balanced mode radiator (BMR) speakers

[scherbakov_al]

How interesting. You can try to simulate the driver yourself thanks to these suggested models. What an interesting time we live in!

Multiphysics Helped Design the Gold Standard for VR Audio

To develop a VR headset with immersive audio, Valve Corporation teamed up with Tectonic Audio Labs. See how they used multiphysics to achieve their goal.

www.comsol.ru

 

[extrasuper]

Advert from RS popped up elsewhere, and it turns out they are quite inexpensive: https://uk.rs-online.com/web/p/spea..._aQAxCixbBAvsW6Poy-pazCZ8itXlPxDKY804tAfD_BwE

 

[thewas]

Many good loudspeakers use Tektonic BMR chassis (especially https://www.tectonicaudiolabs.com/product/tebm46c20n-4b/?id=product-786 ), exemplary

Philharmonic BMR Speaker Review

Mostly copy/pasted from my review on my website. I took some out so if you want to see the full review go here: https://www.erinsaudiocorner.com/loudspeakers/philharmonic_bmr/ Philharmonic BMR Bookshelf Speaker Review Intro Dennis Murphy designed the Philharmonic BMR some years back and...

www.audiosciencereview.com

Philharmonic BMR Tower Speaker Review: Strike Gold Twice?

Philharmonic Audio BMR tower is a 3-way wide dispersion speaker that scales up the performance and bass output from of their fabulous Philharmonitor previously reviewed. Read on to see if how it’s done.

www.audioholics.com

Q Acoustics Introduces Q Active Loudspeaker Series Using Tectonic Balanced Mode Radiator Drivers

British audio brand Q Acoustics announced the Q Active 200 bookshelf speakers, its first active design, soon to be complemented with the Q Active 400 tower speakers. The Q Active series are the result of the company’s 14-year heritage and expertise in speaker design, in an effort to offer the...

audioxpress.com

 

[617]

The BMR's dispersion really does break a lot of rules for direct radiators. Probably the most innovative driver technology in years. Seems only to be applicable in small form factors however, and low efficiency.

 

[thewas]

And interestingly this technology is already more than 20 years old, but the company which initially made them didn't get popular back then.

https://loudmagnet.com/html/pdf/NXT%20Technology.pdf

NXT's flat speakers - making the right sound?

(CITYWIRE WEEKEND) NXT’s share price soared fivefold to a peak of nearly £25 earlier this year as excitement grew about its flat speaker technology, but there still aren’t many flat speakers in the shops, so Ed Bowsher decided to visit the company's chairman last week to examine the substance...

citywire.co.uk

Distributed mode loudspeaker - Wikipedia

en.wikipedia.org

 

[extrasuper]

I hadn't heard of BMR speakers before now, but have researched fairly extensively (and done some limited experiments) with DML tech. I actually have a couple little battery powered plug speakers (that did double duty as a CD case) that used NXT drivers from back in the day, called the TDK OutLoud. I did wonder (upon seeing this thread) if it was a similar tech - and seeing from the ad from RS that they were made by Tectonic, who also make DML drivers.

A couple of things that strike me though - low efficiency, only working at small form factor and being round in shape seem to run counter to what I recall being characteristics of DML panels.

 

[bigjacko]

BMR claimed to have wider dispersion then normal drivers, but after reading a lot of graphs I can't see how it has wider dispersion. Do you guys really found it to has wider dispersion or not? Other then that I think those drivers are alright, not a bad buy, peerless makes some good drivers around those sizes too, possibly cheaper and better performing.

 

[Shazb0t]

BMR claimed to have wider dispersion then normal drivers, but after reading a lot of graphs I can't see how it has wider dispersion. Do you guys really found it to has wider dispersion or not? Other then that I think those drivers are alright, not a bad buy, peerless makes some good drivers around those sizes too, possibly cheaper and better performing.

They have wider dispersion because they are physically smaller than more commonly used midrange drivers.

 

[617]

They have wider dispersion because they are physically smaller than more commonly used midrange drivers.

No, there is another mechanism at play. The balanced mode radiator essentially splits into smaller moving areas as frequency increases. Other drivers do this and we call it 'cone breakup' but with the BMR there are strategically placed masses that cause the cone to break up in a controlled fashion. So whereas most drivers are pistonic and then turn somewhat chaotic with increasing frequency, the BMR is still somewhat controlled when it is not behaving pistonically. In the frequency range where it is non-pistonic, it can essentially be considered a series of smaller radiating surfaces, and as we know, smaller radiators have wider dispersion. That's why it has the off-axis dispersion similar to a 19mm dome tweeter in a 2" midrange driver. It's a unique and remarkable achievement.

 

[Shazb0t]

No, there is another mechanism at play. The balanced mode radiator essentially splits into smaller moving areas as frequency increases. Other drivers do this and we call it 'cone breakup' but with the BMR there are strategically placed masses that cause the cone to break up in a controlled fashion. So whereas most drivers are pistonic and then turn somewhat chaotic with increasing frequency, the BMR is still somewhat controlled when it is not behaving pistonically. In the frequency range where it is non-pistonic, it can essentially be considered a series of smaller radiating surfaces, and as we know, smaller radiators have wider dispersion. That's why it has the off-axis dispersion similar to a 19mm dome tweeter in a 2" midrange driver. It's a unique and remarkable achievement.

And also, they're small..

 

[bigjacko]

The high frequency is wide, but the mid frequency is not as wide. I would hope they optimise the mid frequency more, but their market is not hifi....

 

[Head_Unit]

I periodically think about making a floor-to-ceiling line array out of these things.

NXT...yeah they never got the traction they were promising. The revolution is coming!...until it doesn't. Your whole car dashboard is going to be a speaker! Your TV and phone's screens will be the speaker! None of all that stuff happened at any scale AFAIK. Too bad. The part I always questioned was "what about the transient/impulse response" and I don't recall ever seeing that measured. Not even a big home panel. To make a wild guess, I'd surmise that when the panel gets big, it becomes too much chaotic surface to calculate (NXT's technology was not the flat speaker, that had been done before including by me. Their technology was actually a method of number crunching to predict the response of a transducer and thus be able to flatten its response).

 

[Head_Unit]

BMR claimed to have wider dispersion then normal drivers, but after reading a lot of graphs I can't see how it has wider dispersion. Do you guys really found it to has wider dispersion or not?

Here https://www.erinsaudiocorner.com/loudspeakers/philharmonic_bmr/ it really doesn't seem like it. Then again, wonderful as it may sound, I find the Philharmonic BMR to be an odd duck-if the BMR is so great why the heck is there a tweeter? I remember hearing the Cambridge speaker with a BMR and it seemed fine without.

Hey, is anyone besides Tectonic even MAKING BMR-type drivers? Is there anything that isn't like 82 dB sensitivity?

 

[bigjacko]

Here https://www.erinsaudiocorner.com/loudspeakers/philharmonic_bmr/ it really doesn't seem like it. Then again, wonderful as it may sound, I find the Philharmonic BMR to be an odd duck-if the BMR is so great why the heck is there a tweeter? I remember hearing the Cambridge speaker with a BMR and it seemed fine without.

Hey, is anyone besides Tectonic even MAKING BMR-type drivers? Is there anything that isn't like 82 dB sensitivity?

The ribbon tweeter just has too wide horizontal dispersion that BMR can never has. Dennis likes the BMR only as a mid range and likes ribbon tweeter because of the side dispersion.

 

[hex168]

You can compare off-axis frequency responses here:

Tectonic TEBM46C20N-4B | HiFiCompass

The THD measurements at distance of 315 mm and voltage level 2.83 Volt were carried out with High Pass Filter "on" (2nd order Buttreworth type, 100 Hz cutoff, HPF2-100) The THD measurements at distance of 315 mm and voltage levels from 4 Volt to 5.6 Volt were carried out with High Pass Filter...

hificompass.com

A 1" tweeter is much neater up high:

Peerless BC25TG15-04 | HiFiCompass

hificompass.com

But the Tectonic is much better at 10K than a 2" peerless:

Vifa TC6FC00-04 | HiFiCompass

The THD measurements at voltage levels 2.83 - 5.6 V were carried out with High Pass Filter "on" (2nd order Butterworth type, 200 Hz cutoff, HPF2-200)

hificompass.com

 

[bigjacko]

You can compare off-axis frequency responses here:

Tectonic TEBM46C20N-4B | HiFiCompass

The THD measurements at distance of 315 mm and voltage level 2.83 Volt were carried out with High Pass Filter "on" (2nd order Buttreworth type, 100 Hz cutoff, HPF2-100) The THD measurements at distance of 315 mm and voltage levels from 4 Volt to 5.6 Volt were carried out with High Pass Filter...

hificompass.com

A 1" tweeter is much neater up high:

Peerless BC25TG15-04 | HiFiCompass

hificompass.com

But the Tectonic is much better at 10K than a 2" peerless:

Vifa TC6FC00-04 | HiFiCompass

The THD measurements at voltage levels 2.83 - 5.6 V were carried out with High Pass Filter "on" (2nd order Butterworth type, 200 Hz cutoff, HPF2-200)

hificompass.com

I think if you want a full range driver to have good high end diectivity, BMR is very good. But if you only want it to be mid range, the directivity and the distortion is the same as the peerless T series drivers. BMR is more expensive than peerless T series, but we don't know how good is the qc on peerless.

 

[Davidpurton]

Still have 4 x Fane dml Mini Pro's...picked up new and boxed for £50 per pair when prejudice was at a peak! 100Hz -20KHz..80 watts and 88dB/watt. The spec is a bit of a stretch in truth and they benefit from eq...but the closest you could get to "single driver" with a dispersion of 165 deg H x about 120 deg V at all frequencies.

 

[Rhodo]

Just jumping in here since I was looking close at some desktop BMR passive speakers in my recent hunt for a new setup. Cambridge Audio makes a couple different compact BMRs in their "Minx" line, the 'min12' and 'min22'. Nice looking ultra compact desktop-ish format which physically would be prefect for a computer desk. Didn't end up buying them since I couldn't find any actual measurements and consumer reviews were all over the map from "god-tier" to "horrible tin cans"... Also wasn't excited to take a 320$ chance on them since I've heard the similarly tiny Drop BMR1 speakers and did not like them at all.

Edit: Found a picture of it sans covers on eBay.

Edit part 2: Almost forgot, there's also the Gallo SE line I looked at that use a "proprietary ultra-wide dispersion flat-diaphragm transducer" which sure sounds like a BMR or something similar. I can't find any images/info for the actual driver in them though so who knows.

 

[napilopez]

Note: why is this in the headphone forum? Can this be moved to the speaker forum?

Just jumping in here since I was looking close at some desktop BMR passive speakers in my recent hunt for a new setup. Cambridge Audio makes a couple different compact BMRs in their "Minx" line, the 'min12' and 'min22'. Nice looking ultra compact desktop-ish format which physically would be prefect for a computer desk. Didn't end up buying them since I couldn't find any actual measurements and consumer reviews were all over the map from "god-tier" to "horrible tin cans"... Also wasn't excited to take a 320$ chance on them since I've heard the similarly tiny Drop BMR1 speakers and did not like them at all.

Edit: Found a picture of it sans covers on eBay.
View attachment 345563

Edit part 2: Almost forgot, there's also the Gallo SE line I looked at that use a "proprietary ultra-wide dispersion flat-diaphragm transducer" which sure sounds like a BMR or something similar. I can't find any images/info for the actual driver in them though so who knows.

I've been researching small surround/atmos speakers mysel the past month or so, the Minx's in particular, searching desperately for measurements.

I finally found some of the smaller Minx12 in a youtube video:

Please note the super-squished scaling, but I mean, it could certainly be worse. Honestly, better than I expected; the overall trend is fairly flat. At 45 degrees, it's actually a little more linear, and you can see just how wide these things radiate.

It's barely changed below 10khz.

Given decent EQ, a sub, and a small listening space like many apartment theater setups(mine), I can see these being quite pleasing. I'm also curious about using them for digital piano setup. I have the iloud MTMs but find myself wanting even wider dispersion to better replicate the feel of a real piano.

Curious to see how the larger minx22 fare. Half tempted to buy one just to measure it...

Edit: Just so we're clear though, here's that measurement on closer to Amir's typical scale, which is itself more squished than I'd like:

 

[somebodyelse]

Just jumping in here since I was looking close at some desktop BMR passive speakers in my recent hunt for a new setup. Cambridge Audio makes a couple different compact BMRs in their "Minx" line, the 'min12' and 'min22'. Nice looking ultra compact desktop-ish format which physically would be prefect for a computer desk. Didn't end up buying them since I couldn't find any actual measurements and consumer reviews were all over the map from "god-tier" to "horrible tin cans"... Also wasn't excited to take a 320$ chance on them since I've heard the similarly tiny Drop BMR1 speakers and did not like them at all.

Edit: Found a picture of it sans covers on eBay.
View attachment 345563

Edit part 2: Almost forgot, there's also the Gallo SE line I looked at that use a "proprietary ultra-wide dispersion flat-diaphragm transducer" which sure sounds like a BMR or something similar. I can't find any images/info for the actual driver in them though so who knows.

Not the most in-depth of measurements, but more than I've seen anywhere else:
https://www.audiosciencereview.com/...enginerding-with-weeb-labs.21131/post-1689916