Philharmonic Audio BMR Speaker Discussion

[Alexanderc]

You see this a lot on rear ported speakers in the soundstage measurements. Below 80hz or so it seems best to take it with a grain of salt.

 

[Dennis Murphy]

@Dennis Murphy Could you, perhaps share also off-axis -15 -30 -45 measurements of the BMR that you are using? I spent a few years building active speakers with 4.5 inch BMRs as a fullrange, crossed over to small subbass section, and i must say, that there is indeed something special about their sound, also thanks to the DML/BMR principle they can take unbelievable beating given their size, but after a lot of extatic overreactions, and long time experimentations i have found out, that their biggest advantage is also their biggest weakness- you almost cannot equalise BMR driver to have reasonable radiation pattern- their response is changing wildly with each small turn from the axis. That, and also the BMR specific distortion, which is unrelated to the current SPL makes them finally disqualified from my future projects, and that is in my opinion the reason why these interesting drivers would never be widely used in high end audio.

Swerdlow has already illustrated the off-axis performance of the BMR, and you can see complete 3rd party Sinorama measurements here:
https://www.audioholics.com/bookshelf-speaker-reviews/bmr-philharmonitor-1/conclusion
I can only conclude that you were using a different driver (I'm not familiar with any BMR larger than the 3" I used), or somehow measuring differently. I also haven't encountered any distortion issues. The NRC didn't run into any even at 90 dB at 2 meters. The RAAL ribbon does start to huff and puff at the bottom of its range when driven that hard, but not the midrange.

 

[Ilkless]

https://www.avsforum.com/forum/89-s...nic-audio-dennis-murphy-339.html#post59906244

Dennis had to give up on the Purifi because it simply wasn't suited for the BMR form factor:

I've given the Purifi woof every opportunity to prove itself in the BMR, including running it with two of the Purifi passive radiators, and I finally gave up. It's a very specialized animal. It performs about as well as the Scan 8545 in a smaller cabinet, which makes it a prime candidate for a premium 2-way in a cabinet of .5 cu ft or less. But even in that application the port has to be too long to fit without bending it and introducing even more port noise. The passive radiators solve that problem, but in a larger cabinet the bass response falls off below 100 Hz and the midbass is thin. Given how much more expensive the woofer + PR's are compared with the Scan, it doesn't make sense to reduce the volume of the BMR cabinet to achieve essentially the same results. Also, I have been extremely impressed with the performance of the SB Acoustics ceramic woofers, and have decided to incorporate the 5", 6", and probably 8" in a series of speakers manufactured in China and sold here starting in the Fall. The first will be a mini monitor with an excellent AMT tweet for nearfield listening and HT surround. The second will be the BMR with the 6" ceramic, and the third, not yet designed or proven, could be a tower with the 8" ceramic, two BMR mids, and the RAAL tweet. That way, each speaker will have specialized applications appropriate for their asking price, and not just a marginal improvement at greatly added cost. The new BMR shouldn't be regarded as an improvement over the Scan version currently available as a kit. It will have somewhat higher sensitivity and the bass extension will be the same at normal output levels. But the Scan still has more power handling for rockers. The reason for switching to the 6" ceramic is to reduce cost enough to keep the regular BMR relatively affordable. Given the trade war, however, the price will be enough higher than the kit to make that an attracitive option for DIY'ers. The Chinese have become more flexible of late when it comes to cabinet quality and variety, and the new BMR's will have a very high-end veneer finish and eventually a wide range of finish choices.

https://www.facebook.com/parodielinaudio

I managed to find Dennis' Taiwanese partner after some digging with my rusty Mandarin. As far as I can tell it is becoming a cult classic over there.

I'm not sure if the curves have been shared, but here're the 0-20-45 degree off-axis curves of the upcoming SB ceramic variant - cheaper and as good unless you need Scanspeak's superior power handling.

https://www.facebook.com/parodielinaudio/posts/3067887966592786

 

[R Swerdlow]

The best and easiest way to check for bass tuning is with an impedance sweep. Do you have the ability to measure impedance? If so, the two impedance peaks forming the saddle should be absolutely symmetrical, and the saddle should be centered on about 33 Hz.

For those who can measure impedance of their BMR kits, here are two impedance vs. frequency graphs. For bass performance, the important feature to look for is the impedance saddle at ~33 Hz between the two impedance peaks.

Done by James Larson of Audioholics. Dark green is impedance magnitude vs. frequency (read ohms on the left vertical axis). The other curve in light green is impedance phase angle (read degrees on the right vertical axis).

And here are the impedance phase (upper panel) and impedance magnitude (lower panel) measured by the NRC.

Note that the NRC graphs don't show frequencies below 20 Hz. In contrast, the AH graphs shows frequencies down to 10 Hz. Otherwise, they look similar.

 

[Adam Bernau]

Swerdlow has already illustrated the off-axis performance of the BMR, and you can see complete 3rd party Sinorama measurements here:
https://www.audioholics.com/bookshelf-speaker-reviews/bmr-philharmonitor-1/conclusion
I can only conclude that you were using a different driver (I'm not familiar with any BMR larger than the 3" I used), or somehow measuring differently. I also haven't encountered any distortion issues. The NRC didn't run into any even at 90 dB at 2 meters. The RAAL ribbon does start to huff and puff at the bottom of its range when driven that hard, but not the midrange.

Yes, i was using BMR85DDXE N4R from Cotswold Sounds, from UK. Perhaps you are also familiar with their products?
Maybe the smaller driver that you are using behaves better, i am just waiting till someone in Europe will sell his used Philharmonitors, so i can test them myself

 

[Dennis Murphy]

Yes, i was using BMR85DDXE N4R from Cotswold Sounds, from UK. Perhaps you are also familiar with their products?
MAybe the smaller driver that you are using behaves better, i am just waiting till someone in Europe will sell his used Philharmonitors, so i can test them myself

I'll check them out. It's possible the bending principle doesn't work as well on larger diaphragms.

 

[MZKM]

I see Salk is selling a used pair for $2K + shipping, but it‘s one Dennis made and in basic finish, which was like $1400 + shipping. Is Salk just trying to make a quick profit?

For those of use that want the minimal amount of DIY, it looks like it costs ~$1700-$1800 + shipping for the drivers + assembled crossovers & assembled cabinets, so all you need to do is install (plus finishing if you want).

 

[bigredrobotninja]

Is Salk just trying to make a quick profit?

I think it's more that Dennis was making basically zero profit. His margins were famously thin.

 

[MZKM]

I think it's more that Dennis was making basically zero profit. His margins were famously thin.

Now that I think about it, it probably is probably used as a credit to upgrade and they gave the owner credit based on the current listing (even if the cabinet is not as good as Salk’s). So, they are helping out that customer by giving them a larger credit and thus likely purchasing a more expensive speaker from Salk. Still, paying more for a used model than what it used to cost new ain’t great.

 

[bigredrobotninja]

Oh I see what yiu

Now that I think about it, it probably is probably used as a credit to upgrade and they gave the owner credit based on the current listing (even if the cabinet is not as good as Salk’s). So, they are helping out that customer by giving them a larger credit and thus likely purchasing a more expensive speaker from Salk. Still, paying more for a used model than what it used to cost new ain’t great.

Oh I see what you mean, I didn't realize it was an actual Philharmonic model, not a Salk-built one. Yeah, that's kind of lame.

But then, you can't buy the Philharmonic ones new anymore, and if $2k is what the market bears...

 

[ribosradagast]

I have mine properly set up in my listening room now and I can honestly say: lol these things have a ton of bass! There's a huge standing wave rebounding off the wall behind my listening position that must be driving my neighbors crazy. Measurements-wise, they're going to need at least -6 DB of attenuation around 40 hz. Well played, scan speak, well played

 

[hardisj]

Can anyone tell me (because finding this specifically via google is turning out to be a chore):
What is the designed listening axis (vertical and horizontal) of this speaker?
I assume 0° horizontal and "tweeter" level veritically. But I would like to verify this for sure.

TIA

 

[bigjacko]

Can anyone tell me (because finding this specifically via google is turning out to be a chore):
What is the designed listening axis (vertical and horizontal) of this speaker?
I assume 0° horizontal and "tweeter" level veritically. But I would like to verify this for sure.

TIA

From measurements they are pretty flat from 0 to at like 45 degree, I guess toe in or not toe in are both okay? What do most people do wjen their speaker got wide directivity?

 

[Dennis Murphy]

From measurements they are pretty flat from 0 to at like 45 degree, I guess toe in or not toe in are both okay? What do most people do wjen their speaker got wide directivity?

I listen to my BMR's with no toe-in. If you look at the measurements Swerdlow posted, you'll see that there's a little dip at 3 kHz that goes away fairly quickly off axis. So the smoothest early arrival response will actually be off axis. Does it really make any doo da difference? Probably not, but at least you can be confident that you're not missing anything if you or your SO wants the speakers pointed straight ahead for aesthetic reasons.

 

[muad]

From measurements they are pretty flat from 0 to at like 45 degree, I guess toe in or not toe in are both okay? What do most people do wjen their speaker got wide directivity?

Can anyone tell me (because finding this specifically via google is turning out to be a chore):
What is the designed listening axis (vertical and horizontal) of this speaker?
I assume 0° horizontal and "tweeter" level veritically. But I would like to verify this for sure.

TIA

Yah it's zero degrees vertically. There was also no need to toe them in. When I had them, they had the most stable image no matter where I was. Even far off axis in the kitchen, they had a phantom center. I think I remember reading somewhere.in the AVS forum, Dennis recommending them to be used with no toe in? But that was a long time ago, so take it with a grain of salt.

 

[R Swerdlow]

Can anyone tell me (because finding this specifically via google is turning out to be a chore):
What is the designed listening axis (vertical and horizontal) of this speaker?
I assume 0° horizontal and "tweeter" level veritically. But I would like to verify this for sure.

I listened, two years ago, to the BMR speakers that made the BMR Road Trip. From one photo, it looks like they were arranged with no toe in. Dennis drove them to my nearby house and was present as we listened. So the speakers probably had no toe-in. I don't recall fussing about their arrangement.

But I do recall how wide their sweet spot was when I listened about 9-10 feet away – full sofa width plus some extra. I did make an effort to walk around the room as I listened, on- and off-axis. In the midrange and higher frequencies, the BMRs were highly forgiving no matter where I was.

 

[hardisj]

Thanks for the info, guys.

I am asking because I plan to measure these speakers and, while I assume on-axis horizontally and vertically aligned with the tweeter is the ideal reference plane, I want to make sure what the reference axes are before I go off half-cocked. Looks like my assumption is correct.

I've already begun my listening evaluation (something I always do before measuring or looking at measurements so I don't bias my opinion) and I started with the above orientation. I also moved them to forward-firing just to see how the angle effects the result.

 

[bigjacko]

Thanks for the info, guys.

I am asking because I plan to measure these speakers and, while I assume on-axis horizontally and vertically aligned with the tweeter is the ideal reference plane, I want to make sure what the reference axes are before I go off half-cocked. Looks like my assumption is correct.

I've already begun my listening evaluation (something I always do before measuring or looking at measurements so I don't bias my opinion) and I started with the above orientation. I also moved them to forward-firing just to see how the angle effects the result.

Nice, I am really looking into the individual driver performance, specially ribbon tweeter because there is no measurement of it.

 

[Poseidons Voice]

What an awesome review!

https://www.erinsaudiocorner.com/loudspeakers/philharmonic_bmr/

Best,
Anand.

 

[hardisj]

What an awesome review!

https://www.erinsaudiocorner.com/loudspeakers/philharmonic_bmr/

Best,
Anand.

DOH! I can't believe I forgot to link that here. Thanks for doing that!

Also, here's the discussion for those who haven't seen it:
https://www.audiosciencereview.com/forum/index.php?threads/philharmonic-bmr-speaker-review.14781/