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Bill Fitzmaurice - Omnitop 12s (built by Insomnia)

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Disco Stu View Drop Down
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    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


Edited by Disco Stu - 10 April 2008 at 11:48pm
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

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Post Options Post Options   Thanks (0) Thanks(0)   Quote mylesound Quote  Post ReplyReply Direct Link To This Post 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

Edited by mylesound - 11 April 2008 at 3:55am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jake_Fielder Quote  Post ReplyReply Direct Link To This Post 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.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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

Edited by Disco Stu - 11 April 2008 at 12:59pm
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Strange Daze Quote  Post ReplyReply Direct Link To This Post Posted: 11 April 2008 at 1:31pm
they look great :)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jake_Fielder Quote  Post ReplyReply Direct Link To This Post 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?
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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


Edited by Disco Stu - 11 April 2008 at 5:34pm
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

My acts:
www.myspace.com/thebowiexperience
www.myspace.com/scheisseelektronisches
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tony Wilkes Quote  Post ReplyReply Direct Link To This Post 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
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mylesound Quote  Post ReplyReply Direct Link To This Post 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?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark James Quote  Post ReplyReply Direct Link To This Post 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.........
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?
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