Philharmonic BMR Monitor Semi-Objective Review - Road Show Stop 1

[Jdunk54nl]

Is the centre just a bookshelf or is there a a different center designed too? I'd chip in for $20 of the shipping

Just the tweeter rotated 90 degrees, which would be interesting to know the data for that horizontal orientation vs. vertical....
I will probably build a custom av rack that allows me to place it vertically, just not initially.

 

[BluesDaddy]

Just the tweeter rotated 90 degrees, which would be interesting to know the data for that horizontal orientation vs. vertical....
I will probably build a custom av rack that allows me to place it vertically, just not initially.

I believe Dennis has mentioned more than once that a vertical BMR has superior dispersion to a horizontal one with the RAAL rotated.

 

[Jdunk54nl]

I believe Dennis has mentioned more than once that a vertical BMR has superior dispersion to a horizontal one with the RAAL rotated.

Ya, it would be nice to know how much of a tradeoff it is. Building a custom tv stand wasn't fun the first time, building another is not something I really want to do but would if there was a substantial tradeoff.

I am sure the bmr and woofer interfere with the horizontal dispersion of the RAAL when layed horizontal that wouldn't impact the vertical (since these speakers would then be under/above the tweeter). But how much they interfere is the big question that I can't answer without the data. Then is that interference worth me building a new tv/av stand (note our tv is actually currently wall mounted but I would like to eventually go with a UST projector and 100"-120" ALR screen). All of my speaker wiring is also behind the current av stand so moving it to a corner wouldn't work for that and because subs are there.

 

[BluesDaddy]

Ya, it would be nice to know how much of a tradeoff it is. Building a custom tv stand wasn't fun the first time, building another is not something I really want to do but would if there was a substantial tradeoff.

I am sure the bmr and woofer interfere with the horizontal dispersion of the RAAL when layed horizontal that wouldn't impact the vertical (since these speakers would then be under/above the tweeter). But how much they interfere is the big question that I can't answer without the data. Then is that interference worth me building a new tv/av stand (note our tv is actually currently wall mounted but I would like to eventually go with a UST projector and 100"-120" ALR screen). All of my speaker wiring is also behind the current av stand so moving it to a corner wouldn't work for that and because subs are there.

I don't think the tradeoff is much and, in a blind listening, may not be noticeable at all. IIRC, there was a good deal of discussion three years ago or so on this in the thread at AVS Forums. I'm really digging deep in the faded memory banks...

 

[Dennis Murphy]

Ya, it would be nice to know how much of a tradeoff it is. Building a custom tv stand wasn't fun the first time, building another is not something I really want to do but would if there was a substantial tradeoff.

I am sure the bmr and woofer interfere with the horizontal dispersion of the RAAL when layed horizontal that wouldn't impact the vertical (since these speakers would then be under/above the tweeter). But how much they interfere is the big question that I can't answer without the data. Then is that interference worth me building a new tv/av stand (note our tv is actually currently wall mounted but I would like to eventually go with a UST projector and 100"-120" ALR screen). All of my speaker wiring is also behind the current av stand so moving it to a corner wouldn't work for that and because subs are there.

By placing the BMR on its side, you will run into nulls at the crossover points if you way off axis. So if you have a crowd over and some are sitting next to the potted plants by the windows, the center sound might lack a little presence. The effect wouldn't be as extreme as the off-axis nulls you get with an MTM, but a well designed WMTW will do better. I have a WMTW design for the BMR that you can have built by Jim Salk, but I don't think it's worth the extra cost unless you frequently have listeners sitting way off axis.

 

[Jdunk54nl]

By placing the BMR on its side, you will run into nulls at the crossover points if you way off axis. So if you have a crowd over and some are sitting next to the potted plants by the windows, the center sound might lack a little presence. The effect wouldn't be as extreme as the off-axis nulls you get with an MTM, but a well designed WMTW will do better. I have a WMTW design for the BMR that you can have built by Jim Salk, but I don't think it's worth the extra cost unless you frequently have listeners sitting way off axis.

Just out of curiosity, what does "way off axis" mean? 60 degrees? 75 degrees? Something else?

We will normally slide our couches around the chairs and make a horseshoe that has about a 60 degree arc for the majority of people. Also, in reality, I don't really care about them . Most of our friends we have over for movie nights use tv speakers still. My critical listening group doesn't really care either because we aren't critically listening at that time. We can all get over most poor sound unless it is just being distorted to garbage (Like the recent concert I went to ...I couldn't enjoy it)

 

[Dennis Murphy]

Just out of curiosity, what does "way off axis" mean? 60 degrees? 75 degrees? Something else?

We will normally slide our couches around the chairs and make a horseshoe that has about a 60 degree arc for the majority of people. Also, in reality, I don't really care about them . Most of our friends we have over for movie nights use tv speakers still. My critical listening group doesn't really care either because we aren't critically listening at that time. We can all get over most poor sound unless it is just being distorted to garbage (Like the recent concert I went to ...I couldn't enjoy it)

I guess 60 degrees is about where the effect might be pretty audible. But probably only in comparison with the on-axis sound. It should still be good enough for government work.

 

[birkbott]

I just got my monitors and (after dialing them in with Dirac) they sound absolutely superb.

 

[sweetmusic]

For all the BMR lovers on this thread: do you think there's any objective measurable data that could explain why the RAAL tweeters sound "magical" on some material?

This is a case where the spinorama data seems to favor domes, or concentric drivers. For example, Revel PerformaBe, or KEF.

Is it possible that the "magical" sound is directly related to the dispersion? Is it because of the reduced dispersion and room reflections that the upper frequencies come more into focus and that's what it means to say it's magical?

Or is there something else about the ribbon tweeter that might explain your preference? Could it be group delay or impulse response or dynamics or...?

Genuinely curious. I own two-way monitors with RAAL tweeters, Lyngdorf room correction and a sub, and I'm trying to understand what objectively might explain my own perception of them.

 

[Chromatischism]

For all the BMR lovers on this thread: do you think there's any objective measurable data that could explain why the RAAL tweeters sound "magical" on some material?

Yes. Look at polar plots to see how the speaker lights up the side walls. I don't believe it has to do with anything else like "speed", etc, no matter what some people say.

 

[sweetmusic]

Yes. Look at polar plots to see how the speaker lights up the side walls. I don't believe it has to do with anything else like "speed", etc, no matter what some people say.

Here's a comparison of the BMR to the KEF Reference 1 Meta:

That's certainly different and ought to be audible! Maybe it's the full explanation.

I see that the BMRs provide a similarly broad dispersion across the full frequency range. IIUC, that would have been a conscious choice, and they would have chosen the mid and woofer especially to match the RAAL. Similarly, the KEF mid and woofer match the concentric tweeter in their dispersion angle.

Do you happen to know if this horizontal dispersion pattern is common to all of the RAAL tweeters? Earlier in this thread, I see mention of different tweeter dimensions, and speculations as to how they might perform differently.

Also, anybody have thoughts on what the subjective experience of wide dispersion vs narrow dispersion is? Would one or the other be preferable based on room size and damping, or type of music (like an intimate ensemble with vocals vs a live recording of a big band), or how it's recorded or mixed? Or do you think it's more of a personal preference thing, and a panel of blind testers listening behind a scrim wouldn't agree on what sounds best in those various conditions?

 

[Chromatischism]

The BMR is probably not a good speaker to use for comparison due to its ultra-wide dispersion midrange driver. I would look at an Ascend speaker instead just to ensure any conclusions aren't tainted by that driver.

 

[Chromatischism]

Do you happen to know if this horizontal dispersion pattern is common to all of the RAAL tweeters? Earlier in this thread, I see mention of different tweeter dimensions, and speculations as to how they might perform differently.

Definitely. The radiation pattern is a result of the driver's shape. If you make a driver tall but skinny, it will have almost no vertical dispersion and a lot of horizontal. Equally, think about what we've seen from horizontal "center channel" speaker measurements. The longer the speaker gets, the more horizontal dispersion is narrowed and the wider it gets in the vertical plane.

I don't know if we fully understand the effects of vertical reflections compared to reflections from the sides. I would guess they matter, but probably less than the sides due to the way our hearing is optimized.

 

[sweetmusic]

The BMR is probably not a good speaker to use for comparison due to its ultra-wide dispersion midrange driver. I would look at an Ascend speaker instead just to ensure any conclusions aren't tainted by that driver.

Couldn't find a globe image for the Ascend, or images with all normalized or all not normalized. Maybe it's still useful to see:

Ascend (not normalized)

BMR:

KEF Reference 1 Meta:

 

[Dennis Murphy]

For all the BMR lovers on this thread: do you think there's any objective measurable data that could explain why the RAAL tweeters sound "magical" on some material?

This is a case where the spinorama data seems to favor domes, or concentric drivers. For example, Revel PerformaBe, or KEF.

Is it possible that the "magical" sound is directly related to the dispersion? Is it because of the reduced dispersion and room reflections that the upper frequencies come more into focus and that's what it means to say it's magical?

Or is there something else about the ribbon tweeter that might explain your preference? Could it be group delay or impulse response or dynamics or...?

Genuinely curious. I own two-way monitors with RAAL tweeters, Lyngdorf room correction and a sub, and I'm trying to understand what objectively might explain my own perception of them.

The RAAL certainly has a different sonic signature than the domes I've worked with. I'm not saying the RAAL is "magical," but it is different. Some would ascribe the difference to the extremely low mass of ribbon element, but that has been pretty much debunked on this forum. Part is due to the 64-10's extremely broad horizontal dispersion, but I've heard the same character on the 70-20, which has narrower dispersion. If you play some pink noise or white noise on a RAAL-equipped speaker, and compare that sound immediately with a dome-equipped speaker, you will hear much more energy in the sssssssssssssssssss region with the dome. The ribbon will sound like the sound of the dome has been stretched out. The difference isn't minor, and anyone will hear it if they step into my living room. Maybe the wave launch of the dome is more like a point source, and the ribbon more like a line source? That could be total BS--I'm just stretching for an explanation. For me, the ribbon characteristic translates into a more realistic reproduction of strings, cymbals, triangles, etc. But for studio recordings with no natural ambiance, particularly vocals, I can see where a lot of people would prefer the dome sound, feeling it is more focused.

 

[Chromatischism]

If you play some pink noise or white noise on a RAAL-equipped speaker, and compare that sound immediately with a dome-equipped speaker, you will hear much more energy in the sssssssssssssssssss region with the dome. The ribbon will sound like the sound of the dome has been stretched out.

That is a very interesting way to put it. I like explanations that I can relate to something visual to understand the concept.

So you would use the term focused and diffused. Technically, the sound could be more diffuse and have the same frequency response. It just means the energy per cm² is less (SPL). Does this still hold if the level is turned up?

Would you say it's like a flashlight with an adjustable beam spread?

 

[Dennis Murphy]

That is a very interesting way to put it. I like explanations that I can relate to something visual to understand the concept.

So you would use the term focused and diffused. Technically, the sound could be more diffuse and have the same frequency response. It just means the energy per cm² is less (SPL). Does this still hold if the level is turned up?

Would you say it's like a flashlight with an adjustable beam spread?

Well--the problem is I hear the same difference even when I compare small domes with broad dispersion to the RAAL. I think it's more than a question of dispersion.

 

[sweetmusic]

The RAAL tweeters do have a lot more distortion than a dome. I'm guessing that's not why people prefer them though.

Is the decay in the step response any different than a dome?

Here's Erin's review of the BMR and the KEF:

I admit I don't really know how to interpret these plots. In my limited understanding you want smooth lines without any jagged bumps. In Stereophile reviews, John Atkins always writes about "smooth handoff between the drivers". Is there anything else useful here?

 

[Dennis Murphy]

The RAAL tweeters do have a lot more distortion than a dome. I'm guessing that's not why people prefer them though.

Is the decay in the step response any different than a dome?

Here's Erin's review of the BMR and the KEF:

I admit I don't really know how to interpret these plots. In my limited understanding you want smooth lines without any jagged bumps. In Stereophile reviews, John Atkins always writes about "smooth handoff between the drivers". Is there anything else useful here?

I'm not sure how to interpret those either. The hand-off is fine for both speakers--the differences are further along in the decay.

 

[pjug]

I'm not sure how to interpret those either. The hand-off is fine for both speakers--the differences are further along in the decay.

Erin's plots above are the old BMR. Doesn't the new one have a lower order low end crossover, so much different step response? Has it been measured?