Home » Sponsored » Pi Speakers » P.Audio SD-450 N on JBL 2370 Bi-Radial Horn with Wayne Parhams compensation circuit
Re: Radial horns [message #40393 is a reply to message #40381] Sun, 23 February 2003 16:24 Go to previous messageGo to next message
bmar is currently offline  bmar
Messages: 346
Registered: May 2009
Grand Master
Hi Alex,

I think it's great your going to make some wood horns. There are a few devices you can use for connecting a driver to the wodd flare that you built. Fane makes some adaptors and Selenium makes adaptors also. These could be used in some fashion for a fit up of the compression driver to the horn flare. There are also some older JBL adaptors that are 1" to 2". I find the JBL models a little long and for that matter, adaptors and mounting flanges by any of these companies have not been to my liking. So, I have my own design and specifications made. They are available, and you can see pricing and detials on the pricing page of the www.woodhorn.com web page.

You may also find it rather difficult to get a compression driver to perform well in the lower range your looking for. Although some models will spec out to 300 or 400 hz. Its also possible to build a horn that will give you that cut off. What you may find is that even though a combination of horn and driver will spec out or test to give you suitible results. The sound you hear may not be desirable.

I have had fantastic results using 2" drivers on larger horns with a crossover point of 700hz (give or take 50hz). This is a very dynamic combination. I like to use 1500-2000hz crossover point for 1" compression drivers.

You could built a larger horn that is about 400 x 400mm. use an 8" cone driver and have a great range of use from 200hz - 2000hz.

Bill

two cents from a 2370 user [message #40395 is a reply to message #40378] Sun, 23 February 2003 21:23 Go to previous messageGo to next message
ToFo is currently offline  ToFo
Messages: 219
Registered: May 2009
Master
Adrian,
if you decide to go with JBL I can say the sound is superb for hi-fi or pro use. Since you make dispersion a priority I think you would like it as the dispersion is incredible(diffraction slot). I built my Pi speakers using 2370's and I love em. You can certainly find more attractive horns, but they look better than other plastic horns they even look better than a lot of metal horns. For the price you mentioned they are a steal. You will not find a better horn(your subjective mileage may vary).

*note in my experience 2370's need less compensation than many other horns. A .33 or .22mF should work fine, but that depends on the compression driver. I remember thinking the P Audio had good top end when I considered it a while back. It should do great.

Have fun!
Thomas

Re: Radial horns [message #40396 is a reply to message #40393] Sun, 23 February 2003 23:33 Go to previous messageGo to next message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)

Hey Bill. Just figured out your the Martinelli Sound guy, lol, nice work on the horns! They look very nice, I bet they sound great also. I've just been looking at the price list and it seems what I need to attach the compression driver to the horn is a throat flange (is this all I need?). And by the looks of it the AT-1 and AT-2 models you have are both for 1" drivers, and the AT-3 is for 2". Out of the 1" models, which would you reccomend?

Are the prices in US dollars? Each flange for 1"ers is US$135... a bit high for me, I'm in australia so converted around AU$270 or something + postage. But I cant resist the look of the wood horns! So many decisions......

I've seen your main speakers on the site using the 15" 2226H, and the 8" horn loaded speaker (oh yea what brand/model are these?) and 1" compression driver. Awesome! But how did you horn load the 8", do you need throat flanges etc? From the pic, it looks like the whole cone is visible, I dont understand how the horn does anything for it!

Do you think a scanspeak 8" would work well horn loaded? They make some pretty powerful drivers I hear, plus I can get them locally.

BTW: The insturctions on making the horn on your site, I believe it goes to 800Hz or something, what dispersion pattern is this? (90x40 degrees?). I also noticed there were no measurements for the wood there! Makes it a bit difficult for me to build! Thought it might just be you dont want to give away your ideas, etc, thats ok i understand!

Re: Radial horns [message #40397 is a reply to message #40389] Sun, 23 February 2003 23:40 Go to previous messageGo to next message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)

Hey Wayne. Would you say then I should use a 1" driver crossed like 2Khz then, and use a horn loaded 8" that bmar (Bill/Martinelli Sound guy) suggested in the other post? Or do ya think it is not really necessary?

> better crossover below 200Hz

I'd assume not with the compression driver ?? !!!!!!!

Is there any sonic differences between plastic/ABS and metal horns?

Probably said this a million times, I'll say it again though lol you've been a big help so far and thanks for your time.

Adrian

Re: two cents from a 2370 user and compensation circuit!!!! [message #40398 is a reply to message #40395] Sun, 23 February 2003 23:51 Go to previous messageGo to next message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)
Hey Thomas, thanks for your input. I'm glad to see you've had success with the P.Audio stuff.

>*note in my experience 2370's need less compensation than many
> other horns. A .33 or .22mF should work fine, but that depends on
> the compression driver. I remember thinking the P Audio had good
> top end when I considered it a while back. It should do great.

Hmmm, I've just went back to Waynes compensation figures, it says use a 0.47uF bypass cap to remove attenuation on the top octave with a resistor picked from the chart below:


Ohms Decibels Power
===============================
0.0 0dB 100%
2.5 2.4dB 58%
5.0 4.2dB 38%
7.5 5.4dB 27%
10.0 7.0dB 20%
15.0 9.2dB 12%
25.0 12.3dB 5.9%
34.0 14.4dB 3.6%
37.5 15.1dB 3.1%
41.0 15.7dB 2.6%
50.0 17.2dB 1.9%

You've told me 33 or .22mF should be fine with this horn/driver combo, is this for the bypass cap? How do I convert mF to uF? Oh yea, what sort of caps should I use? (greencaps, MKT's, electrolics or however you spell it lol).

I just realized I dont know how to pick what resistor to use from the chart above lol. Although wayne said a 25 or 50ohm in most cases should work well. How can I determine from the above what is needed?

Thanks! Adrian

Re: P.Audio SD-450 N on JBL 2370 Bi-Radial Horn with Wayne Parhams compensation circuit [message #40399 is a reply to message #40387] Sun, 23 February 2003 23:53 Go to previous messageGo to next message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)
Thanks for the feedback! Am interested to know why you used 100 x 60 horns instead of 90 x 40? I suppose its not that much of a deal though!

Adrian

You've got mail! [message #40400 is a reply to message #40398] Mon, 24 February 2003 00:17 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)
Series resistance of 25 to 50 ohms works well for driver padding, in some cases. But this is for a series attenuator, and it really only works if the load is purely resistive. I suggest you use Spice to evaluate your particular configuration.

The attenuator value chart you posted works very well in many cases and it is simple. But it is perhaps an oversimplification, and you would probably be better served to work from one of my existing crossover designs than to use this simplified chart. So check your E-Mail address because I've sent you the schematic for the π crossover. This circuit will do exactly what you want and provide the response curve you need.

Re: Radial horns [message #40401 is a reply to message #40397] Mon, 24 February 2003 00:27 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)
You can run a midrange horn with an 8" to 12" cone driver from 100Hz or 200Hz up to the compression driver crossover point. That's an excellent system.

As for horn material, that will determine how it sounds when the mouth rings like a bell. If braced and damped properly, it doesn't matter much. But some metal horns ring when struck, and this can become audible when excited by music content.

Re: You've got mail! [message #40402 is a reply to message #40400] Mon, 24 February 2003 00:31 Go to previous messageGo to next message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)

Hey Wayne, I havn't recieved the email yet, is it a large file? Maybe its just taking a while, if you decide to send it again the address is macky888@wasp.net.au in case its mucked up anywhere but I dont think so :P :)

Thanks!

Adrian

Re: Got it! [message #40404 is a reply to message #40402] Mon, 24 February 2003 00:46 Go to previous messageGo to previous message
Adrian Mack is currently offline  Adrian Mack
Messages: 568
Registered: May 2009
Illuminati (1st Degree)
Thanks! I've recieved it now and am reading over it, I'll post back if I have any problems :)

Adrian

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