Which drivers for my next open baffles?

[SimontY]

Hi all,

I've built and been progressing steadily my first ever open baffle speakers, which are 3-way using a cheap 1" tweeter, 4" Audax aerogel mid and 4 x 7" cheap woofers. After much tweaking I now have great sound. I'm not very keen on the Audax mid though, which sounds thin whatever I do in the crossover.

Winding thread, which is me learning about the concept and building and tweaking them:
My dipole experiment

Content with OB as a concept I would now like to progress with more impressive drivers. I have in mind another 3-way, this time using a more wide-band mid driver and larger woofers. To begin with it will be all passive and use Graham Maynard's T-bass circuit for ~6dB gain at woofer resonance. My amps are good for 180w/4ohms. My "dream" is to build class A amps for the midrange/top and relegate my Marantz monoblocks to bass duties. In would come an active crossover and I would consider mild bass-only EQ.

For the mid I'm considering something like a Goodmans Audiom 201 (12"), which I've heard in a large box and was stunned by the dynamics and naturalness. Alternatively, and a very different beast, a CSS FR125 (modern 4.5" full ranger). With the latter I wouldn't need a tweeter. I am not against 1st or 2nd crossover slopes. I have a basic measurement mic setup now.

Due to room constraints the baffle width forces me to use 12" drivers. 2 x 8ohm PA woofers would do this I believe. That's not so hard to choose - I'll look for something with medium-high Qts and low Fs.

Would anyone like to share their views on the CSS or Goodmans vintage drivers? I'd love to hear from someone who's heard both or similar drivers in an OB speaker. I will be hearing the CSS this Sunday, so that may clinch it or otherwise.

Thanks,
Simon

[tinitus]

Originally posted by SimontY
Hi all,

I'm not very keen on the Audax mid though, which sounds thin whatever I do in the crossover.

Have you tried a "1.order"/RC with a notch ? and you may need more "padding", both mid and tweet - RC on tweeter as well

[Rudolf]

Originally posted by SimontY
Alternatively, and a very different beast, a CSS FR125 (modern 4.5" full ranger). With the latter I wouldn't need a tweeter.
Would anyone like to share their views on the CSS or Goodmans vintage drivers?

Simon,
in this country people rave about the Tangband W3 1320 (underhung voice coil and copper sleeve) and W5 1611 as the more "complete" FR drivers in the price range of the CSS. May be you want to look into them

Here is a look inside the W3 1320.

[SimontY]

Originally posted by tinitus
Have you tried a "1.order"/RC with a notch ? and you may need more "padding", both mid and tweet - RC on tweeter as well

I've tried a 1st order with RC/zobel. I've not tried a notch filter as there's nothing to notch. The problem might be with stored energy/resonance in the upper midrange (looks like it on a waterfall plot).

The best solution was to let the woofers overlap a lot, just running them 1st order with a huge inductor in series. This is really musical. I will probably try to sell those speakers as I don't need two sets.

Simon

[SimontY]

Originally posted by Rudolf

Simon,
in this country people rave about the Tangband W3 1320 (underhung voice coil and copper sleeve) and W5 1611 as the more "complete" FR drivers in the price range of the CSS. May be you want to look into them

Here is a look inside the W3 1320.

That driver looks wonderful Rudolf. It doesn't appear to be available in the UK though, which puts me off a lot. Do you think these smaller, modern drivers can compete with something large with a big magnet, such as a Goodmans Audiom 201, 301, 61 etc.?

Simon

[Rudolf]

Simon,

www.spectrumaudio.de is the most comprehensive source of FR drivers in Germany. They do business with the UK too. Just send them a mail.

I mentioned the Tangbands only in comparison to the CSS.

The bigger Goodmans drivers are another league. I never heard any Audiom, so can´t really comment. Of course they had been constructed with more OB in mind than most modern FR drivers. But perhaps you will need a tweeter for their top end.

[SimontY]

Thanks Rudolf,

That site's CHOCK-FULL of exciting drivers!

You seen this?

http://www.spectrumaudio.de/breit/ta...dW51611SA.html

Simon

[tinitus]

Theres an interesting 12", Senon with OB specs and lowish sensitivity, 27EUR
New is also MarkAudio

[SimontY]

Originally posted by tinitus
Theres an interesting 12", Senon with OB specs and lowish sensitivity, 27EUR
New is also MarkAudio

Well spotted sir!!! That has mega-Qts and is big and cheap!!! I might even buy some of those babies!

Hmm, just noticd 1.5mm XMAX. That might not sweep enough volume..

Thanks,
Simon

[Graham Maynard]

Hi Simon,

If you are purchasing anew I would second Rudolph's recommendation of an underhung voice coil for mid/high frequencies. There is so much more detailed reproduction when compared to overhung, but bass drive needs to be limited (much as you did before).

Cheers ......... Graham.