Audax PR170M0 –100 dB or just *94 dB??

[rick57]

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:
http://www.madisound.com/cgi-bin/ind....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

[jpw2]

I have a pair of these drivers by audax. I am currently building a speaker with them. I measured them and there is a wide db range in its frequency response. However I was listening to them without a crossover and they sound realy nice. You will not get much out of them below 300Hz.

[rick57]

I can live with not much below 300Hz; but have you modelled them & if so what sensitivity did you get?

Cheers

[AndrewT]

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.

[rick57]

Andrew

> I think I used the T/S params to check the sensitivity figures Audax quoted.

And did you get 100 db, or the penned in beside 93.5?

Thanks

[AndrewT]

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.

[rick57]

Ah, (should have realised) penned in by *you.
Shame on you Audax

[DIY_newbie]

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

[ThorstenL]

Konnichiwa,

Originally posted by rick57
I ran the Madisound specs through Unibox though, and the maximum SPL at 2.83 Vrms 1m was only 94.4 dB!

The PR170M0 is meant to be operated significantly above it's fundamental resonance. There the SPL is determined by many factors other than T/S Parameters. That said, I make it 97db/2.83V/1m and not 100db. Still much depends upon use as well.

Sayonara

[rick57]

The above makes sense, so they are only 2-3 db Optimistic.

Thanks guys