Affordable Accuracy Monitor Review

[richard12511]

Preference Rating
SCORE: 5.3
SCORE w/sub: 8.0

Sensitivity: 83dB
View attachment 65634View attachment 65635View attachment 65636View attachment 65637View attachment 65638View attachment 65639

WOW! I know the scoring isn't a perfect metric, but WOW! This makes me really want to buy this speaker just to try this mod. This also really makes me want to try the BMR. It's obvious, Dennis really knows his stuff!

 

[Haint]

Dennis you're a wizard.

 

[Gatordaddy]

Wow, a modified pioneer with great subjective and objective performance at a stellar price. I never would have thought an inexpensive speaker with a small driver would impress Amirm in subjective listening tests. Congratulations to the designer.

I'm glad to see that "Andrew Jones Budget Speaker Apologists" and "Speaker Forum Rabbit-Hole Tweakers" can have a bit of well-deserved vindication.

@Dennis Murphy I will be ordering a pair of the updated version once I'm back from my next work assignment.

 

[goldark]

Amazing what can be done for the price. Dennis no longer makes speakers under Philharmonic Audio, but nearly all of Jim Salk's speakers are designed by Dennis, although unfortunately none in this price range. I have a pair of Salk WOW1 monitors on the way and may send to Amir to review.

 

[amirm]

P.S. @amirm and anyone looking at the graphs, the scaling is different from your usual(~40dB rather than 50), so the speaker doesn't look as flat as one would expect at a glance. Dunno if you want to redo the images but might be worth noting. The DI curves are also cut off.

Sorry. Fixed in the review.

 

[amirm]

Do you have the impedance/phase chart?

Yes, just added to the review.

 

[NakedRider]

Curious if this mod also works on the FS52 towers which are doing L/R duty in my home theater.

 

[MZKM]

Yes, just added to the review.

It is the exact same as the Pioneer, both the impedance and phase, you sure that's the AAM's plot?

 

[amirm]

It is the exact same as the Pioneer, both the impedance and phase, you sure that's the AAM's plot?

Oops. I am not with it today. Fixed.

 

[mt196]

I would be curious about how my updated version of the "Affordable Accuracy" measure. These were based on a widely available Dayton kit from Parts Express. I had an email exchange with Dennis a few months ago, where he informed me that he is no longer making speakers, and that he offered the crossover for the Dayton Affordable Accuracy version to Parts Express and that they turned him down. That is a real shame, since I prefer these to multiple budget speakers that got good reviews here.

So in practice he takes the pioneer, changes the tweeter, the woofer (is he using the Dayton audio 6.5" from part express?) and the crossover?

Am I missing something or maybe it would be better to also build a case by himself to save money instead of modding pioneer?

 

[MZKM]

So in practice he takes the pioneer, changes the tweeter, the woofer (is he using the Dayton audio 6.5" from part express?) and the crossover?

Am I missing something or maybe it would be better to also build a case by himself to save money instead of modding pioneer?

It is the same woofer, this one I believe.

 

[spacevector]

Question for Amir and Dennis: do you reckon one could get a good chunk of the way by applying EQ to the stock Pioneer speaker instead of making physical mods to the driver, crossover and cabinet?

 

[mt196]

It is the same woofer, this one I believe.

The same as the pioneer? It seems that in the new version of this product they are using a 6,5" woofer that looked exactly like the Dayton audio one

 

[edechamps]

I have added the Philharmonic Audio Affordable Accuracy Monitor to Loudspeaker Explorer where it can be compared to other speakers.

Good consistency within the listening window. The overall response is impressive compared to the speaker it's based on, or even in absolute terms, especially given the price:

 

[617]

Well behaved woofer makes this possible I would guess? I'd love to see the individual driver measurements just on axis.

Much respect to Dennis.

 

[DDF]

Sensitivity is decreased by 2dB (Claimed the same 85dB, for shame Dennis)

Looking at the crossover, Dennis added a 0.5 mH low pass inductor. Looking up the Jantzen used, it adds a dc resistance of 0.5 ohms right in series with the woofer. From @amirm measures of the originals, the original system impedance was ~ 5 ohms below the BDC frequency range and above port tuning frequencies. So, this added inductor will add ~ 0.8 dB loss to the ~ 200 to 400 Hz range. The rest of the difference in the bass will be due to

• Dennis added sonic barrier which will somewhat lessen port coupling efficiency, reducing sensitivity below 200Hz. This probably is the main contributor to getting rid of the 70Hz peak as well

• if not from the same production batch, raw drivers could easily have unit to unit variation of a dB, making up the rest

Dennis, any reason why you kept the 3kHz crossover point and didn't lower it? The directivity would have been better matched. Too much distortion, dispersion issues, etc??
Here is detailed info on the mod (slightly altered).

The vertical off axis dip in the response curve gives away the crossover frequency as ~ 2.7 kHz (eyeballing it from the graph):

Its also a fairly steep notch, also giving away a fairly steep high pass.

The crossover schematic confirms this, being 3rd order electrical (18 dB/octave asymptotic). The 2.2uF cap helps get rid of the tweeter impedance peak at resonance, keeping the crossover rolling off:

Checking out the hificompass test shows that the Vifa tweeter's distortion @ 4V takes off below ~ 2.5 kHz:

4V would be ~ 96 dB at one meter. From the data sheet:

(above a few kHz, the tweeter operates in half space on the baffle)

So, putting this all together, the third order crossover at 2.5kHz to 3 kHz is a very sensible choice to keep the tweeter distortion in check all the way to quite high playback levels.

I think Dennis made another really good choice elevating the on axis slightly from 800Hz to 3 kHz, to help compensate for the woofer's off axis roll in this range (as shown by the DI curve). I find this definitely helps make the spectral balance a bit more neutral in my designs. This is where allot of Dennis' voicing black magic comes in, because there are no hard and fast rules how much extra on axis response is needed to compensate for the roll off off-axis (and it can depend on room placement a bit), but IME and looking at the dispersion, I would expect this to be about perfect.

I also think its great that Dennis was able to keep cost down by not replacing any big inductors, just adding one small lower cost one. This choice would have reduced the amount of design freedom he had available, so it makes this result even more impressive.

Looks like a collection of great design choices, but no surprise there.

 

[aarons915]

Sure, the bass driver craps out all of a sudden when you play loud with low frequency content. I adjusted the volume so that it was high enough in my huge space while avoiding its limit. I was then greeted with some of the best mid to high frequency presentation I had heard. Female vocals were to die for. Anything with a high frequency transients was produced with a clarity and beauty that was uncanny. They stood out not be cause they were over emphasized but because they were so clean and for a lack of a better word, "hi-fi."

I was fully expecting you not to like this speaker because of the small woofer even after seeing the great measurements. I think this was a much more fair method of evaluating a speaker with a small woofer, playing loud enough without going over any obvious mechanical limits. I think it would be useful doing this for further reviews and possibly stating what SPL levels and distance you were listening at just for some kind of idea of SPL capability.

 

[MZKM]

Looking at the crossover, Dennis added a 0.5 mH low pass inductor. Looking up the Jantzen used, it adds a dc resistance of 0.5 ohms right in series with the woofer. From @amirm measures of the originals, the original system impedance was ~ 5 ohms below the BDC frequency range and above port tuning frequencies. So, this added inductor will add ~ 0.8 dB loss to the ~ 200 to 400 Hz range. The rest of the difference in the bass will be due to

• Dennis added sonic barrier which will somewhat lessen port coupling efficiency, reducing sensitivity below 200Hz. This probably is the main contributor to getting rid of the 70Hz peak as well

View attachment 65662

• if not from the same production batch, raw drivers could easily have unit to unit variation of a dB, making up the rest

The vertical off axis dip in the response curve gives away the crossover frequency as ~ 2.7 kHz (eyeballing it from the graph):
View attachment 65665

Its also a fairly steep notch, also giving away a fairly steep high pass.

The crossover schematic confirms this, being 3rd order electrical (18 dB/octave asymptotic). The 2.2uF cap helps get rid of the tweeter impedance peak at resonance, keeping the crossover rolling off:

View attachment 65666

Checking out the hificompass test shows that the Vifa tweeter's distortion @ 4V takes off below ~ 2.5 kHz:

View attachment 65663

4V would be ~ 96 dB sensitivity/2.83V at one meter. From the data sheet: View attachment 65664
(above 2 khz, the tweeter operates in half space on the baffle)

So, putting this all together, the third order crossover at 2.5kHz to 3 kHz is a very sensible choice to keep the tweeter distortion in check all the way to quite high playback levels.

I think Dennis made another really good choice elevating the on axis slightly from 800Hz to 3 kHz, to help compensate for the woofer's off axis roll in this range (as shown by the DI curve). I find this definitely helps make the spectral balance a bit more neutral in my designs. This is where allot of Dennis' voicing black magic comes in, because there are no hard and fast rules how much extra on axis response is needed to compensate for the roll off off-axis (and it can depend on room placement a bit), but IME and looking at the dispersion, I would expect this to be about perfect.
View attachment 65669

I also think its great that Denis was able to keep cost down by not replacing any big inductors, just adding one small lower cost one. This choice would have reduced the amount of design freedom he had available, so it makes this result even more impressive.

Looks like a collection of great design choices, but no surprise there.

The distortion is indeed rising <2500Hz, but it is still relatively low

At 5.6Vrms, so ~99dB, the second harmonic is still <1% @2kHz, not sure of the THD.

 

[Grandzoltar]

Are some of the Salk Sound speaker crossover designs from Dennis Murphy? Even though he is retired I assume they still follow his template for each speaker. If this is true I would love to see some Salk speakers on the test bench.

 

[AudioJester]

I am still learning here but have always wondered with these cheaper speakers - if the crossover is always such a compromise why not go active with something like a minidsp and some cheap class D amps? Would that not be a better way to solve crossover errors than with passive components and crossover redesign?
I get here that the tweeter replacement also made a huge difference.