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Old 20th January 2009, 01:54 PM   #1
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Default 3 way full horn design v2

While in Japan, I design a 3 way full horn speaker based on the excellent work of Bruce Edgar for the calculation of the expansion but with only one 90 degree bending.

The difficulty is that it is impossible to achieve good matching with driver (JBL 2451) if the mass roll off frequency is not around 600 hz. This is the main reason why I used the JBL E120 that gives me a flat response up to around that frequency.

I have enjoyed the system for the past 8 years but I am now looking for a driver with a lower FC (presently there is no response below 60 hz) so that I can design an horn that could go lower (ideally 45 hz) but still retain the higher roll off.

The ideal TS parameters would be the following:

FC : 35 to 45 hz
VAS : around 70
Qe : lower than 0.12

Anyone has a candidate for that? I will also post pictures of the present speaker

Thanks for your help

Noe from Singapore
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Old 20th January 2009, 03:09 PM   #2
pk is offline pk  Denmark
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Hi Noe,

I think it will be fairly difficult to find a driver meeting these specs. Only very few "of the shelf" drivers have such a low Qe.

I only know of two drivers that come close to the specs you are looking for:

10" Beyma 102Nd

12" Beyma 122Nd

Good luck!

Best regards
Peter
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Old 20th January 2009, 09:36 PM   #3
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Qes of .12 is extremely low and will take a massive motor. It can be done, but would be pricey. As far as off the shelf goes the TD10M is close in Fs and Vas although Qes is higher. At Qes of .26 though it still has quit a big of motor strength. http://aespeakers.com/shop/catalog/p...products_id=64

Depending on what you need for Xmax, a shorter flat wire copper coil could get Qes down close to that range. A larger diameter coil could accomplish it quite easily.

John
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Old 21st January 2009, 12:21 PM   #4
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Dear Peter and John,

Thanks for your help there but the most important for me is to have a driver with a Qes around 0.12, for horn loading, it is by far the most important factor if we want to have control over the horn and make the response as flat as possible.

I have tried to find a driver like that for quite some time but it seems like it is impossible to find one with a low FC.

I was browsing the internet today.. I had some free time during lunch ! and found something interesting in the website of Fertin and Supravox.

Interestingly, they both use field coil magnets and this seems to play the trip. I have called Fertin and send an email but no reply !

Anyone has ever used a field coil speaker in a front loaded speaker before?

Here is a picture of my current 3 way horn speakers ! Now is time for the V2 of those.

Cheers
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Old 21st January 2009, 03:49 PM   #5
tinitus is offline tinitus  Europe
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Quote:
Originally posted by noesaglio
Dear Peter and John,

and found something interesting in the website of Fertin and Supravox.

Cheers

I did think about those too, so I will rspond to that
if they would do then a EMS might too

http://www.emspeaker.fr/home_ger.html

Precision Devices (UK) have one or two heavy duty woofers with similar specs

GreatPlainsAudio ought to have good woofers fore horns

And GOTO, if you have that kind of money

But its not clear to me which size woofer you need
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Old 22nd January 2009, 04:42 PM   #6
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hi Tinitus,

I had heard of Great Plains and they have some fantastic speakers but like Goto the price is also stratospheric

EMS looks like a very good lead and it is also easier to find 12 inch speakers that have a lower Qes and a not too low FS. I will definitely post an email to them to see what they can propose.

I have run some simulations with 15 inch units and it is always hard to get them to sing above 300 hz. The matting with a driver becomes then difficult.

Thanks for the lead ! I will keep you posted of the result of the enquiry.

Attached is another picture of the speaker
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Old 22nd January 2009, 05:31 PM   #7
SunRa is offline SunRa  Romania
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I don't see any picture...
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Old 22nd January 2009, 06:09 PM   #8
tinitus is offline tinitus  Europe
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Quote:
Originally posted by noesaglio
hi Tinitus,

I had heard of Great Plains and they have some fantastic speakers but like Goto the price is also stratospheric

EMS looks like a very good lead and it is also easier to find 12 inch speakers that have a lower Qes and a not too low FS. I will definitely post an email to them to see what they can propose.


Hi

I agree, Goto is rediciously expencive

GreatPlains I reckon is not that far from EMS
I got a price of 750EUR from EMS fore a pair

You could also look at AESpeakers(USA), pretty nice too
All sizes in the H-series Lambda have very low Qts

I reckon its not relevant when wanting good mids, but some of the Peerless XLS an XXLS sub driver have very low Qts
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Old 22nd January 2009, 06:13 PM   #9
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http://www.eighteensound.com/index.a...roduct&pid=239

Qes 0,15
Qts 0,14
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Old 22nd January 2009, 06:20 PM   #10
tinitus is offline tinitus  Europe
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