Sensitivity training

tcaster · 14th March 2010, 11:55 PM

I now have P Audio coaxials in my K15 Karlsons with the aim of also using the cabs as the bass driver in a 3 way set up with an active crossover.
My P Audio BM15CXAs are rated at 101db for the woofer/106db for the tweeter spl@1m.
I want to bypass the tweeter and use just the coaxial woofer in the K15 with a separate midrange cab and tweeter on top of that.
I would like to know if matching the sensitivity of the mid driver to the woofer(or tweeter) is as big of an issue if I'm using an active crossover with attenuation capabilities for each of the three bands.
My Amt-1 tweeters are 92db spl@1m
I already have a pair of Focal6W252B 6.5 midrange drivers that fit right into my mid cabs now.They're sensitivity is 88.3db@1w1m
It was recomended to get the Audax PR170MO 6.5s with their closer 100db sensitivity.
I would have to alter my cutouts on the cabs to install them however.
Can I just try the lower sensitivity Focal 6.5s and attenuate the woofers/tweeters with the crossovers to match volumes or does the sensitivity have to match much closer than 88.3 vs 101db even with an active crossover (Linkwitz Riley 24db Carvin 3 way stereo crossover).
I'll be using this system in a 15 x20 room. Amps are older Bryston 2bs all around (two amps bridged for each of the woofers)
Thanks for your help.

tinitus · 15th March 2010, 12:04 AM

I would find a mid driver that matches you 92db AMT
You need to calculate with BSC in the midbass
Avarage 94db seems a good target

tcaster · 15th March 2010, 12:06 AM

Thanks, I'm a novice what is BSC?

Glowbug · 15th March 2010, 01:32 AM

Baffle step correction

doug20 · 15th March 2010, 12:55 PM

Quote:

Originally Posted by tinitus

I would find a mid driver that matches you 92db AMT
You need to calculate with BSC in the midbass
Avarage 94db seems a good target

B&C 6MD38 or PHL 1120 might be a great match for that both are in the 94dB sensitivity area.

tcaster · 15th March 2010, 09:41 PM

My pre made mid cabs are actually sealed surround type cabs.They are 18" wide,10" deep, and 8"tall with a 6.5" woofer and two 4" tweeters on either side.
I'm going to plug the tweeter cutouts.They are shaped like Bose(orange section like) etc.so there will be more baffle out to the sides wrapping around to the rear and there is plenty of room to slide them back and forward on top of the Karlsons for my hillbilly BSC adjustments.
I've read that the Audax PR170MO have over rated sensitivity specs (more like 95-96db) so maybe they'll be in the range no?
My experience with Neodynium magnets is with guitar amp speakers and while they are light and efficient they seem harsher to me.
The PHL1120s seem like top notch units but them mounting would be tricky as while their screw holes are out about 7.4 inches the rest of the actual rim is less than 6.5" and my cab openings are 6.5".
If I can't find speakers that will drop right in my 165mm (6.5") lipped openings I'd prefer to have them overlap all the way around and surface mount them.
Does any one think the Audax PM17 would be a poorer choice compared to the PHL1120?
Thanks again for any and all advice.

14th March 2010, 11:55 PM	#1
tcaster diyAudio Member Join Date: Nov 2009	Sensitivity training I now have P Audio coaxials in my K15 Karlsons with the aim of also using the cabs as the bass driver in a 3 way set up with an active crossover. My P Audio BM15CXAs are rated at 101db for the woofer/106db for the tweeter spl@1m. I want to bypass the tweeter and use just the coaxial woofer in the K15 with a separate midrange cab and tweeter on top of that. I would like to know if matching the sensitivity of the mid driver to the woofer(or tweeter) is as big of an issue if I'm using an active crossover with attenuation capabilities for each of the three bands. My Amt-1 tweeters are 92db spl@1m I already have a pair of Focal6W252B 6.5 midrange drivers that fit right into my mid cabs now.They're sensitivity is 88.3db@1w1m It was recomended to get the Audax PR170MO 6.5s with their closer 100db sensitivity. I would have to alter my cutouts on the cabs to install them however. Can I just try the lower sensitivity Focal 6.5s and attenuate the woofers/tweeters with the crossovers to match volumes or does the sensitivity have to match much closer than 88.3 vs 101db even with an active crossover (Linkwitz Riley 24db Carvin 3 way stereo crossover). I'll be using this system in a 15 x20 room. Amps are older Bryston 2bs all around (two amps bridged for each of the woofers) Thanks for your help.

15th March 2010, 01:32 AM	#4
Glowbug diyAudio Member Join Date: Feb 2006 Location: Hillsborough, NC/McLean, VA	Baffle step correction __________________ Jim J.

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15th March 2010, 12:04 AM	#2
tinitus diyAudio Moderator Join Date: Nov 2005	I would find a mid driver that matches you 92db AMT You need to calculate with BSC in the midbass Avarage 94db seems a good target

15th March 2010, 12:06 AM	#3
tcaster diyAudio Member Join Date: Nov 2009	Thanks, I'm a novice what is BSC?

15th March 2010, 09:41 PM	#6
tcaster diyAudio Member Join Date: Nov 2009	My pre made mid cabs are actually sealed surround type cabs.They are 18" wide,10" deep, and 8"tall with a 6.5" woofer and two 4" tweeters on either side. I'm going to plug the tweeter cutouts.They are shaped like Bose(orange section like) etc.so there will be more baffle out to the sides wrapping around to the rear and there is plenty of room to slide them back and forward on top of the Karlsons for my hillbilly BSC adjustments. I've read that the Audax PR170MO have over rated sensitivity specs (more like 95-96db) so maybe they'll be in the range no? My experience with Neodynium magnets is with guitar amp speakers and while they are light and efficient they seem harsher to me. The PHL1120s seem like top notch units but them mounting would be tricky as while their screw holes are out about 7.4 inches the rest of the actual rim is less than 6.5" and my cab openings are 6.5". If I can't find speakers that will drop right in my 165mm (6.5") lipped openings I'd prefer to have them overlap all the way around and surface mount them. Does any one think the Audax PM17 would be a poorer choice compared to the PHL1120? Thanks again for any and all advice.

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