When you say reference levels, are you referring to something like THX certified reference levels? That is a difficult standard to meet for most home audio gear.
THX reference levels specify that a -20dB of full scale pink noise input to the amp should produce 85dB (C) at the listening position (in this case 2m). That means that at 1m distance, the driver needs to produce 85dB + 6dB or 91dB. Also the peak levels need to be capable of hitting 105dB at 2m or 111dB at 1m. These are a tall order for any driver, let alone full range drivers. You will need pro audio drivers to do this, and the only ones that will do this with ability to get to 80Hz are probably coaxial drivers in the 6in to 8in class. Take for example a B&C 6FHX51, which has 93dB sensitivity and 300w peak power handling and 85Hz frequency range (will need a vented cabinet).
B&C Speakers
or the 8 inch variant with 94dB sensitivity and 75Hz extension:
B&C Speakers
If you relaxed the requirement to bass extension of 170Hz, then a PRV 5MR450-NDY can probably do it as a fullrange (non-coaxial) driver in a sealed cabinet.
THX reference levels specify that a -20dB of full scale pink noise input to the amp should produce 85dB (C) at the listening position (in this case 2m). That means that at 1m distance, the driver needs to produce 85dB + 6dB or 91dB. Also the peak levels need to be capable of hitting 105dB at 2m or 111dB at 1m. These are a tall order for any driver, let alone full range drivers. You will need pro audio drivers to do this, and the only ones that will do this with ability to get to 80Hz are probably coaxial drivers in the 6in to 8in class. Take for example a B&C 6FHX51, which has 93dB sensitivity and 300w peak power handling and 85Hz frequency range (will need a vented cabinet).
B&C Speakers
or the 8 inch variant with 94dB sensitivity and 75Hz extension:
B&C Speakers
If you relaxed the requirement to bass extension of 170Hz, then a PRV 5MR450-NDY can probably do it as a fullrange (non-coaxial) driver in a sealed cabinet.
Yes, you are in a different ball game now and the possibility of a full range driver is definitely there. You actually have lots of options at these levels - no problem as many drivers are 85dB or more efficient. Many decent 4in full range mounted in a wall mount bass reflex or a flat folded MLTL can reach 80Hz and get to 101dB. I will see what I can come up with but I have looked at this before.
Design for Flat Wall Mount MLTL for A7.3
Here is a design that can reach 102dB with flat extension to 80Hz. It is a 15x15in "pizza box" shaped speaker with 2.75in depth. Use 1.5in dia SCH40 PVC pipe for the vent. Since it is wall mount, there is no baffle step correction needed. Use with a second order -12dB/oct high pass filter at 120Hz to prevent cone over excursion.
Use polyfill stuffing from closed end to just past driver.
Freq response at xmax (with 120 Hz -12dB HPF):
Cone excursion at 13.7 volts for xmax:
Impedance:
Electrical Power at xmax:
Impulse Response:
And by the way, if you make the vent 4 in long and remove the HPF, you can use this as a fullrange speaker but at lower SPL's and get some pretty good bass extension to 45Hz:
Here is a design that can reach 102dB with flat extension to 80Hz. It is a 15x15in "pizza box" shaped speaker with 2.75in depth. Use 1.5in dia SCH40 PVC pipe for the vent. Since it is wall mount, there is no baffle step correction needed. Use with a second order -12dB/oct high pass filter at 120Hz to prevent cone over excursion.
Use polyfill stuffing from closed end to just past driver.
Freq response at xmax (with 120 Hz -12dB HPF):
Cone excursion at 13.7 volts for xmax:
Impedance:
Electrical Power at xmax:
Impulse Response:
And by the way, if you make the vent 4 in long and remove the HPF, you can use this as a fullrange speaker but at lower SPL's and get some pretty good bass extension to 45Hz:
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You wanted a wall mount so I made it thin. This lends itself to a MLTL. A bass reflex will not sound as nice and not load the cone as well. Yes, Mark Audio Alpair 7.3. I picked it because it has one of the larger xmax (4mm) for a 4in driver. You need that xmax to get 101dB at 80Hz if your driver is 85dB sensitive. A CHR70 cost less and works very similar but will not get to 101dB before running out of xmax. You can attach this out to a long 45in tall flat stick and it will behave almost the same.
Are there any other drivers that would work as well?
I've seen that the Alpair 7.3 has a very strange off axis behavior (very narrow between 6-7kHz and blooming around 10kHz).
Maybe something even bigger like 8". Dispersion might not be good for multiple seats but would work for a single seat while reducing off axis energy sent into the room?
Thanks Studio Au. I did search for user "Overkill Audio" and "BMR" but nothing matching my requirements came up. Do you have a direct link? Thanks!
I have not heard one in person but you will find many folks in this forum who think the A7.3 as one of the best sounding drivers period. It does have some HF response that has been subject of debate in some threads but from what I have heard regarding user impressions - you won't notice those peaks and dips.
You actually have better polar dispersion with a smaller driver so moving to a larger size makes things worse. An 8 in driver has a narrow "beaming" effect. It has to do with larger radiators have narrower beam width.
Main reason I picked A7.3 was for the 4mm xmax which helps it reach higher SPL levels with a high pass filter.
Does this design seem good from aesthetics and performance standpoint? One good thing about my earlier comment about pro audio coaxials is that their HF directivity is controlled with a horn. In the case of the B&C driver in mentioned the horn is external and may work quite well for this purpose.
I don't believe in magic and I don't believe there're audible characteristics of a driver that can't be measured. So less distortion is good and less directivity problems is also good.
If high frequency blooming (like in the Markaudio Alpair 7.3) sounds good to some then that is just their preference (maybe they compensate for age-related hearing loss?). Nothing wrong with that but it's also certainly nothing that makes the driver more accurate. Music and movies aren't mixed on speakers that have an irregular off axis response.
As I've said before, a beaming 8" might help decrease reflection levels. Certainly something desirable in a home theater application. On the other hand a 8" driver might only work for a single seat because of beaming.
Are there any good 8" candidates that are smooth in the listening window for a single seat?
I have a parametric equalizer so I'm not limited to drivers that would only work with passive crossover networks.
There is the Dayton PS-220 that has the SPL capability you seek as it is 95dB sensitive. It can probably be EQ'd smooth if you have PEQ. Are you ok with that one? Look at the curve and specs and if you like it I can design a box for HT around it for you. The Tang Band W8-1772 is also worth looking at.
Would you be opposed to a 80Hz to 9kHz "semi-fullrange" and letting a super tweeter cover above 9kHz? Most vocals, spatial cues, etc are covered in this range. If you are ok with his approach there is a 100dB sensitive 8in pro audio driver from PRV that is in the same family as the 5MR450-NDY that I really like. I would recommend that but it doesn't reach 80Hz easily. Here is the driver I am talking about: http://www.parts-express.com/prv-audio-8mr500-ndy-4-8-neodymium-midrange-woofer-4-ohm--294-2708?utm_source=google&utm_medium=cpc&utm_campaign=pla
Would you be opposed to a 80Hz to 9kHz "semi-fullrange" and letting a super tweeter cover above 9kHz? Most vocals, spatial cues, etc are covered in this range. If you are ok with his approach there is a 100dB sensitive 8in pro audio driver from PRV that is in the same family as the 5MR450-NDY that I really like. I would recommend that but it doesn't reach 80Hz easily. Here is the driver I am talking about: http://www.parts-express.com/prv-audio-8mr500-ndy-4-8-neodymium-midrange-woofer-4-ohm--294-2708?utm_source=google&utm_medium=cpc&utm_campaign=pla
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On or in wall line array
Hi Spekr,
My Overkill Audio designs from a decade ago are not relevant to the modern world...Massive, heavy, expensive, complex and amazing sound....Geeks loved them the real world dont!
You hit the nail on the head, you are looking for the same solution as 95% of all middle to high income folks....Great sounding low profile on-wall or in-wall AV solutions.
I have posted a lot of info and pictures over the last few years on this site so if you trawl back over my posts you will find a lot of good info on how I believe it should be done. Disclaimer...Many disagree with me on this site....They are all wrong!
I will have some cool " Bamboo and BMR" DIY kits available in December
(depending on shipping from China) and the attached should help to explain a bit more about the advantages of on wall BMR loudspeakers.
My website wont be ready until November but I have put up some "sneak previews" here CustomInstallAudio
I don't think there is any USA distribution for the good audiophile BMR's ( ignore the Parts Express BMR's.....Only TV screen audio grade) so it may be a non starter for you at the moment. But its still an interesting subject.
Hope this helps and all the best
Derek.
Hi Spekr,
My Overkill Audio designs from a decade ago are not relevant to the modern world...Massive, heavy, expensive, complex and amazing sound....Geeks loved them the real world dont!
You hit the nail on the head, you are looking for the same solution as 95% of all middle to high income folks....Great sounding low profile on-wall or in-wall AV solutions.
I have posted a lot of info and pictures over the last few years on this site so if you trawl back over my posts you will find a lot of good info on how I believe it should be done. Disclaimer...Many disagree with me on this site....They are all wrong!
I will have some cool " Bamboo and BMR" DIY kits available in December
(depending on shipping from China) and the attached should help to explain a bit more about the advantages of on wall BMR loudspeakers.
My website wont be ready until November but I have put up some "sneak previews" here CustomInstallAudio
I don't think there is any USA distribution for the good audiophile BMR's ( ignore the Parts Express BMR's.....Only TV screen audio grade) so it may be a non starter for you at the moment. But its still an interesting subject.
Hope this helps and all the best
Derek.
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