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Bill Fitzmaurice - Omnitop 12s (built by Insomnia)

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Tony Insanity View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tony Insanity Quote  Post ReplyReply Direct Link To This Post 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
.....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...
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Disco Stu View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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
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Steak'n'ale View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steak'n'ale Quote  Post ReplyReply Direct Link To This Post 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!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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.

Bill Fitzmaurice Photo Album

Edited by Disco Stu - 25 April 2008 at 2:16pm
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output

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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: 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
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ychole audio View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ychole audio Quote  Post ReplyReply Direct Link To This Post 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.

I am ZERIEL'S dad!!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steak'n'ale Quote  Post ReplyReply Direct Link To This Post 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?
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Steak'n'ale View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steak'n'ale Quote  Post ReplyReply Direct Link To This Post 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?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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
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Disco Stu View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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
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Disco Stu View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Disco Stu Quote  Post ReplyReply Direct Link To This Post 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
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Steak'n'ale View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steak'n'ale Quote  Post ReplyReply Direct Link To This Post 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...
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