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Can we discuss the BMR Tower?

buz

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Very impressive but like Revel probably not really available to Europeans, am I right?
 

Zvu

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I really should bite the bullet and find an unused basketball court, or buy a Klippel.

Basketball court is much cheaper option - the only option for me actually :)

Klippel can earn you some money if there are enough loudspeaker manufacturers on your continent so you could provide measurement service in loudspeaker development and high resolution measurements for datasheets.
 

Kachda

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Basketball court is much cheaper option - the only option for me actually :)

Klippel can earn you some money if there are enough loudspeaker manufacturers on your continent so you could provide measurement service in loudspeaker development and high resolution measurements for datasheets.
Fantastic showing. I really liked the Bmr monitor as part of the roadshow. When I have my own house where I can place towers, I’m buying these
 

Colonel7

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Cross-posting my BMR impressions from Capital Audiofest today. Let me say that these made me giddy on the O-zone track. There were a # of guys in the room who had to pick up their jaws off the floor. When they heard $3700 they just couldn't believe it, and that was before they realized it is per pair and not each. My poor phone camera pic doesn't do it justice but the finish on these are really nice and much better in person. Thinking Dennis will be making a lot of sales from the show.
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Dennis Murphy's BMR Towers in Room 306 are fantastic and were by far my favorites. There is no sweet spot, or more accurately, it's everywhere. Imaging, soundstage, and depth are great. He played some Leonard Bernstein and some Pink Floyd, as well as some female vocals that showed off the BMR mids and the RAAL. The Revelator in combination with the T-line are something else. Dennis has a track of O-zone percussion (it was like a 3-4 minute version of jazz variants I think) that really shows off the Scan Speak; just full and incredibly clear. Not as fun but he also played an organ version of God Save the Queen. I don't have the budget right now but I seriously thought of just ordering them and figuring the $3700 financials out later. Run, don't walk to get your BMR Towers. I really liked the BMR monitor but the Tower is just another level. Also heard Dennis' new version of the Affordable Accuracy with the Dayton classic 6.5" and the Dayton Silkie that is outstanding for what it is. the Philarmonic Audio room was nice and cool using that Ncore...
1636137940792.jpeg
 

sweetchaos

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Watched the video review.
I wish Audioholics would post the full spinorama though...

Is it fair to say, if you want wide-directivity tower speakers, but can't afford Revels, then get the BMR tower?
Any other options at <US$3700/pair for wide-directivity towers, or is just BMR tower?
 

Shazb0t

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Watched the video review.
I wish Audioholics would post the full spinorama though...

Is it fair to say, if you want wide-directivity tower speakers, but can't afford Revels, then get the BMR tower?
Any other options at <US$3700/pair for wide-directivity towers, or is just BMR tower?
For around that price, outside the Revels, I would also cross shop the Ascend Acoustics Sierra Towers w/ RAAL tweeter upgrade:

Measurements PDF

ASR Ascend Acoustics Horizon w/ RAAL review (same driver assortment, crossover points, and cabinet volume as the the above Towers)


If going for something non Revel comparable to the BMR bookshelves, then another option is the Ascend Sierra-2EX:

Klippel NFS Spinoroma:
Klippel NFS EIR
Klippel Horizontal Polar
Klippel NFS Early Reflections
Klippel NFS Magnitude of transfer function H(f)
 
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Jdunk54nl

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Here is the Asr measurements of the sierra 2 with raal
Personally there is no chance I’d buy this 2 way compared to the bmr 3 way, but the Asr data looks decent too.
 

jhaider

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Cross-posting my BMR impressions from Capital Audiofest today.

Curious - did you listen to them standing as well as sitting? If so from about how far away. It looks like a particularly good wide-horizontal directivity design. However, the long tweeter does fall off pretty quickly vertically. That makes any speaker with this kind of tweeter sound dull when going from seated to standing. I realize sound quality while well above the tweeter axis is simply not a priority for many. It does matter to some.

I’m curious how much the MTM configuration pulls the vertical directivity fall of lower. Subjectively I could see that cutting either way. Either they could sound more balanced in a sit-stand test or they could sound even duller.
 

Colonel7

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Curious - did you listen to them standing as well as sitting? If so from about how far away. It looks like a particularly good wide-horizontal directivity design. However, the long tweeter does fall off pretty quickly vertically. That makes any speaker with this kind of tweeter sound dull when going from seated to standing. I realize sound quality while well above the tweeter axis is simply not a priority for many. It does matter to some.

I’m curious how much the MTM configuration pulls the vertical directivity fall of lower. Subjectively I could see that cutting either way. Either they could sound more balanced in a sit-stand test or they could sound even duller.
I did. I moved around the room left to right and front to back, standing and sitting. I didn't notice any issues at all which really surprised me. I spent quite a bit of time standing almost against the back wall, I would say ~13 ft. That would be my listening distance in my family room. Keep in mind I'm only 5'7 so someone who is very tall might notice something I wouldn't. I even spent some time in the front row, sitting on the edge of the seat and leaning forward low; still sounded great. The towers were probably 7-8 feet apart, but I might be off on that one.

For some perspective the hotel room they're in is probably a king on the smaller side when set up for an overnight guest.

Edit: for a comparison, the Perlistens sounded much better to me sitting, and going off-axis horizontally was quick to notice the drop-off. They chose to toe those in 15 degrees of so where Dennis did not for the BMRs. The Perlistens are in a very large room though
 
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ctrl

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A considerable discrepancy was not addressed in the review (maybe I missed the part).
The manufacturer's and the reviewer's stated behavior of the speaker in the low bass range do not match at all.
Someone has made a serious mistake (sounds a bit melodramatic, no the end of the world is not triggered by this).

The f3 of 28Hz in the manufacturer's specification based on the manufacturer's measurement on the one hand.
The manufacturer measurement is based on near-field measurements of the driver and TL port. With dual channel measurements to correctly capture any non-minimum phase behavior of the TL port, not much can actually go wrong when calculating the overall frequency response from the two individual measurements if the basic rules are followed.
1636315447185.png

On the other hand, the Audioholic ground plane measurement. Nothing can actually go wrong with that either, if the basic rules are followed.
If you combine ground plane measurement and gated measurement and then generously assume that the average sound pressure level is 83.5dB (this is only the relative sound pressure level for the calculation, not the real sensitivity), you still only get an f3 of 53Hz. Only f6 is at 28Hz.
1636315599092.png 1636316243513.png

The point is not to evaluate the low frequency capabilities of the speaker, but that nearly an octave difference in measured f3 is so extremely different that guessing is likely to produce a better result.
This should be checked (of course also if my determined results are correct).

UPDATE: To make the difference clearer, here is a direct comparison of the two measurements (has the manufacturer perhaps forgotten the baffle step correction?):
1636319643771.png
 
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Dennis Murphy

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A considerable discrepancy was not addressed in the review (maybe I missed the part).
The manufacturer's and the reviewer's stated behavior of the speaker in the low bass range do not match at all.
Someone has made a serious mistake (sounds a bit melodramatic, no the end of the world is not triggered by this).

The f3 of 28Hz in the manufacturer's specification based on the manufacturer's measurement on the one hand.
The manufacturer measurement is based on near-field measurements of the driver and TL port. With dual channel measurements to correctly capture any non-minimum phase behavior of the TL port, not much can actually go wrong when calculating the overall frequency response from the two individual measurements if the basic rules are followed.
View attachment 163914

On the other hand, the Audioholic ground plane measurement. Nothing can actually go wrong with that either, if the basic rules are followed.
If you combine ground plane measurement and gated measurement and then generously assume that the average sound pressure level is 83.5dB (this is only the relative sound pressure level for the calculation, not the real sensitivity), you still only get an f3 of 53Hz. Only f6 is at 28Hz.
View attachment 163915 View attachment 163918

The point is not to evaluate the low frequency capabilities of the speaker, but that nearly an octave difference in measured f3 is so extremely different that guessing is likely to produce a better result.
This should be checked (of course also if my determined results are correct).

UPDATE: To make the difference clearer, here is a direct comparison of the two measurements (has the manufacturer perhaps forgotten the baffle step correction?):
View attachment 163931
It's late and I've spent 3 straight days in a hotel room demoing speakers and lugging everything back home, but I'm not really following this. James' ground plane measurements almost always show a declining response setting in relatively early. His results for the BMR tower are about the best I've seen. Compare these with the results for the giant Perlisten S7t tower (shown below). The factory spec for the speaker is a -10 dB point of 22 Hz. My nearfield measurements of the woofer and port combined response for the BMR tower were made without the crossover in place, since the baffle step compensation in the crossover filter will make it look like there's a peak in the midbass and a roll[-off in the lower midrange response. With room gain, the BMR tower is flat to 25 Hz, with useful output at 20 - 22 Hz.


image_large2
 
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blestin

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I am quite confused by the question, I read the wall of text and could not figure out the main point you were trying to make. Are you saying there is an issue with the audioholic measurements or the F3 of speaker itself?
 

fluid

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I am quite confused by the question, I read the wall of text and could not figure out the main point you were trying to make. Are you saying there is an issue with the audioholic measurements or the F3 of speaker itself?
What ctrl was pointing out is that the Audioholics measurement shows a higher F3 than that quoted by the manufacturer.

The manufactures graph and the Audioholics graph were not measured in the same way.

The Audioholics graph is the speaker measured with the crossover and baffle step compensation in place and shows a slower rolloff resulting in a higher calculated F3.

The manufacturers graph is a nearfield measurement without baffle diffraction compensation applied.

Dennis's point is that when measured in room with average room gain the F3 will drop back down to a similar level as the nearfield measurement.

So the comparison is between an apple, an orange and a pear :)
 

Dennis Murphy

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I am quite confused by the question, I read the wall of text and could not figure out the main point you were trying to make. Are you saying there is an issue with the audioholic measurements or the F3 of speaker itself?
Yes--it is a common result for the Audioholics ground plane measurements to show an earlier roll-off than is specified by the manufacturer. I'm not sure why this is, but it is a fact. And I think the discrepancy is wider than can be explained by differences in the measuring technique.
 
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blestin

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Thanks for clearing that up, I can subjectively attest to these towers having a very low extension. How low I can’t say, but I have 2 F12 rythmik subs and when I disable them and put the towers into full range it doesn't sound sound like I am missing the subs. Although it is noticeable at louder volumes while watching movies. I haven’t heard any other towers that can extend this low yet.
 

hardisj

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Yes--it is a common result for the Audioholics ground plane measurements to show an earlier roll-off than is specified by the manufacturer.

Interesting. I’ve not noticed this but I haven’t looked for it, either. I just take the GP results as they are and trust those more than I do any manufacturer’s spec because it’s pretty damn hard to screw up a GP measurement (and I’m NOT saying James did). Did you bring this to James’ attention?
 

tktran303

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The ground plane shows the true outdoor measurements in the bass not affected by reflections; and thus excellent estimate of true anechoic bass response. Difficulty can still exist when the radiators are on different planes of the cabinet; causing differing distances to the measurement mic.

A near field combined measurement (cone, passive radiator, port etc) not only eliminate room reflections but it also eliminates baffle diffraction, so the baffle step at lower frequencies is not shown in the data.

To show what a anechoic response would likely be; baffle diffraction must be modelled using a simulator; then it’s effects would need to be incorporated into the near field data, to show the typical response in the free field. This is not perfect either because most modellers only do 2D; and don’t typically account for the depth of the cabinet.

Dennis has shown the near field response, sans the diffraction losses. And stated the typical in-room response. Many manufacturers do this.

Nothing wrong with this…

Another method is to show a smoothed
in-room response from 20Hz up to the Schroeder frequency, blended with gated response from the Schroeder frequency up to 20Khz on the design axis at the design distance. Eg. 1m, 2m, 2.5m.

Until we get everyone agreeing to use one standard, disreprancies are going to exist.
But this is an academic topic for loudspeaker designers like ctrl and Dennis.

What really matters is these speaker go low. And cover the full spectrum for music.

Because in room it already goes down to 20Hz
So you only need a subwoofer for more SPL between 20-120Hz, but NOT for more extension,

So whether you need a subwoofer depends on how loud you like to listen…
 
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