First real speaker project

kkosiba · 24th May 2007, 12:35 AM

Hello all,
I have been reading and lurking on this site for a few months now, and have decided to try my first real speaker project. I have built a couple of kit projects before, but nothing from scratch. I have a pair of SEAS P21RF/P 8" drivers from an old speaker and am planning on recycling it. I also have a pair of the Dayton PT2B-8 Planars that I would like to use in a two way. I know that feelings are pretty mixed on this tweeter, but it was cheap and was interested in trying a planar. Looking at the specs on both drivers(with limited understanding) it looks they could work. The Seas is pretty flat out to 3000Hz and the Dayton can be crossed at 3000 even 2500 if I use a third order crossover. My real question is can these two drivers work together, and what type of crossover would be recommended. I know these are very basic questions, but any advise/suggestions are greatly appreciated. I see the amazing talent at work on this site, and am always impressed, and inspired. thanks.

Kris

Jay_WJ · 24th May 2007, 04:45 AM

First off an 8" woofer and a planar ribbon tweeter are not a good combination for a 2 way design. I just looked at their FRs. Indeed they share a very narrow, just 1 octave range of flat response. Usually an 8" woofer needs a low xo point for a good result. Good off-axis performance is one reason. In your case you cannot go low due to the quick roll off of the planar.

I think the best bet is a higher order crossover at around 2300-2500 Hz. Why not try to simulate an XO net to get an idea?

Nanook · 24th May 2007, 05:43 AM

at the specs of the two drivers in question.
the overlap of the two are not very wide,

32-2.5K for the woof, 2k-26k for the tweeter. so an asymetric xover could work. Of more concern is the difference in efficiency, 88dB for the woof, 94 for the tweet...a 6dB difference is substantial.

do a search for a speaker project that uses these drivers.. but personally I wouldn't. A FR or close to FR 8" or larger may provide you with the efficiency and allow you to cross over at a higher frequency, well away from the tweeter resonances.

I would pick a different tweeter for use with that woofer, or a different woofer for that tweeter.

kkosiba · 25th May 2007, 01:16 PM

Thanks for the suggestions. I had a feeling that I was pushing it with that combination. I have never heard the dayton, but have read that it really isn't all that special, unless used in a line array. Maybe I will hang on to them for a appropriate project. I do though like the seas woofer. I am really wanting to try a planar, or ribbon tweeter. This does, I realize, present an efficiency problem, as most are far more efficient than most drivers. None the less are any suitable for use with this woofer. I have looked at the BG Neo 8, and the Aurum Cantus g2si, but again efficiency seems to be the big issue. all suggestions are appreciated.

Kris

sreten · 25th May 2007, 02:44 PM

http://www.zaphaudio.com/nondomes/

Hi,

the B&G c/o around 2kHz to your Seas woofer.

http://www.rjbaudio.com/Audiofiles/FRDtools.html

I do not see your problem regarding efficiency.
Just pad the tweeter level back to the mid level.

FWIW I think a Seas soft dome would suit the bass driver best .....

sreten.

kkosiba · 8th June 2007, 03:54 AM

It appears that the woofer I already have just isn't really suited to the planars. so I think I will save them for a more appropriate project. That being said, I now must call on people who have used the PT2B (or anybody who has an idea), what woofers work well with them. I was looking at the Hi-Vi F5, or F6 but don't know much about them. Thanks.

Kris

Jay_WJ · 8th June 2007, 04:05 AM

How about Seas CA18RNX? This 7" inch woofer can be crossed at as high as 3 kHz with no problem.

http://www.zaphaudio.com/6.5test/compare.html

Zaph also used this midwoofer for his Wave Guide TMM.

sreten · 8th June 2007, 03:13 PM

http://www.zaphaudio.com/5.5test/

Hi,

I'd say the TB W5-704S would be a good choice.

/sreten.

Jay_WJ · 8th June 2007, 03:56 PM

Quote:

Originally posted by sreten
http://www.zaphaudio.com/5.5test/

Hi,

I'd say the TB W5-704S would be a good choice.

/sreten.

I thought the same thing. If he wants a 5", the Tang Band will be a good choice. It'll give a better off-axis response. And it's cheap! But the Seas will give much better bass and has a bit lower distortion numbers.

sreten · 8th June 2007, 04:05 PM

Quote:

Originally posted by Jay_WJ

But the Seas will give much better bass and has a bit lower distortion numbers.

The point I think is the Seas deserves a better tweeter.
The W5 crossed over high will ameliorate some of the tweeter problems.

/sreten.

24th May 2007, 12:35 AM	#1
kkosiba diyAudio Member Join Date: Nov 2006	First real speaker project Hello all, I have been reading and lurking on this site for a few months now, and have decided to try my first real speaker project. I have built a couple of kit projects before, but nothing from scratch. I have a pair of SEAS P21RF/P 8" drivers from an old speaker and am planning on recycling it. I also have a pair of the Dayton PT2B-8 Planars that I would like to use in a two way. I know that feelings are pretty mixed on this tweeter, but it was cheap and was interested in trying a planar. Looking at the specs on both drivers(with limited understanding) it looks they could work. The Seas is pretty flat out to 3000Hz and the Dayton can be crossed at 3000 even 2500 if I use a third order crossover. My real question is can these two drivers work together, and what type of crossover would be recommended. I know these are very basic questions, but any advise/suggestions are greatly appreciated. I see the amazing talent at work on this site, and am always impressed, and inspired. thanks. Kris

24th May 2007, 05:43 AM	#3
Nanook diyAudio Member Join Date: Feb 2004 Location: Chinook Country.Alberta	I had a look... at the specs of the two drivers in question. the overlap of the two are not very wide, 32-2.5K for the woof, 2k-26k for the tweeter. so an asymetric xover could work. Of more concern is the difference in efficiency, 88dB for the woof, 94 for the tweet...a 6dB difference is substantial. do a search for a speaker project that uses these drivers.. but personally I wouldn't. A FR or close to FR 8" or larger may provide you with the efficiency and allow you to cross over at a higher frequency, well away from the tweeter resonances. I would pick a different tweeter for use with that woofer, or a different woofer for that tweeter. __________________ stew ☮ -"A sane man in an insane world appears insane."

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24th May 2007, 04:45 AM	#2
Jay_WJ diyAudio Member Join Date: Mar 2006 Location: Indiana	First off an 8" woofer and a planar ribbon tweeter are not a good combination for a 2 way design. I just looked at their FRs. Indeed they share a very narrow, just 1 octave range of flat response. Usually an 8" woofer needs a low xo point for a good result. Good off-axis performance is one reason. In your case you cannot go low due to the quick roll off of the planar. I think the best bet is a higher order crossover at around 2300-2500 Hz. Why not try to simulate an XO net to get an idea?

25th May 2007, 01:16 PM	#4
kkosiba diyAudio Member Join Date: Nov 2006	Thanks for the suggestions. I had a feeling that I was pushing it with that combination. I have never heard the dayton, but have read that it really isn't all that special, unless used in a line array. Maybe I will hang on to them for a appropriate project. I do though like the seas woofer. I am really wanting to try a planar, or ribbon tweeter. This does, I realize, present an efficiency problem, as most are far more efficient than most drivers. None the less are any suitable for use with this woofer. I have looked at the BG Neo 8, and the Aurum Cantus g2si, but again efficiency seems to be the big issue. all suggestions are appreciated. Kris

25th May 2007, 02:44 PM	#5
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	http://www.zaphaudio.com/nondomes/ Hi, the B&G c/o around 2kHz to your Seas woofer. http://www.rjbaudio.com/Audiofiles/FRDtools.html I do not see your problem regarding efficiency. Just pad the tweeter level back to the mid level. FWIW I think a Seas soft dome would suit the bass driver best ..... sreten.

8th June 2007, 03:54 AM	#6
kkosiba diyAudio Member Join Date: Nov 2006	It appears that the woofer I already have just isn't really suited to the planars. so I think I will save them for a more appropriate project. That being said, I now must call on people who have used the PT2B (or anybody who has an idea), what woofers work well with them. I was looking at the Hi-Vi F5, or F6 but don't know much about them. Thanks. Kris

8th June 2007, 04:05 AM	#7
Jay_WJ diyAudio Member Join Date: Mar 2006 Location: Indiana	How about Seas CA18RNX? This 7" inch woofer can be crossed at as high as 3 kHz with no problem. http://www.zaphaudio.com/6.5test/compare.html Zaph also used this midwoofer for his Wave Guide TMM.

8th June 2007, 03:13 PM	#8
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	http://www.zaphaudio.com/5.5test/ Hi, I'd say the TB W5-704S would be a good choice. /sreten.

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