• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Can we discuss the BMR Tower?

Colonel7

Addicted to Fun and Learning
Joined
Feb 22, 2020
Messages
616
Likes
876
Location
Maryland, USA
Don't see waterfalls like that often...looking forward to hearing these this weekend!

image
 

alexis

Member
Audio Company
Joined
Jun 3, 2020
Messages
97
Likes
159
I would love to see the BMR Tower measured by @amirm. The shipping carton method looks a lot like the Revel F328Be minus the aluminum case. Looks like an awesome speaker. I look forward to trying it.

View attachment 163032
Looks so familiar. I'd just say we BMR / BMR Tower's cabinet maker also make many other brands that cost much more than the BMR / Tower. The finish quality is similar although several samples I've seen has way fancier cabinet design than ours.
 

Ron Texas

Master Contributor
Joined
Jun 10, 2018
Messages
6,078
Likes
8,916
I would love to see the BMR Tower measured by @amirm. The shipping carton method looks a lot like the Revel F328Be minus the aluminum case. Looks like an awesome speaker. I look forward to trying it.

View attachment 163032
Logistics make testing towers difficult. Shipping is very expensive. The difficulty of lugging heavy towers through his house or mounting them on the klippel is something I can appreciate.
 

Dennis Murphy

Major Contributor
Technical Expert
Joined
Mar 17, 2020
Messages
1,071
Likes
4,535
Everything else is flat (as it should be in 2021 made loudspeaker) but 3dB isn't a small peak.

Port resonance usually causes dip on axis so that seems unlikely to me. I'd check that more thoroughly if i had the speakers on me.
The little blip is really more like 2 dB, and it doesn't show up on any of my measurements. I've attached my on-axis plot of one of the towers. I get pretty good resolution in the 600 Hz region. See below.

BMR Tower On Axis (2).png
 

Dennis Murphy

Major Contributor
Technical Expert
Joined
Mar 17, 2020
Messages
1,071
Likes
4,535
The little blip is really more like 2 dB, and it doesn't show up on any of my measurements. I've attached my on-axis plot of one of the towers. I get pretty good resolution in the 600 Hz region. See below.

View attachment 163035
And to keep things in perspective, compare the$3,700 BMR tower with the same type plot James made of the $16,000/pair Perlisten tower:

image_preview2


image_large2
 

amper42

Major Contributor
Joined
Dec 21, 2020
Messages
1,584
Likes
2,288
Logistics make testing towers difficult. Shipping is very expensive. The difficulty of lugging heavy towers through his house or mounting them on the klippel is something I can appreciate.

The BMR Tower weighs 72lbs. The Revel F328Be that @amirm tested weighs 112lb. The BMR Tower is a baby in comparison. I'm sure he could test it nicely in the garage. I doubt his wife would volunteer to help move it upstairs. :D

The hard part may be getting the Klippel Near-field Scanner (NFS) to accurately measure the bass response as the 8" ScanSpeak Revelator driver is a bit of a distance from the RAAL tweeter.
 

Zvu

Addicted to Fun and Learning
Joined
May 1, 2020
Messages
830
Likes
1,416
Location
Serbia
The little blip is really more like 2 dB, and it doesn't show up on any of my measurements. I've attached my on-axis plot of one of the towers. I get pretty good resolution in the 600 Hz region. See below.

View attachment 163035

To get a decent resolution below 1kHz you need at least 10ms gate time. Now i don't know what am i looking at in this graph but it doesn't look like anechoic and certainly not like high resolution measurement. Larson's measurements are much better in that regard.

Now look, i don't mean anything bad by writing what i did, but it is there. There is so much good stuff going on in this loudspeaker to be dismissive of one constructive critique that is aimed on making the preformance even better. I also don't want to make an auction about how high is that peak. It is observable in polar map measurements as well. I'd be curious what that resonance is if i was to put my signature on that speaker, doesn't mean you should be to.

Why didn't Larson post spinorama, as he did with BMR Philharmonitor ?
 
Last edited:

hardisj

Major Contributor
Reviewer
Joined
Jul 18, 2019
Messages
2,907
Likes
13,908
Location
North Alabama
The hard part may be getting the Klippel Near-field Scanner (NFS) to accurately measure the bass response as the 8" ScanSpeak Revelator driver is a bit of a distance from the RAAL tweeter.

Not a problem at all.
 

Ron Texas

Master Contributor
Joined
Jun 10, 2018
Messages
6,078
Likes
8,916
The BMR Tower weighs 72lbs. The Revel F328Be that @amirm tested weighs 112lb. The BMR Tower is a baby in comparison. I'm sure he could test it nicely in the garage. I doubt his wife would volunteer to help move it upstairs. :D

The hard part may be getting the Klippel Near-field Scanner (NFS) to accurately measure the bass response as the 8" ScanSpeak Revelator driver is a bit of a distance from the RAAL tweeter.
The F328Be came from a supplier to his business and did not have to be shipped back to a member. You should note his remarks about the difficulty of testing towers.
 

Dennis Murphy

Major Contributor
Technical Expert
Joined
Mar 17, 2020
Messages
1,071
Likes
4,535
Not a problem at all.
It was a coin flip on who to ask for a review. At the time, I thought the Audioholics measurements would include a full spin. I happen to be a fan of James'breadth of musical taste, and I thought from a subjective standpoint the tower might be a better fit given its design objectives.
 

alexis

Member
Audio Company
Joined
Jun 3, 2020
Messages
97
Likes
159
To get a decent resolution below 1kHz you need at least 10ms gate time. Now i don't know what am i looking at in this graph but it doesn't look like anechoic and certainly not like high resolution measurement. Larson's measurements are much better in that regard.
I can get great resolution at 1kHz w/ 5-6ms in my room using OmniMic. To get it down to 200Hz, I need to move a few things around (less reflective) and use longer gate time.
 

Zvu

Addicted to Fun and Learning
Joined
May 1, 2020
Messages
830
Likes
1,416
Location
Serbia
@alexis Every software applies more smoothing when doing gated measurements as you get closer to gate frequency/time. With gate of 5-6ms you get something like 1/6 octave smoothing below 1kHz. If there is need for high resolution measurements (and there is, at least when you are developing a loudspeaker) you need to get to at least 1/24 octave smoothing.
 
Last edited:

HammerSandwich

Major Contributor
Forum Donor
Joined
Nov 22, 2018
Messages
1,137
Likes
1,497
Agreed. With the port being on the front, you should have a dip if the port is the culprit. Rear ports result in a peak. Usually not from the port itself but from the port leaking internal resonance.
600Hz is a 57cm wavelength, so I'd think this would depend on relative distances between mic, driver(s), & port(s). Are you talking about merging nearfield measurements?
 

richard12511

Major Contributor
Forum Donor
Joined
Jan 23, 2020
Messages
4,335
Likes
6,700
Larson's review of the BMR Tower is up at Audioholics.

Nice work, @Dennis Murphy - the polars are simply outstanding.

Nice! Just about what I was expecting. Maybe the best value of any speaker at that price, wider dispersion than Revel towers, and extends much deeper than any Revel other than the Salon2(which it barely misses).

Looks like a Golf panther to me, and based on Amir's known preferences/testing:

1. Plays speakers full range, and loves deep bass
2. Likes wide horizontal dispersion, and tests in mono(where wide does even better)
3. Likes drivers that are spaced far apart vertically(for a taller vertical image), which these are
4. Likes neutral speakers, which these are

I'm fairly confident that Amir would love it. Only problem I could see him finding with it would be maybe dynamics(max output), but for normal volume 2.0 listening, I'd rather have the extra extension that these bring.
 

Dennis Murphy

Major Contributor
Technical Expert
Joined
Mar 17, 2020
Messages
1,071
Likes
4,535
@alexis Every software applies more smoothing when doing gated measurements as you get closer to gate frequency/time. With gate of 5-6ms you get something like 1/6 octave smoothing below 1kHz. If there is need for high resolution measurements (and there is at least when you are developing a loudspeaker) you need to get to at least 1/24 octave smoothing.
Praxis and Omnimic (both by the same designer) gradually lengthen the sampling window as you get below the 800 Hz point or so. By 200 Hz, the response is purely room. I'm not sure how this affects resolution at 600 Hz, although all those little ripples on my measurement suggest that no smoothing has been invoked. Anyhow, I don't want to get into an argument about this. Right now I'm in quasi-panic mode trying to get everything ready for the Capital Audio Fest. When it's over, I'll measure the bajeezus out of each tower and see whether I can figure out what, if any thing, is going on.
 

amper42

Major Contributor
Joined
Dec 21, 2020
Messages
1,584
Likes
2,288
Thank you for all your hard work @Dennis Murphy . Your efforts to lift speaker design to new levels is very much appreciated. Your attention to detail is extraordinary! My BMR monitors are amazing and I look forward to having a pair of black BMR Towers to enjoy by Christmas time. Have an enjoyable time at the Capital Audiofest.

capital.png
 

HammerSandwich

Major Contributor
Forum Donor
Joined
Nov 22, 2018
Messages
1,137
Likes
1,497
Right now I'm in quasi-panic mode trying to get everything ready for the Capital Audio Fest. When it's over, I'll measure the bajeezus out of each tower and see whether I can figure out what, if any thing, is going on.
For extra credit, ask any professional reviewers who stop by to ID which speaker is +2dB at 600Hz, at least after they hear a couple tracks unprompted. I'm sure the analysis will be enlightening about the real-world audibility.

Prediction: with pink noise & head movement, plausible. With music from 8+'? Good luck.
 

R Swerdlow

Member
Joined
Jun 9, 2020
Messages
74
Likes
114
To get a decent resolution below 1kHz you need at least 10ms gate time. Now i don't know what am i looking at in this graph but it doesn't look like anechoic and certainly not like high resolution measurement. Larson's measurements are much better in that regard.

Now look, i don't mean anything bad by writing what i did, but it is there. There is so much good stuff going on in this loudspeaker to be dismissive of one constructive critique that is aimed on making the preformance even better. I also don't want to make an auction about how high is that peak. It is observable in polar map measurements as well. I'd be curious what that resonance is if i was to put my signature on that speaker, doesn't mean you should be to.

Why didn't Larson post spinorama, as he did with BMR Philharmonitor ?
I do appreciate that your comment is indeed constructive. Please don't take my posts as an unreasonable defense.

James Larson said in his review:
The Philharmonic BMR Towers were measured in free-air at a height of 4 feet at a 2-meter distance from the microphone, with the microphone raised to a 7.5’ elevation that was level with and aimed at the tweeter center. The measurements were gated at 8-milliseconds. In this time window, some resolution is lost below 400 Hz and accuracy is completely lost below 200 Hz. Measurements have been smoothed at a 1/24 octave resolution.

On AH, he also was asked about the 600 Hz bump. He replied:
I did do near-field measurements of the drivers and port, and that hump does look to be an artifact of the port. It's not significant enough to be audible …
This does suggest that the various graphs showing the 600 Hz bump have a greater visual impact than it's sound does to at least one listener.

All in all, this review reveals what seems to be a wonderful speaker. With that out of the way, bring on those cheap shots from the peanut gallery ;) :rolleyes::
• That it can't be driven by 5 watt amp
• That the grills look like they were mounted wrong
• That it suffers from the lack of controlled dispersion
 
Top Bottom