Why Scanspeak rising frequency response in woofers??

Daveis · 26th October 2008, 06:53 PM

Scanspeak designs a rising frequency response into their woofers above 1kz.

How does one handle this in the crossover?

Why is it meant to make the crossover simpler?

I guess Scanspeak is ASSUMING you will use a particular crossover, but I don't know what that is..

Help.

tinitus · 26th October 2008, 07:03 PM

I use a 5" SS Revelator midwoofer in a 3way, and it needs a "notch" filter

In a 2way many will "attack" the driver early with a big inductor to deal with BSC, and at the same time deal with the rise and probably what you refer to as "simple" xo

454Casull · 26th October 2008, 07:51 PM

If you're reading their graphs I think it's because they don't include BSC and they test in a smallish sealed enclosure.

Daveis · 26th October 2008, 08:36 PM

I've seen comments like this. Trying to understand maybe with an example crossover what this means.

Are there any reference designs for 8831G, 8530K, etc. from Scanspeak that show how they expect the driver to get used?

http://www.htguide.com/forum/showthread.php4?t=10944

Also, classic SS drivers have that tiltup above 800 Hz so that you can use a single pole in the crossover around 250 and not have to play as fancy an impedance control tricks to put a zero in the response to stop the BSC - hence the 800 Hz rise. It can simplify the crossover. BUT, one side effect is that the cone's first mode is at 800 Hz, creating a coloration. I used to use these SS drivers in the early 90's, but haven't for a long time- I find I prefer pistonic performance to beyond the crossover region- midrange is clearer.

Look at
http://www.tymphany.com/files/produc...5W_8531K00.pdf
http://www.tymphany.com/files/produc...5W_4531G00.pdf

Why the heck would you want the on-axis woofer response to go up 4-6db's, have the off-axis response drop like a rock from 2khz on, but have the on-axis response shelved high out to 5khz?

And then the Illuminator,

http://www.tymphany.com/files/produc...WU_8741T00.pdf

What is happening at 5khz on that driver?

454Casull · 26th October 2008, 08:42 PM

Sorry, I misread 1kHz. Can't help you there.

Mario Pankov · 3rd December 2011, 06:54 PM

Thread is 3 years old, but I have pm you.

26th October 2008, 06:53 PM	#1
Daveis diyAudio Member Join Date: Dec 2003 Location: Des Moines, IA	Why Scanspeak rising frequency response in woofers?? Scanspeak designs a rising frequency response into their woofers above 1kz. How does one handle this in the crossover? Why is it meant to make the crossover simpler? I guess Scanspeak is ASSUMING you will use a particular crossover, but I don't know what that is.. Help.

3rd December 2011, 06:54 PM	#6
Mario Pankov diyAudio Member Join Date: Aug 2007	Hi Thread is 3 years old, but I have pm you. __________________ www.mariopankov.com

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26th October 2008, 07:03 PM	#2
tinitus diyAudio Moderator Join Date: Nov 2005	I use a 5" SS Revelator midwoofer in a 3way, and it needs a "notch" filter In a 2way many will "attack" the driver early with a big inductor to deal with BSC, and at the same time deal with the rise and probably what you refer to as "simple" xo

26th October 2008, 07:51 PM	#3
454Casull diyAudio Member Join Date: Jan 2004 Location: Toronto, ON, Canada	If you're reading their graphs I think it's because they don't include BSC and they test in a smallish sealed enclosure.

26th October 2008, 08:36 PM	#4
Daveis diyAudio Member Join Date: Dec 2003 Location: Des Moines, IA	I've seen comments like this. Trying to understand maybe with an example crossover what this means. Are there any reference designs for 8831G, 8530K, etc. from Scanspeak that show how they expect the driver to get used? http://www.htguide.com/forum/showthread.php4?t=10944 Also, classic SS drivers have that tiltup above 800 Hz so that you can use a single pole in the crossover around 250 and not have to play as fancy an impedance control tricks to put a zero in the response to stop the BSC - hence the 800 Hz rise. It can simplify the crossover. BUT, one side effect is that the cone's first mode is at 800 Hz, creating a coloration. I used to use these SS drivers in the early 90's, but haven't for a long time- I find I prefer pistonic performance to beyond the crossover region- midrange is clearer. Look at http://www.tymphany.com/files/produc...5W_8531K00.pdf http://www.tymphany.com/files/produc...5W_4531G00.pdf Why the heck would you want the on-axis woofer response to go up 4-6db's, have the off-axis response drop like a rock from 2khz on, but have the on-axis response shelved high out to 5khz? And then the Illuminator, http://www.tymphany.com/files/produc...WU_8741T00.pdf What is happening at 5khz on that driver?

26th October 2008, 08:42 PM	#5
454Casull diyAudio Member Join Date: Jan 2004 Location: Toronto, ON, Canada	Sorry, I misread 1kHz. Can't help you there.

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