I have a question for you...

Tripmaster · 2nd August 2008, 11:43 AM

Hi all

My father has given me two SEAS 8” P21REX H282 woofers

http://www.seas.no/images/stories/vi...282_p21rex.pdf

and two SEAS 25 TAF/G tweeters with crossovers.

Does anyone know what these units are like, and if they are OK can recommend a suitable enclosure/crossover?

I think they were purchased from http://www.iplacoustics.co.uk/ several years ago

Thanks

Trip

Tripmaster · 2nd August 2008, 11:56 AM

Here are some photos

Tripmaster · 2nd August 2008, 11:57 AM

and another

Tripmaster · 2nd August 2008, 11:59 AM

one more

Tripmaster · 2nd August 2008, 04:44 PM

I plan to pair these speakers with a LM3886 dual mono Chipamp with 2x 300va, twin 25v secondaries. The sensitivity of the woofers are reasonable at 91db.

Would these drivers be suitable for an open baffle design?

I am open to suggestions.

MarcelvdG · 2nd August 2008, 05:19 PM

I have no experience with these loudspeakers at all, but the QTS value of 0.37 seems to make them very suitable for vented boxes (bass reflex boxes). It is quite close to the Q you need for a fourth-order Butterworth alignment. With a fourth-order Butterworth bass reflex design, the -3 dB point would be equal to the free resonance frequency of 33 Hz, if I remember it correctly.

If you put them on an extremely large open baffle or in an extremely large closed box, you get a -3 dB point of about 77.7 Hz. Since you also get a slow bass roll-off below that frequency, you can correct for that electronically to some extent.

With a closed box aligned for second-order Butterworth response, the -3 dB point becomes 63.1 Hz.

Best regards,
Marcel van de Gevel

TimA · 2nd August 2008, 05:42 PM

I know both these units quite well. The tweeter is smooth-sounding and refined. The P21REX (in my opinion) can be a little difficult to work with in that it is not easy to get decent bass from in it in a ported enclosure, despite encouraging simulations. In a transmission-line design it can be very good - natural, with good bass extension.

Tim.

Tripmaster · 2nd August 2008, 06:15 PM

Quote:

Originally posted by TimA
I know both these units quite well. The tweeter is smooth-sounding and refined. The P21REX (in my opinion) can be a little difficult to work with in that it is not easy to get decent bass from in it in a ported enclosure, despite encouraging simulations. In a transmission-line design it can be very good - natural, with good bass extension.

Tim.

What would you suggest I do with them? What would you pair with the tweeter?

Nuuk · 2nd August 2008, 06:21 PM

I'll hazard a guess that they came from an (early) IPL TL speaker kit. If they do, Ivan Leslie may even let you have the cabinet design.

PB2 · 2nd August 2008, 06:32 PM

I believe that they were also used in the Signet SL-280, or perhaps similar versions.

Pete B.

2nd August 2008, 11:43 AM	#1
Tripmaster diyAudio Member Join Date: Feb 2008 Location: UK	I have a question for you... Hi all My father has given me two SEAS 8” P21REX H282 woofers http://www.seas.no/images/stories/vi...282_p21rex.pdf and two SEAS 25 TAF/G tweeters with crossovers. Does anyone know what these units are like, and if they are OK can recommend a suitable enclosure/crossover? I think they were purchased from http://www.iplacoustics.co.uk/ several years ago Thanks Trip

2nd August 2008, 06:21 PM	#9
Nuuk diyAudio Member Join Date: Feb 2003 Location: Somerset, SW England	I'll hazard a guess that they came from an (early) IPL TL speaker kit. If they do, Ivan Leslie may even let you have the cabinet design. __________________ The truth need not be veiled, for it veils itself from the eyes of the ignorant.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
newbie with input tran. question and wiring question	imo	Solid State	0	18th January 2006 10:10 PM
Capacitor Question /question on cap	TunaFish	Tubes / Valves	14	12th January 2004 02:23 AM
PS question - tformer question actually	breguetphile	Chip Amps	2	30th May 2003 01:29 PM
old speaker question, bullet midrange question & link to speaker project	wallijonn	Multi-Way	10	5th November 2002 06:03 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

2nd August 2008, 04:44 PM	#5
Tripmaster diyAudio Member Join Date: Feb 2008 Location: UK	I plan to pair these speakers with a LM3886 dual mono Chipamp with 2x 300va, twin 25v secondaries. The sensitivity of the woofers are reasonable at 91db. Would these drivers be suitable for an open baffle design? I am open to suggestions.

2nd August 2008, 05:19 PM	#6
MarcelvdG diyAudio Member Join Date: Mar 2003 Location: Haarlem, the Netherlands	I have no experience with these loudspeakers at all, but the QTS value of 0.37 seems to make them very suitable for vented boxes (bass reflex boxes). It is quite close to the Q you need for a fourth-order Butterworth alignment. With a fourth-order Butterworth bass reflex design, the -3 dB point would be equal to the free resonance frequency of 33 Hz, if I remember it correctly. If you put them on an extremely large open baffle or in an extremely large closed box, you get a -3 dB point of about 77.7 Hz. Since you also get a slow bass roll-off below that frequency, you can correct for that electronically to some extent. With a closed box aligned for second-order Butterworth response, the -3 dB point becomes 63.1 Hz. Best regards, Marcel van de Gevel

2nd August 2008, 05:42 PM	#7
TimA diyAudio Member Join Date: Nov 2002 Location: UK	I know both these units quite well. The tweeter is smooth-sounding and refined. The P21REX (in my opinion) can be a little difficult to work with in that it is not easy to get decent bass from in it in a ported enclosure, despite encouraging simulations. In a transmission-line design it can be very good - natural, with good bass extension. Tim.

2nd August 2008, 06:32 PM	#10
PB2 diyAudio Member Join Date: Sep 2004 Location: North East Blog Entries: 1	I believe that they were also used in the Signet SL-280, or perhaps similar versions. Pete B.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)