Dipole Woofer for upper bass Recommendation

Hara · 10th June 2007, 11:31 PM

Hello,

I am going over revisions for my final dipole speaker design and I am lacking good choices for a good woofer with the following criteria.

Low as possible distortion
Used Bandwidth: (80-100, preferably low) - 250hz not including bandwidth for crossover slopes

Linear output within used SPL
SPL range: up to 105 db
This tends to require drivers (using SL's dipole_spl excel sheets) with a bare minimum of 190 cm^2 surface area (or about 8" diameter) with 5mm of xmax. High xmax helps but consider the tradeoff of low distortion vs xmax. (http://www.zaphaudio.com/lowxmax.html)

Driver size should be less than 15", preferably less.

Sensitivity: Greater than 87db/watt*m

Preferably Qts between .5 and .7 for simplified filter design

Finally,
Price: $30-$80 per driver

Driver's Currently considered:
Peerless SLS 12" and 10" ~$60
Dayton RS270 10" ~$30

Any suggestions or data on such drivers would be greatly appreciated.

bigwill · 10th June 2007, 11:34 PM

I know it's 15" but consider the Eminence Beta 15

Qts of around 0.6 iirc, senstivity around 98dB

xmax of 4mm, but it's 15"

Fs of 35Hz so It should easily cover the range you want

Quite a linear response in the range you want too

Hara · 10th June 2007, 11:43 PM

Thank you for your response.

Do you have any data on its harmonic distortion or links to people who have tested them?

bigwill · 10th June 2007, 11:53 PM

Quote:

Originally posted by Hara
Thank you for your response.

Do you have any data on its harmonic distortion or links to people who have tested them?

Not offhand, but considering it's a high efficiency PA driver designed to be hammered with hundreds of watts, I think at home listening levels it would be quite low. This is just a guess though.

ScottG · 11th June 2007, 06:05 PM

If I were you I wouldn't get "hung up" on low non-linear distortion, though sometimes audible with test tones - I personally find even fairly high non-linear distortion to be in-audible for music (order vs. spl dependent).

I use two of these per side parallel connected (i.e. 8 ohms nominal):

http://www.shredmuzic.com/product_p/813-010.htm

I have no idea what the distortion spectrum/level is like with them.. however:

1. They sound good in this application,
2. They are limited in fs - allowing for lower nominal distortion when considering excursion,
3. 2 drivers are better than one (..again, lower nominal distortion),
4. They have more mass - which provides a bit more "punch" in this region (..though marginally at the expense of "delicacy" depending on the pairing amplifier),

Caution: The drivers have 3 inch VC's - this may allow for less distortion near fs (and they are also vented), but conversely more distortion at higher freq.s (>1 kHz).

Additionally, IF you purchase them - make sure to "test" the drivers with various music to make sure you don't get a driver with poor gluing at the surround that makes a buzzing sound (..one of my 4 drivers did this prior to modification to fix it - of course you can always return the driver for a new one).

Hara · 11th June 2007, 08:39 PM

I'm concerned for low harmonic distortion measurements simply because the other drivers used in my design are also quite low. Vifa XG18, and Seas H1212. So for the sake of matching well together I thought it would be a good idea to also have low distortion woofers. Also for comparison reasons, having more numbers helps.

They are relatively cheap drivers so going two per cabinet allows me to go even lower down to 50-60hz which is a nice benefit, but not a requirement.

I checked madison's website, they do not provide complete datasheets on their drivers. While I'll be adding filters, it would be nice to know what kind of filters they would need. (From the given parameters, I just ran it through winISD in a large box to see its response, and it does look good for this application.)

I will of course be testing the purchased drivers (whichever I choose) for final consideration.

Anyways, thank you for your suggestion ScottG, it looks like a good candidate and will be considered.

I have basically till the end of next week to decide, just so I can start working on it.

Also, is there any woofer testing site that compare many woofers around this range? I know there are a few for the subwoofer range, midrange, and tweeters, but not woofers. If not, maybe I should start one? Just a thought. At least, whatever I build, I'll post my results.

10th June 2007, 11:31 PM	#1
Hara diyAudio Member Join Date: Oct 2005	Dipole Woofer for upper bass Recommendation Hello, I am going over revisions for my final dipole speaker design and I am lacking good choices for a good woofer with the following criteria. Low as possible distortion Used Bandwidth: (80-100, preferably low) - 250hz not including bandwidth for crossover slopes Linear output within used SPL SPL range: up to 105 db This tends to require drivers (using SL's dipole_spl excel sheets) with a bare minimum of 190 cm^2 surface area (or about 8" diameter) with 5mm of xmax. High xmax helps but consider the tradeoff of low distortion vs xmax. (http://www.zaphaudio.com/lowxmax.html) Driver size should be less than 15", preferably less. Sensitivity: Greater than 87db/watt*m Preferably Qts between .5 and .7 for simplified filter design Finally, Price: $30-$80 per driver Driver's Currently considered: Peerless SLS 12" and 10" ~$60 Dayton RS270 10" ~$30 Any suggestions or data on such drivers would be greatly appreciated.

11th June 2007, 06:05 PM	#5
ScottG diyAudio Member Join Date: Feb 2003 Location: US	If I were you I wouldn't get "hung up" on low non-linear distortion, though sometimes audible with test tones - I personally find even fairly high non-linear distortion to be in-audible for music (order vs. spl dependent). I use two of these per side parallel connected (i.e. 8 ohms nominal): http://www.shredmuzic.com/product_p/813-010.htm I have no idea what the distortion spectrum/level is like with them.. however: 1. They sound good in this application, 2. They are limited in fs - allowing for lower nominal distortion when considering excursion, 3. 2 drivers are better than one (..again, lower nominal distortion), 4. They have more mass - which provides a bit more "punch" in this region (..though marginally at the expense of "delicacy" depending on the pairing amplifier), Caution: The drivers have 3 inch VC's - this may allow for less distortion near fs (and they are also vented), but conversely more distortion at higher freq.s (>1 kHz). Additionally, IF you purchase them - make sure to "test" the drivers with various music to make sure you don't get a driver with poor gluing at the surround that makes a buzzing sound (..one of my 4 drivers did this prior to modification to fix it - of course you can always return the driver for a new one). __________________ perspective is everything

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10th June 2007, 11:34 PM	#2
bigwill diyAudio Member Join Date: Dec 2004 Location: UK	I know it's 15" but consider the Eminence Beta 15 Qts of around 0.6 iirc, senstivity around 98dB xmax of 4mm, but it's 15" Fs of 35Hz so It should easily cover the range you want Quite a linear response in the range you want too

10th June 2007, 11:43 PM	#3
Hara diyAudio Member Join Date: Oct 2005	Thank you for your response. Do you have any data on its harmonic distortion or links to people who have tested them?

11th June 2007, 08:39 PM	#6
Hara diyAudio Member Join Date: Oct 2005	I'm concerned for low harmonic distortion measurements simply because the other drivers used in my design are also quite low. Vifa XG18, and Seas H1212. So for the sake of matching well together I thought it would be a good idea to also have low distortion woofers. Also for comparison reasons, having more numbers helps. They are relatively cheap drivers so going two per cabinet allows me to go even lower down to 50-60hz which is a nice benefit, but not a requirement. I checked madison's website, they do not provide complete datasheets on their drivers. While I'll be adding filters, it would be nice to know what kind of filters they would need. (From the given parameters, I just ran it through winISD in a large box to see its response, and it does look good for this application.) I will of course be testing the purchased drivers (whichever I choose) for final consideration. Anyways, thank you for your suggestion ScottG, it looks like a good candidate and will be considered. I have basically till the end of next week to decide, just so I can start working on it. Also, is there any woofer testing site that compare many woofers around this range? I know there are a few for the subwoofer range, midrange, and tweeters, but not woofers. If not, maybe I should start one? Just a thought. At least, whatever I build, I'll post my results.