tight 20/25deg dispersion.. good for 4 a side and do-able with 6 I guess... 


Posted By: mylesound
Date Posted: 11 April 2008 at 10:34pm
I land up having local sounds provide a system in which i mix down
but even in this situation we end up lacking in the top end
16 TSW's tho


Posted By: Disco Stu
Date Posted: 11 April 2008 at 10:45pm
Why dont you crossfire then?

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Jake_Fielder
Date Posted: 14 April 2008 at 9:35am
Originally posted by Disco Stu Disco Stu wrote:

Originally posted by Jake_Fielder Jake_Fielder wrote:


My aim is to have the ported horns i have designed on bass up to 180Hz then i want a midtop box to go on top. I recon i'd need two of my bass cabs per midtop, but once i have over 2 bass cabs perside i'll need more topend but it wont be tall enough to stack and i cant have two on a pole can I? and i assume i cant splay them - they need to be on top of each other with those peizos right?

 


1) Id see what they sound like before you look at 180Hz as a crossover point, I dont think anyone has had much success crossing a folded horn higher than 140Hz and the 2x12s of these will be very strong to that frequency, the 1x12s might get a bit overdriven under 200Hz if you drive them to hell, but the 2x Bass should give enough SPL to compensate for that.

2) You can have 2 cabs on a stand strapped together, I will be where necessary. They are very light, all Neo drivers and 12mm plywood, Easily a 1 handed lift.

3) I wouldn't recommend splaying any cabs unless they have very tight dispersion. With these being about 80-90H especially not. The HFs of the tweeters integrate better if you stack vertically. If the audience is close, which they can be in clubs or bars, crossfire the cabs, this doesnt necessarily require 2 stands, just get a T bar for your speaker stands and sit them side by side facing towards each other at 90 degrees.

If you can haul and know you can use 2x12s then I would go with them. I wasnt sure that I would need that much and so I went with the 4 singles instead. VERY glad I did so far.

I prefer to have a mid top that can go as low as possible to carry as much of the lead vocal without splitting it between two sources and getting an unbalanced level.

For DJ the situation may be different but I still like to carry the sounds that are not bass and kick through the mains rather than the subs.

Folds = filtering no matter how you look at it, thats why Bandpass cabs are best below 100Hz as well. Vocals through ports? Does a megaphone ring a bell?

Stu
 
I wouldnt have thought vocals go down to 180Hz?
as 200Hz is a 171cm wavelength, and my horn is 85cm with one ~100 degree fold i thought it might be ok up that high...? but anyway this isnt the thread for talking about my design.
 
Those bill fitz cabs seem ok, i think i'll look into them further when im ready to look at mid/hi's, that will be a long thime though!


Posted By: Disco Stu
Date Posted: 14 April 2008 at 2:51pm
Originally posted by Jake_Fielder Jake_Fielder wrote:


I wouldnt have thought vocals go down to 180Hz?



as 200Hz is a 171cm wavelength, and my horn is 85cm with one ~100 degree fold i thought it might be ok up that high...? but anyway this isnt the thread for talking about my design.

 

Those bill fitz cabs seem ok, i think i'll look into them further when im ready to look at mid/hi's, that will be a long thime though!


Oops you would be wrong, very wrong, the lower end of the male vocal can go down to 80Hz or lower.
Check this out http://www.youtube.com/watch?v=ZzafJqw0xHw

The bass solo at 00:34 is a low F which is around 44Hz

The loud low B in this recording is around 70Hz. I can sing about 90Hz myself but not very loud.
http://www.youtube.com/watch?v=6WpD2Cspn6g

By not having this low range in the mid tops your mid tops can end up sounding thin. For a live vocal this can be terrible. For a recorded female vocal or high male vocal its usually ok, but this is why I bang on about having the vocals in the mid cab, which is up at head height.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Jake_Fielder
Date Posted: 14 April 2008 at 3:00pm
Its unrealistic to expect a raised mid cab to drop to 90Hz though, without being massive, and by dropping to 90Hz its not really a midcab anymore!
 
Whats the solution?


Posted By: Disco Stu
Date Posted: 14 April 2008 at 4:07pm
Originally posted by Jake_Fielder Jake_Fielder wrote:

Its unrealistic to expect a raised mid cab to drop to 90Hz though, without being massive, and by dropping to 90Hz its not really a midcab anymore!
 

Whats the solution?


The Xtro does
The DR250/280 do
Most arrays drop down to 100Hz.

But that is why I have problems with some other midcabs, because they just dont drop low enough to provide a useful crossover point to match with a 1 way bass cab.

The problem area is in cabs where a) the bass is not high enough to make ear level, hence the bottom of the vocal range is aurally separated from the tops. Having heard this phenomenon a lot I can tell you that I think it sounds awful.

If you have a bass stack thats high enough this is not so much of a problem since the mid tops sit on top of the stack and the upper bass cab is high enough that its at ear level. So if you do, probably no need to worry about it.

The solution for a lot of folks who dont run "stacks" they run subs together and then mid tops on sticks or stands, is to run the mid tops a little lower than they otherwise would, maybe down to 100Hz and then run the subs with a small overlap. The problems you get with frequency cancellation are less of a problem when the sources are separated.

For live work another alternative is aux fed subs.

Remember that crossover points are not absolute, if you have 100Hz crossover and 126dB of bass vs 120dB of midtop, with a 12dB slope, it will be 150Hz before the two levels even out.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Jake_Fielder
Date Posted: 14 April 2008 at 4:14pm
To be honest an Xtro is not the sort of thing i would like to be lifting onto a stand!
 
I will probably have a stack high enough to put midtops on eventually but i wouldnt want to have to use it all the time, i need a soloution for small gigs aswell. This is difficult!
 
(cheers for your helP)


Posted By: Disco Stu
Date Posted: 14 April 2008 at 4:17pm
Reflex then, less of an SPL jump at lower frequencies.

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Tony Insanity
Date Posted: 22 April 2008 at 8:51pm
Why piezo's? Smile

-------------
.....you might also look for her companion, a large Chinese rabbit, who is easy to spot since he is only standing on his hind feet in the shade of a cinnamon tree...


Posted By: Jake_Fielder
Date Posted: 22 April 2008 at 9:48pm
Check bill fitz forum, i think theres a thread explaining it.
 
Some people recon they're sh*t, some recon they're good when used right, i dont have an opinion as i havent heard them in this arrangement.
 
Billfitz likes to crossfire them and cuts the horn down to make the radiating elements closer for coupling.


Posted By: Disco Stu
Date Posted: 22 April 2008 at 11:13pm
Originally posted by Tony Insanity Tony Insanity wrote:

Why piezo's? Smile


Why not?

Before you ask, there have been pretty exhaustive tests made by myself and others on the BFM forum on Piezos. I personally listened to the different models to see which ones sound best on their own and in groups.

Others have tried Piezos vs compression drivers, and the result was that unless you pick a compression driver over at least £130, and couple it to an ideal horn, and then throw shedloads of EQ at it, a bank of Piezos will sound better to the ear. The multiple elements cause a natural flattening of response, while lowering the vertical dispersion angle which under most circumstances is a good thing. Less EQ is required, less amps and power is required, and far less money is spent.

BFM sound is all about if it sounds good go with it, whether its got perfect polars or waterfalls or not isn't the main goal over there. Its that the cabs create an efficiency increase (sometimes extremely) over a reflex cab (that most people were previously using). Because they are all horn loaded IMO you get increased fidelity from the lower distortion figure, and the fact that they are so cheap to build is a bonus. Thats what its all about. Beyond that you can get very serious and technical about things but the price jump (and size and weight jump) between a BFM cab and something that has more engineering gone into it is so great that the allure is to good to resist for most people.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Tony Insanity
Date Posted: 22 April 2008 at 11:25pm
Originally posted by Disco Stu Disco Stu wrote:

Originally posted by Tony Insanity Tony Insanity wrote:

Why piezo's? Smile


Why not?

Before you ask, there have been pretty exhaustive tests made by myself and others on the BFM forum on Piezos. I personally listened to the different models to see which ones sound best on their own and in groups.

Others have tried Piezos vs compression drivers, and the result was that unless you pick a compression driver over at least £130, and couple it to an ideal horn, and then throw shedloads of EQ at it, a bank of Piezos will sound better to the ear. The multiple elements cause a natural flattening of response, while lowering the vertical dispersion angle which under most circumstances is a good thing. Less EQ is required, less amps and power is required, and far less money is spent.

BFM sound is all about if it sounds good go with it, whether its got perfect polars or waterfalls or not isn't the main goal over there. Its that the cabs create an efficiency increase (sometimes extremely) over a reflex cab (that most people were previously using). Because they are all horn loaded IMO you get increased fidelity from the lower distortion figure, and the fact that they are so cheap to build is a bonus. Thats what its all about. Beyond that you can get very serious and technical about things but the price jump (and size and weight jump) between a BFM cab and something that has more engineering gone into it is so great that the allure is to good to resist for most people.

Stu
 
Thanks for that comprehensive answer Stu.........must have a look at the BFM forum and read a bit more on this piezo thing. Smile


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.....you might also look for her companion, a large Chinese rabbit, who is easy to spot since he is only standing on his hind feet in the shade of a cinnamon tree...


Posted By: Disco Stu
Date Posted: 23 April 2008 at 12:01am
If nothing else there are two things worth reading about there

Piezos, and V coupling subs.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Steak'n'ale
Date Posted: 25 April 2008 at 12:48pm
You got any pics of what they look like without the grills? Looks like a nice little cab and easy to build too!


Posted By: Disco Stu
Date Posted: 25 April 2008 at 2:16pm
Not personally but I collected shedloads of BFM pictures from the past 8 years and uploaded them to photobucket so I am sure there will be some here.

http://s269.photobucket.com/albums/jj51/Billfitzmaurice/ - Bill Fitzmaurice Photo Album

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Disco Stu
Date Posted: 25 April 2008 at 2:22pm
Heres just a few



-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: ychole audio
Date Posted: 26 April 2008 at 10:26pm

Im using 6 omnitop15 as mid section of my rig,they were loaded with JBL E130's.The sensitivity and response is amazing.I know the omnitop12 should have been much better but i have already those speakers lying around.



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I am ZERIEL'S dad!!!


Posted By: Steak'n'ale
Date Posted: 08 May 2008 at 3:49pm
I'm really interested in building a set of these. I just have a few questions that I couldn't find answers for on the BF forum:
1) Whats this auto EQ thingy you say you use to make them sound good and how much does it cost?
2)When you say you cut down the piezos what do you mean? Do you just cut the sides off so the two horns meet without a flat bit in the vertical direction?
3) Have you heard these with the recommended drivers before as well as the P-audio one? Any comments on if you can get away without EQ if you use the 'proper' bits?


Posted By: Steak'n'ale
Date Posted: 08 May 2008 at 4:28pm
I've just been looking at the Celestion TN1225. This has similar parameters to the eminence and a slight upwards slope (and is mega cheap!).

Reckon it'd work well?


Posted By: Disco Stu
Date Posted: 08 May 2008 at 4:33pm
1) Auto EQ, a feature built into speaker management systems that acts as an analyser device in conjunction with a measurement microphone to enable relatively flat frequency response. The device does this by playing back pink noise through the speakers, analysing what gets picked up by the microphone and then EQing to make a flat response, or more or less, bearing in mind its only 31 band. You need something like a Behringer DEQ2496 and a Behringer ECM8000 measurement microphone to do this. OTOH if you have a 31 band graphic and use the exact same components as is recommended you can just go on the BFM forum and look for someone elses graphic EQ setup and copy that as a starting point, tweaking to taste.

2) Its all in the plans my friend. If you look at the pictures on the previous page of this thread you will see how people have cut down and glued piezos up together. The new melded array is in the latest version of the plans and has good output down to below 2kHz, it is the most advanced way to set up piezos but it takes the most work. Well recommended though.

3) No, I built these cabs with the following in mind. My previous attempts at getting a satisfying reflex box were never up to the standard I knew was possible. I had ordered 4 P.Audio SN12MB drivers from PAP with a view to putting them into reflex cabs. Then I went and heard the VOID Static 3, and was completely blown away with the quality of sound and the output. I could not build any more reflex boxes. I had to build horns. So 2 years down the line after buying the drivers, I decided I really ought to get them in boxes and out on the road. So I employed insomnia to build me some boxes with the condition that I would try the P.Audios first and see if they worked then if I wasnt happy, attempt to sell them and buy Deltalites. Soundsystem Dan I think on here has also built Omnitops and DRs and he used wharfdale drivers which worked fine apparently. So I figured there might be a bit more EQ required but it would be ok. As it turns out the P.Audios work better than expected so there is no need to mess about and change them.

As to your final question, no, AFAIK ALL speaker systems designed today, are designed to either use the custom processors that come with them or require EQ to make them sound good. There is no way around it, EQ IS necessary, but it doesnt have to be expensive. The omnitops require far less EQ than the DRs but still require it.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Disco Stu
Date Posted: 08 May 2008 at 4:39pm
Originally posted by Steak'n'ale Steak'n'ale wrote:

I've just been looking at the Celestion TN1225. This has similar parameters to the eminence and a slight upwards slope (and is mega cheap!).Reckon it'd work well?


The response plot looks very similar to the SN12MB

The Fs is quite high, but the rest of the specs look similar to the P.Audio and may well work.

Only way is to try, I would make sure you use the melded Piezo array to ensure that you get as much output in the 1-2Khz area as possible.

I had mine built just before the melded array was "invented" so I missed out, still looking at a retrofit though.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Disco Stu
Date Posted: 08 May 2008 at 4:41pm
Look out for the depth of the driver though, the P.Audio JUST fits, the Deltalite is I think a bit shallower. That celestion looks quite deep, check it against the Deltalite and P.Audio to be sure.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Steak'n'ale
Date Posted: 08 May 2008 at 4:42pm
Sounds good. I might try to build a set using the celestion driver then and just budget for the EQ stuff like you say.

Time to give BMF some money...


Posted By: soundsystemdan
Date Posted: 08 May 2008 at 5:22pm
Originally posted by Disco Stu Disco Stu wrote:

Soundsystem Dan I think on here has also built Omnitops and DRs and he used wharfdale drivers which worked fine apparently.


I have built Omnitops, but no DR's.
The Wharfedale drivers were fine, but as i wanted them back in their original cabs I eventually got the money together for some Deltalites. This brought an improvement, mainly in the form of an extra dB or so.



-------------
http://dancomsound.com" rel="nofollow - http://dancomsound.com


Posted By: Disco Stu
Date Posted: 08 May 2008 at 6:16pm
Before you do.... what are you planning to use em for?

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Steak'n'ale
Date Posted: 09 May 2008 at 2:51am
Playing music loud Big%20smile for sheets and giggles and because building speakers is fun.

I'd quite like to build some brown note horns Wink at some point so might need some top first as my mate already has more bass than he knows what to do with. I might need some help on the low crass filters for the brown note horns too.


Posted By: odc04r
Date Posted: 09 May 2008 at 3:32am
Your first cab should be one that can be taken to many house parties. Important design consideration.

(and because my old double 15s use eminence delta drivers there's not much low end to annoy the neighbours!)


Posted By: Disco Stu
Date Posted: 09 May 2008 at 10:15am
Originally posted by Steak'n'ale Steak'n'ale wrote:

Playing music loud Big%20smile for sheets and giggles and because building speakers is fun.I'd quite like to build some brown note horns Wink at some point so might need some top first as my mate already has more bass than he knows what to do with. I might need some help on the low crass filters for the brown note horns too.


Brown note is a myth, was tested out a couple of years back with some serious SPL bass cabs, but nothing, nada, no brown trousers in sight.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Steak'n'ale
Date Posted: 09 May 2008 at 12:34pm
Yeah, I know. They did it on myth busters and didn't find anything.

Its still funny though. Anyone modelled a bumhole as a ring occillator?


Posted By: SteveAATW
Date Posted: 10 May 2008 at 12:01am
Stu how much did they come to per cab if you don't mind me asking? Need some decent SPL but small footprint midtops soon, look like these might be a good option - feel free to pm if you dont want to broadcast it


Posted By: toastyghost
Date Posted: 10 May 2008 at 2:09am
Originally posted by soundsystemdan soundsystemdan wrote:


Originally posted by Disco Stu Disco Stu wrote:

Soundsystem Dan I think on here has also built Omnitops and DRs and he used wharfdale drivers which worked fine apparently.
I have built Omnitops, but no DR's.The Wharfedale drivers were fine, but as i wanted them back in their original cabs I eventually got the money together for some Deltalites. This brought an improvement, mainly in the form of an extra dB or so.


timebomb on here is the man to ask about DRs, he's built 250s and 300s I believe.


Posted By: DJ Nick
Date Posted: 10 May 2008 at 2:38am
Nice Cabinets INSOMNIA Big%20smile
 
They look very nicely built! must have taken some time...
 I Think that this is a very interesting design, and must be bloodu LOUD too... i wonder what the sensitivity is on these, any ideas?
Also i would be interested in listening to these one day
well done you should be proud,,,building horn loaded mids is a time consuming task.


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It's the thought that counts


Posted By: soundsystemdan
Date Posted: 10 May 2008 at 8:48am
The greatest virtue of these cabs is they're NOT that difficult to build, although I had to do a bit of bodging with the horn top and bottom, it was nothing a bit of filing and filling wouldn't fix.
Sensivity iirc is ~103-104dB/m


-------------
http://dancomsound.com" rel="nofollow - http://dancomsound.com


Posted By: norty303
Date Posted: 10 May 2008 at 1:35pm
Quote Brown note is a myth, was tested out a couple of years back with some serious SPL bass cabs, but nothing, nada, no brown trousers in sight.
 
Thats because they didn't do it right.  Just because they're Myth Busters, doesn't mean they know what they're doing all the time.
 
Serious SPL on its own won't do it, you need to be hitting the resonant frequecy of the bowel, and that is in the 7-10hz range, something that they were a looooong way from in the tests.  Although they had a nice lot of Meyer cabs there, none of those were suited to producing such a low frequency with any sort of efficiency.
 
The best way to learn about 'brown note' type effects is to read up on acoustic weapons tests, where they 'do' have evidence to suggest you can create nasty physical and psychological effects through noise/sound.  There is one website out there that gives the details of how to turn a room into a fairly effective VLF helmholtz resonator using power as small as 30w.
 
Not the article i was referring to but some interesting items...
 
http://findarticles.com/p/articles/mi_qa4075/is_200410/ai_n9469296/pg_5 - http://findarticles.com/p/articles/mi_qa4075/is_200410/ai_n9469296/pg_5


-------------
My laser stuff: http://www.facebook.com/SubsonicSystems" rel="nofollow - Frikkin Lasers


Posted By: Steak'n'ale
Date Posted: 10 May 2008 at 10:54pm
7Hz was where I thought it was meant to be. I never really looked at how they did it, just heard they didn't find it.

Everything has a resonant frequency...


Posted By: Timebomb
Date Posted: 11 May 2008 at 12:26am
I remember watching that episode of mythbusters and thinking that an engineer sent from meyer should be a bit more objective in his experements, his test blantntly didnt proove anything but reconed he did.  I seem to remember they had the same guy on to prove a ducks quack does eco, took him about 5 trys, seemed like a qwack has no clear impusces do dificult to distinguish between the source and the reverberation. 

How do the omnitops sound in the low mids stu?  Im interested how tight the kick range is on these with it being a ported short horn with no real frount chamber rarther than a long horn, the DRs sound really nice in the kick range but you have to run them down to about 90Hz to get that nice kicky effect from them, unfortunatly this eats up headroom with most dance music so i cross them higher a lot of the time.  

-------------
James Secker          facebook.com/soundgearuk
James@soundgear.co.uk               www.soundgear.co.uk


Posted By: Disco Stu
Date Posted: 11 May 2008 at 12:48pm
Originally posted by norty303 norty303 wrote:

, you need to be hitting the resonant frequecy of the bowel, and that is in the 7-10hz range, something that they were a looooong way from in the tests.  Although they had a nice lot of Meyer cabs there, none of those were suited to producing such a low frequency with any sort of efficiency.
 


This is true, just use a church organ pipe, easiest way.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Disco Stu
Date Posted: 11 May 2008 at 12:55pm
Originally posted by Timebomb Timebomb wrote:


How do the omnitops sound in the low mids stu?  Im interested how
tight the kick range is on these with it being a ported short horn with
no real frount chamber rarther than a long horn, the DRs sound really
nice in the kick range but you have to run them down to about 90Hz to
get that nice kicky effect from them, unfortunatly this eats up
headroom with most dance music so i cross them higher a lot of the
time.  


Well I would expect the DRs to be better in this regard, the horn loading provides support to much lower down in the frequency range, the OT12 starts to lose its horn support below 200Hz, thats not to say its not still good in that range, but I dont think it would have as much clout as a DR300 down there.

The reason I went for the OTs over the DRs is simply because proportionally the box is a lot more scaleable to the application. I dont always do gigs that would require a DR250/280 so I stuck it with the OTs. Much smaller boxes and a not unreasonable 104dB on paper down to 200Hz and 12dB rolloff below that, pretty reasonable for the box size.

Its a ported horn but the port is really providing support at 60Hz, to help control excursion and keep the reflex portion of the box in operation to as low a frequency as possible. Its essentially the same as a 4560.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Steak'n'ale
Date Posted: 11 May 2008 at 11:04pm
Righto. I've bought the plans. Just been trying to find some decent 12mm ply to no avail. Any ideas? I'm sure suppliers must be on here somewhere but I can't find any.

I'm just surprised the plans came in inches! When it comes to doing a metric/imperial conversion what  tolerance should I use? nearest mm? 0.1mm? I'm slightly unsure how accurate my cuttings going to be.


Posted By: Disco Stu
Date Posted: 12 May 2008 at 12:42am
1/2" = 12mm

So long as all the bits fit together snugly thats all that matters, just stick to inches, draw the parts out and use lots of polyurethane adhesive.

Where are you based?

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Steak'n'ale
Date Posted: 12 May 2008 at 10:26am
Sheffield/Manchester. Whats this PU adhesive? When I used to build with Davey T we used PVA and it worked ok.


Posted By: toastyghost
Date Posted: 12 May 2008 at 12:48pm
Steak'n'ale: PM soundsystemdan, he's halfways between Sheffield and Manc and has made Omnitops, so should be able to give you a few tips.


Posted By: Disco Stu
Date Posted: 12 May 2008 at 6:46pm
Originally posted by Steak'n'ale Steak'n'ale wrote:

Sheffield/Manchester. Whats this PU adhesive? When I used to build with Davey T we used PVA and it worked ok.


I used PVA and it worked fine, if you know you can build to tight tolerance thats fine, its only because a lot of woodworkers are noobs Bill recommends the PU adhesive which expands to fill any gaps and saves you lots of potential problems if you have an air leak in your joint that you dont put enough PVA in to fill.

Stu




-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: Tony Insanity
Date Posted: 01 June 2008 at 9:22pm

I've just got some plans for the Omnitop 12 and initialy intend to build 4, if I like 'em I'll build another 4. 

Stu, you say you used the 'double element' type piezo, these: http://cpc.farnell.com/LS02368/audio-video-tv/product.us0?sku=unbranded-mpt-177 - http://cpc.farnell.com/LS02368/audio-video-tv/product.us0?sku=unbranded-mpt-177
 
how did you wire them? did you use a resistor?
 
The spl on these is 99db, is that the efficiency of  the ones you used?
 
I see some people have used these:
http://cpc.farnell.com/LS02367/audio-video-tv/product.us0?sku=unbranded-mpt-016 - http://cpc.farnell.com/LS02367/audio-video-tv/product.us0?sku=unbranded-mpt-016
 
they are only 91db, not sure these would be as good?
 
I need to order the peizos and was going to get the doubles but do the singles have any advantages? 


-------------
.....you might also look for her companion, a large Chinese rabbit, who is easy to spot since he is only standing on his hind feet in the shade of a cinnamon tree...


Posted By: Disco Stu
Date Posted: 01 June 2008 at 9:42pm
When I built mine melded array was not an option, but now it is THE only option in a lot of the plans so I would go with that.

Piezo sensitivity means nothing, bear in mind that the double element is just that 2x elements so its going to be 6dB louder anyway, also its not really about that you are using 12 1016 piezos in a melded array, 3x 1177 elements in series (which is 3 bank series parallel if you are using single tweeters) is enough to keep up with the woofer and give equivalent to 900W power handling. The benefit of the melded array is wider dispersion and lower frequency response which just helps to smooth the crossover point.

Stu

-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: djscooby
Date Posted: 03 January 2010 at 11:44pm
Does anybody have the plans for the omnitop12s and omnitop15s please fancy havin them built for me

-------------
Well my wife has kicked me out saying it's over due to my obsession with speakers don't know watt I'm gonna do with no ohm to go to


Posted By: Strange Daze
Date Posted: 04 January 2010 at 4:41pm

Originally posted by djscooby djscooby wrote:

Does anybody have the plans for the omnitop12s and omnitop15s please fancy havin them built for me


The donation is only a couple of quid on the site mate......support the designer and all that :)




Toasty.....Dan's OmniTops are awesome. Such a SUPER light cabinet, even when loaded.

I love them to pieces. By far the nicest sounding sub <£200 box you can make in my opinion.



Posted By: Disco Stu
Date Posted: 28 January 2010 at 11:59am
My Omnitop 12s as depicted on the first page of this thread are now up for sale.

Looking for £550 for all 4, simply to help cover the cost of having a pair of OT15s built (priorities change so my PA needs to).

PM if interested, a member of BFM site already has first refusal.

Stu



-------------
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches


Posted By: trentp
Date Posted: 17 January 2013 at 6:14pm
Hi Stu, can these perform well above some ES18'S and Hogs? I need to build some simple but adequate tops.


Posted By: Dub Specialist
Date Posted: 18 January 2013 at 1:22pm
Can someone correct me if im wrong is this the Original Omnitops 12s ?? Yes or No the reason why im asking i seen loads of differenet pics online/forums ect that are single 12s, a row of piezos running vertical twin 12s ect ect but there called Omnitops 12,

what drivers are recommend for this cab too? , or orther alternatives drivers

so are some of these modded cabs?

thanks 








-------------
treat all creation with respect. For music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion! MUSIC IS LIFE


Posted By: all bass
Date Posted: 18 January 2013 at 3:47pm
The shape of the omnitop 212 is just a variation on a very basic 2x12 horn that has been used for a long time. The thing that is really something unique is the melded tweeter array.


Posted By: Vert
Date Posted: 19 January 2013 at 9:39am
shot of the melded tweeter array on my DRs 

-------------
Box builder, pm for quote


Posted By: fordlltwm
Date Posted: 20 January 2013 at 2:15am
I'm considering buying the plans for the omnitops, but I'm wondering whether anyone knows of a cheaper driver that will work instead of the rather expensive deltalites?

Cheers


-------------
ELV-500
Marshall 6040
Inkel MX-1402

And a worrying amount of 100v line horns


Posted By: michalb
Date Posted: 20 January 2013 at 4:26pm
Hi I build my omni tops with the Beta 12 driver. They might not have the output of the more expensive drivers but 2 a side will hit 127db with 200w rms per driver.

http://www.eminence.com/pdf/Beta_12A.pdf

hope this helps


Michal


Posted By: Audio_AL
Date Posted: 20 January 2013 at 4:50pm
The least expensive recommended driver is the Eminence Beta 12. A high
performance alternative is the Delta Pro 12. For lighter weight, albeit at a cost, use
a neo magnet driver, such as the Eminence Basslite 2012, Deltalite II 2512 and
Kappalite 3012HO.


-------------
Make it loud!


Posted By: fordlltwm
Date Posted: 20 January 2013 at 5:20pm
Cheers, that looks rather more affordable, may go and shoot some $$'s at his site.


-------------
ELV-500
Marshall 6040
Inkel MX-1402

And a worrying amount of 100v line horns


Posted By: DiscoFish
Date Posted: 20 January 2013 at 5:35pm
Very nice work, love this style of cab. Bet they sound lovely Thumbs Up

-------------
Sam Owen
S.P.O Sound & Lighting


Posted By: fordlltwm
Date Posted: 20 January 2013 at 8:56pm
And in even better news, a friend of mine who works as a carpenter is willing to knock em from off cuts for a couple of pints :D


-------------
ELV-500
Marshall 6040
Inkel MX-1402

And a worrying amount of 100v line horns


Posted By: nuclearbass
Date Posted: 20 January 2013 at 10:46pm
My omnitops, they have some kind if phase bung infront if the driver which you cnt really see from this pic



-------------
one life - have fun!
Force fusion pro audio


Posted By: nuclearbass
Date Posted: 20 January 2013 at 10:48pm
Better pic



-------------
one life - have fun!
Force fusion pro audio


Posted By: bitSmasher
Date Posted: 21 January 2013 at 12:08am
edit: asked in your own system thread here: http://forum.speakerplans.com/nfusion-system_topic57389.html


Posted By: bitSmasher
Date Posted: 21 January 2013 at 12:10am
Originally posted by Dub Specialist Dub Specialist wrote:

Can someone correct me if im wrong is this the Original Omnitops 12s ?? Yes or No the reason why im asking i seen loads of differenet pics online/forums ect that are single 12s, a row of piezos running vertical twin 12s ect ect but there called Omnitops 12,

what drivers are recommend for this cab too? , or orther alternatives drivers

so are some of these modded cabs?

thanks 



Funnily enough that pic was posted by TonyASS in another OT12 thread: http://forum.speakerplans.com/omnitop-12-build-pics_topic10979_post102967.html#102967" rel="nofollow - http://forum.speakerplans.com/omnitop-12-build-pics_topic10979_post102967.html#102967
Where he states it's an old design by him...


Posted By: tv00
Date Posted: 16 November 2015 at 8:46pm
How do these monsters sound?

I'm quite skeptical, but that's mainly from reading billfitz writing silly things on forums where I can't comment. Some people just get religious about speakers, so it is with billfitz, suddenly people actually believe that he is the greatest speakerdesigner in the world and only he can figure it out!
Truth is there's many good designers and no one will ever figure it out:-)

Any competent comment would be appreciated!
+measurements, I saw one on a forum, looked pretty bad, -could be other factors like the room.


-------------
www.facebook.com/babysoundsystem



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