I’m looking for a pair of good, moderate price, high efficiency dynamic drivers, covering higher mid – lower treble, and the most often mentioned is the 100 dB Audax PR170M0.
Others are the Eminence Beta 8 and 10, JBL 2123, PHL 3451, Ciare PM250, some Supravox and the PHL 1040 & 1060 (yes different size > different response patterns).
Audax is now made by AAC, and the PR170M0 is back on the market for US $ 70 at Madisound:
www.madisound.com/cgi-bin/index.cgi?cart_id=1765800.22568&pid=107 with as before “100 dB efficiency”. .
I ran the Madisound specs through Unibox though, and the maximum SPL at 2.83 Vrms 1m was only 94.4 dB!
In deference to the driver, the nearest spec driver, the “100 dB” PHL 1040 came in at 99.4 dB, but that’s only 0.6 dB down, not 5.6 dB down!!
What’s happening, revised specs/ mistake at Madisound??
Thanks
Others are the Eminence Beta 8 and 10, JBL 2123, PHL 3451, Ciare PM250, some Supravox and the PHL 1040 & 1060 (yes different size > different response patterns).
Audax is now made by AAC, and the PR170M0 is back on the market for US $ 70 at Madisound:
www.madisound.com/cgi-bin/index.cgi?cart_id=1765800.22568&pid=107 with as before “100 dB efficiency”. .
I ran the Madisound specs through Unibox though, and the maximum SPL at 2.83 Vrms 1m was only 94.4 dB!
In deference to the driver, the nearest spec driver, the “100 dB” PHL 1040 came in at 99.4 dB, but that’s only 0.6 dB down, not 5.6 dB down!!
What’s happening, revised specs/ mistake at Madisound??
Thanks
Hi Rick,
I just pulled my Audax spec sheet (not looked at for about 9years).
Penned in beside the 100db sensitivity is a little 93.5 ?
I think I used the T/S params to check the sensitivity figures Audax quoted.
All the others (12) I checked at that time came very close to the printed figure, usually about 0.1db to 0.6db below spec.
I bought the HM210co & HM130co to go with their HD-3P.
I just pulled my Audax spec sheet (not looked at for about 9years).
Penned in beside the 100db sensitivity is a little 93.5 ?
I think I used the T/S params to check the sensitivity figures Audax quoted.
All the others (12) I checked at that time came very close to the printed figure, usually about 0.1db to 0.6db below spec.
I bought the HM210co & HM130co to go with their HD-3P.
Hi,
I do not have the calcs nor can I remember which formuale I used but my penned in figure appears to disagree with their quoted sensitivity.
Based on their T/S numbers I think they are kidding us.
There are about 50 speakers in the spec sheet. I only checked 13 that I was interested in. This was the only one of the thirteen that showed a major discrepancy.
I do not have the calcs nor can I remember which formuale I used but my penned in figure appears to disagree with their quoted sensitivity.
Based on their T/S numbers I think they are kidding us.
There are about 50 speakers in the spec sheet. I only checked 13 that I was interested in. This was the only one of the thirteen that showed a major discrepancy.
Gents,
I'm using a pair of the audax PR170m0s in my open baffle project. Their measured sensativity was 97-98db across the passband 250-2.5K using speaker workshop...
The 100db youy see quoted is optimistic if you run the speaker up into the controlled breakup region to get more HF extension ...
Even at "only" 98db they were a perfect match for my ribbon tweeters. The sound is very dynamic and vocals sound effortless. The biggest problem if you plan to run these midranges is that they have to be cross pretty high >350hz or very steep 4th order ot better if you want to go lower because of their very low excursion. These are not mid-bass drivers but pure midranges..
Regards.
--Chris
I'm using a pair of the audax PR170m0s in my open baffle project. Their measured sensativity was 97-98db across the passband 250-2.5K using speaker workshop...
The 100db youy see quoted is optimistic if you run the speaker up into the controlled breakup region to get more HF extension ...
Even at "only" 98db they were a perfect match for my ribbon tweeters. The sound is very dynamic and vocals sound effortless. The biggest problem if you plan to run these midranges is that they have to be cross pretty high >350hz or very steep 4th order ot better if you want to go lower because of their very low excursion. These are not mid-bass drivers but pure midranges..
Regards.
--Chris
I have no knowledge about the driver in question, but it sounds to me as if one is measured in half space (ie mounted in a wall) and the other is in free space (mounted in a free standíng box).
The difference between the two conditions would be 6 dB for low frequencies. Loudspeaker driver sensitivity is mostly stated in half space, simulation software taking the baffle step into account should simulate in free space for low frequencies to make sense.
The difference between the two conditions would be 6 dB for low frequencies. Loudspeaker driver sensitivity is mostly stated in half space, simulation software taking the baffle step into account should simulate in free space for low frequencies to make sense.
KYW
As we are talking about output above the bass region, I think you are most correct – that SPL is determined by many factors other than T/S Parameters.
What are the other midrange SPL factors; and
Can it be determined without testing ~ before buying ~ which drivers are meant to be operated significantly above there resonance?
Thanks
As we are talking about output above the bass region, I think you are most correct – that SPL is determined by many factors other than T/S Parameters.
What are the other midrange SPL factors; and
Can it be determined without testing ~ before buying ~ which drivers are meant to be operated significantly above there resonance?
Thanks
vs Kevlar
Or how might the paper PR170M0 compare sonically with high (higher?) efficiency Focal Kevlar mids eg the Focal 7k6411
www.zalytron.com/Specs/7K6411.pdf ?
The Audax has just 0.5 mm Xmax, the Focal 2 mm. So it could probably be crossed about an octave lower
~ but the $64k question ~ how easy to control the break-ups of either??
Or how might the paper PR170M0 compare sonically with high (higher?) efficiency Focal Kevlar mids eg the Focal 7k6411
www.zalytron.com/Specs/7K6411.pdf ?
The Audax has just 0.5 mm Xmax, the Focal 2 mm. So it could probably be crossed about an octave lower
~ but the $64k question ~ how easy to control the break-ups of either??
Hi,
the Focal & Audax read nearly the same.
Looking at the graph and using Qts to determine the lowest usable frequency, the range available seems to be 180Hz to 2kHz and possibly 2.5kHz.
A notable exception between the specs is Le 0.3mH Focal & 0.7mH Audax . If the Focal coil is about 10mm long cf 7mm Audax, why/how can the inductance be so much lower?
Both are single layer and Re = 6r5 to 6r2 indicating similar wire size & turns. The Focal must have thicker wire and more turns to give this result.
the Focal & Audax read nearly the same.
Looking at the graph and using Qts to determine the lowest usable frequency, the range available seems to be 180Hz to 2kHz and possibly 2.5kHz.
A notable exception between the specs is Le 0.3mH Focal & 0.7mH Audax . If the Focal coil is about 10mm long cf 7mm Audax, why/how can the inductance be so much lower?
Both are single layer and Re = 6r5 to 6r2 indicating similar wire size & turns. The Focal must have thicker wire and more turns to give this result.
Hi,
Yo could be right(?) Pardon my ignorance, but:
> Looking at the graph
The Focal 7K6411 graph is at www.zalytron.com/Specs/7K6411.pdf
Where is a PR170M0 FR graph (preferably of comparable detail and smoothing)?
> using Qts to determine the lowest usable frequency,
Audax I believe recommended a minimum of 500 Hz. Why Qts?
Cheers
Yo could be right(?) Pardon my ignorance, but:
> Looking at the graph
The Focal 7K6411 graph is at www.zalytron.com/Specs/7K6411.pdf
Where is a PR170M0 FR graph (preferably of comparable detail and smoothing)?
> using Qts to determine the lowest usable frequency,
Audax I believe recommended a minimum of 500 Hz. Why Qts?
Cheers
Hi,
Qts determines the ratio of box size to Vas and the ratio of Fb and F-3 to Fs.
For a particular driver with a fixed Qts then by selecting an appropriate Qtc (of a completed box speaker) you end up with an F-3 that is variable over only a small range. Useable Qtc values range from 0.5 to 0.9, outside these you are into the realms of deliberating tailoring the bass (in this case mid) response to achieve a false sense of low end extension. If I were designing a mid speaker I would restrict my range of Qtc to 0.6 to 0.75.
I plugged the Focal numbers into an Excel spreadsheet for you.
My guess of 180Hz was unfounded, it turns out to be 192Hz.
For a Qts of 0.43 the F-3 frequencies are, 0.5>=211Hz, 0.6>=197Hz, 0.71>=192Hz, 0.8>=195Hz, 0.9>=203Hz, 1.0>=214Hz.
All the Qtc values from 0.71 downwards have a smoothly falling response from the flat region ultimately achieving -12db/octave for these sealed box examples. At Qtc=0.71 the fall in response is Butterworth and at Qtc=0.5 the response is Bessel.
All the Qtc values above 0.71 have a slight hump in the response becoming worse as Qtc rises. The hump at Qtc=1 ~=+1.2db. I think this would be noticeable as coloration in your midband and personally I would avoid it. However if you have the facility to experiment with box sizes then it could be fruitfull in the end result.
Qts determines the ratio of box size to Vas and the ratio of Fb and F-3 to Fs.
For a particular driver with a fixed Qts then by selecting an appropriate Qtc (of a completed box speaker) you end up with an F-3 that is variable over only a small range. Useable Qtc values range from 0.5 to 0.9, outside these you are into the realms of deliberating tailoring the bass (in this case mid) response to achieve a false sense of low end extension. If I were designing a mid speaker I would restrict my range of Qtc to 0.6 to 0.75.
I plugged the Focal numbers into an Excel spreadsheet for you.
My guess of 180Hz was unfounded, it turns out to be 192Hz.
For a Qts of 0.43 the F-3 frequencies are, 0.5>=211Hz, 0.6>=197Hz, 0.71>=192Hz, 0.8>=195Hz, 0.9>=203Hz, 1.0>=214Hz.
All the Qtc values from 0.71 downwards have a smoothly falling response from the flat region ultimately achieving -12db/octave for these sealed box examples. At Qtc=0.71 the fall in response is Butterworth and at Qtc=0.5 the response is Bessel.
All the Qtc values above 0.71 have a slight hump in the response becoming worse as Qtc rises. The hump at Qtc=1 ~=+1.2db. I think this would be noticeable as coloration in your midband and personally I would avoid it. However if you have the facility to experiment with box sizes then it could be fruitfull in the end result.
I've worked extensively with PR170M0s and variants (PR17HR70, PR17HR100).
I too, would limit low end extension to no lower than 400 Hz, 18 dB/oct, or 500 Hz, 12 dB/oct. IME, for a more "public address" application (which is where these drivers see their most usage, ie, in several EAW and Peavey high-end cabinets... Audax OEM supplied the PR17 to these manufacturers, among others), a range of 500-5000 Hz is QUITE usable... I tend to use these drivers in a small enclosure (Qtc of about .8 to 1.0), with a silght overlap between the woofer and midrange, and a slight "underlap" (gap) between the midrange and tweeter. Also, using a slightly lower-Q low-pass (ie, larger inductor and smaller cap) on the top end of the PR170, will also benefit the response greatly. For the most part, if you use the tricks specified, the response will wind up pretty much ruler-flat. .. the "rising response" will be very well compensated for. Exemplary dynamic range and control...
For a "hi-fi" application, using them in the range of about 400-3200 Hz (three octave spread) would be quite nice. Avoids most of the breakup, and what you do get, does not color the sound to any detectable amount. GREAT driver. My first choice for high-efficiency 3-way systems, even to this day...
Regards,
Gordon.
I too, would limit low end extension to no lower than 400 Hz, 18 dB/oct, or 500 Hz, 12 dB/oct. IME, for a more "public address" application (which is where these drivers see their most usage, ie, in several EAW and Peavey high-end cabinets... Audax OEM supplied the PR17 to these manufacturers, among others), a range of 500-5000 Hz is QUITE usable... I tend to use these drivers in a small enclosure (Qtc of about .8 to 1.0), with a silght overlap between the woofer and midrange, and a slight "underlap" (gap) between the midrange and tweeter. Also, using a slightly lower-Q low-pass (ie, larger inductor and smaller cap) on the top end of the PR170, will also benefit the response greatly. For the most part, if you use the tricks specified, the response will wind up pretty much ruler-flat. .. the "rising response" will be very well compensated for. Exemplary dynamic range and control...
For a "hi-fi" application, using them in the range of about 400-3200 Hz (three octave spread) would be quite nice. Avoids most of the breakup, and what you do get, does not color the sound to any detectable amount. GREAT driver. My first choice for high-efficiency 3-way systems, even to this day...
Regards,
Gordon.
Yep, first breakup on a 6" driver is usually around 1600 Hz or so. But, from the data I've collected using this driver, the breakup is very benign... and doesn't really begin to color the sound, until well above 3KHz. In fact, even using it up to 5KHz... the dispersion is more of a sonic factor (ie beaming) than breakup... to a LARGE margin...
Regards,
Gordon.
Regards,
Gordon.
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