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Can we discuss the BMR Tower?

Kachda

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You'd pick different components while keeping the BMR driver, I assumed that was pretty obvious from my post.
Isn’t one of the strengths of this speaker the even dispersion of the raal tweeter (which is the costliest component). A different tweeter may possibly jeopardize that, but I’m no expert. I’m sure however that Dennis didn’t choose this tweeter for how much it cost
 
D

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Isn’t one of the strengths of this speaker the even dispersion of the raal tweeter (which is the costliest component). A different tweeter may possibly jeopardize that, but I’m no expert. I’m sure however that Dennis didn’t choose this tweeter for how much it cost

I don't want a Philhamonitor BMR for cheaper. I just want a speaker design that utilizes the BMR driver in a 3 way design that uses different drivers for the tweeter and woofer, as well cutting down costs on the xovers (you can save a lot of money not using boutique caps for instance). I don't really care about the tweeter or the woofers, I'm just interested in the impressive dispersion of the BMR driver. I might as well give this a try myself.
 

R Swerdlow

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Second--and not addressed to you--I thought this was a science forum. All these comments about aesthetics make me think you guys thought you were posting on AVS. But since I have your attention, the grill design has proven as problematic as Middle East politics. A one-piece grill is prone to shipping damage and will cover a lot of the veneer. So far I haven't been able to come up with a 2-piece design that looks right. The first draft had an oval upper grill that along with the woofer grill looked like an exclamation point. So I got rid of the oval. It's still kind of klunky. Any suggestions are welcome. As for the "oddly spaced drivers," that's what you get when you optimize the woofer and port locations to maximize the quarter wave contribution, and squeeze the MTM configuration as close together as possible. It's called form following function, or more succinctly, science. :)
Hilarious:)
I agree, this is hilarious.

The criticism of a speaker's appearance (I don't think they've seen it with the grills), combined with those vocal few who can't stop complaining about MTM speakers, strikes me as yet another case of …

Too many scientists.png
 

R Swerdlow

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At nearly $400, the cost of the project just kind of kept going up and at the prices I was at, it was just smarter for me buy a premade speaker. There was also the chance that I wouldn't like them and I'd be stuck trying to sell a DIY speaker. I also didn't possess the tools to make the BMR driver cutout look up to my standards.

I'd like to see someone come up with a design that uses the BMR driver and woofer + tweeter for say, $500 a pair for the kit.
Someone did previously come up with 2-way design, combining a 6½" woofer with a BMR driver as a tweeter. If I remember correctly, that speaker, the Cambridge Audio Aero 2, sold for about $500 a pair. It's woofer was good, but using the BMR driver as a tweeter was not good.

There was some buzz on AVR that the Aero 2 would sound good only after many hours of breaking in. That was eventually dispelled (see link).
https://www.avsforum.com/threads/cambridge-aero-2-bookshelf-speaker.1504045/page-10#post-24151129.

Dennis Murphy's measurements also showed how the BMR driver failed as a tweeter. It was easy to hear that, but those measurements clearly documented it. However, he did get something positive out of all that. He thought the BMR driver did have promise as a mid-range driver. It took some effort before that idea was properly implemented, but the results of that mid-range as a 3-way design are indeed excellent.
 
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alexis

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Someone did previously come up with 2-way design, combining a 6½" woofer with a BMR driver as a tweeter. If I remember correctly, that speaker, the Cambridge Audio Aero 2, sold for about $500 a pair. It's woofer was good, but using the BMR driver as a tweeter was not good.
https://www.avsforum.com/threads/cambridge-aero-2-bookshelf-speaker.1504045/page-10#post-24151129.

Dennis Murphy, however, did get something positive out of all that. He thought the BMR driver did have promise as a mid-range driver. It took some effort before that idea was properly implemented, but the results of that mid-range as a 3-way design are indeed excellent.

I have BMR as a single driver as my Dolby Atmos height speakers. I added a BSC circuit to give it proper frequency response. It was tiny so I can use 3M stickers to mount them on the ceiling. It doesn't have the Phil BMR magic...
 

MarkS

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Well, real men don't use grills. But those reflections are actually quite benign..
I don't think this is true (grills being benign that is), and so I went in search of generic grill on/off measurements, and found this:
https://www.audioholics.com/loudspeaker-design/grilles
Any comments on Figure 8?

In general, this would seem to show that grills can induce as large deviations (5 db) as are usually declared unacceptably poor here at ASR.

The situation in my own household is that bare drivers are visually unacceptable, and thus I have always sought out speakers specifically designed to sound best with grills on (currently Goldenear, previously DefTech).
 

muad

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I don't think this is true (grills being benign that is), and so I went in search of generic grill on/off measurements, and found this:
https://www.audioholics.com/loudspeaker-design/grilles
Any comments on Figure 8?

In general, this would seem to show that grills can induce as large deviations (5 db) as are usually declared unacceptably poor here at ASR.

The situation in my own household is that bare drivers are visually unacceptable, and thus I have always sought out speakers specifically designed to sound best with grills on (currently Goldenear, previously DefTech).
I don't think he was talking about direct measurements, but the overall sound power. We need MMM measurements with the grill on and off to see this.
 

Dennis Murphy

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I don't think he was talking about direct measurements, but the overall sound power. We need MMM measurements with the grill on and off to see this.
Right. I don't want to post a bajillion plots, but just to give you an idea of what I was referring to, here's a plot of the previous generation BMR on axis with the grill in place. The second plot is taken 30 degrees off axis horizontally. If I posted plots further off axis, the various peaks and dips would be all over the place.
BMR With Grill On Axis.png
BMR With Grill 30 degress Off Axis.png
 

Martin

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I have BMR as a single driver as my Dolby Atmos height speakers. I added a BSC circuit to give it proper frequency response. It was tiny so I can use 3M stickers to mount them on the ceiling. It doesn't have the Phil BMR magic...

I've thought the discontinued Cambridge Audio Aero 3 would make an excellent surround for use with a BMR home theater:
71gkZqo81lL._AC_SL1500_.jpg


Martin
 

Ericglo

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At nearly $400, the cost of the project just kind of kept going up and at the prices I was at, it was just smarter for me buy a premade speaker. There was also the chance that I wouldn't like them and I'd be stuck trying to sell a DIY speaker. I also didn't possess the tools to make the BMR driver cutout look up to my standards.

I'd like to see someone come up with a design that uses the BMR driver and woofer + tweeter for say, $500 a pair for the kit.

According SH, the flat packs are $330 a pair. They come with the driver cutouts from what I can see. It kind of defeats the purpose of a flat pack if they didn't. Meniscus charges $1000 for a full kit. Upgrading caps and resistors would cost extra. Dennis would have to answer whether it is worth it or not.

All of that said, I think when Dennis first posted pics of the new cabinets I said the delta between a prebuilt and DIY wasn't great. It would be better to spend the extra $300 or so on a completed speaker. Unless pricing has changed, I think that is still the best course of action.

I do agree about seeing the BMR driver with different drivers.
 

Dennis Murphy

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I don't want a Philhamonitor BMR for cheaper. I just want a speaker design that utilizes the BMR driver in a 3 way design that uses different drivers for the tweeter and woofer, as well cutting down costs on the xovers (you can save a lot of money not using boutique caps for instance). I don't really care about the tweeter or the woofers, I'm just interested in the impressive dispersion of the BMR driver. I might as well give this a try myself.
We don't use "boutique" crossover components. There wouldn't be any way to cut the crossover cost unless I used NPE caps, and then my email box would fill up immediately with irate messages. I guess the closest thing to what you're thinking of would be, say, the 3/4" SB Acoustics dome tweeter and a $40 woofer of some kind. That would put the total driver cost at around $160/pair. The crossover board would probably be just as expensive since the BMR driver needs a lot of components to achieve smooth roll-offs at both ends. If you want to build be a mule box, I would be happy to design the crossover.
 
D

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We don't use "boutique" crossover components. There wouldn't be any way to cut the crossover cost unless I used NPE caps, and then my email box would fill up immediately with irate messages. I guess the closest thing to what you're thinking of would be, say, the 3/4" SB Acoustics dome tweeter and a $40 woofer of some kind. That would put the total driver cost at around $160/pair. The crossover board would probably be just as expensive since the BMR driver needs a lot of components to achieve smooth roll-offs at both ends. If you want to build be a mule box, I would be happy to design the crossover.

I was referring to the meniscus kits with the audyn caps.

I suppose I could be a guinea pig for this build. That's around $320 in drivers, think the xover can fit inside an additional $180?
 
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Audyn caps are among the least expensive available. They are entry level, although easily of sufficiently high quality.

Huh figured they were pricey. Red with fancy print always makes me think 'spensive.
 

Kachda

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I was referring to the meniscus kits with the audyn caps.

I suppose I could be a guinea pig for this build. That's around $320 in drivers, think the xover can fit inside an additional $180?
Go for it, we will cheer you from the sidelines :). But if you use a dome tweeter and put it instead of the RAAL, how would you control the dispersion without a waveguide ?
 

thewas

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Someone did previously come up with 2-way design, combining a 6½" woofer with a BMR driver as a tweeter. If I remember correctly, that speaker, the Cambridge Audio Aero 2, sold for about $500 a pair. It's woofer was good, but using the BMR driver as a tweeter was not good.

There was some buzz on AVR that the Aero 2 would sound good only after many hours of breaking in. That was eventually dispelled (see link).
https://www.avsforum.com/threads/cambridge-aero-2-bookshelf-speaker.1504045/page-10#post-24151129.

Dennis Murphy's measurements also showed how the BMR driver failed as a tweeter. It was easy to hear that, but those measurements clearly documented it. However, he did get something positive out of all that. He thought the BMR driver did have promise as a mid-range driver. It took some effort before that idea was properly implemented, but the results of that mid-range as a 3-way design are indeed excellent.
The problems of the BMR at the upper octave can be observed also at the 2000€ Q Acoustics Q Active 200

1619126775150.png


Source: http://avmentor.gr/reviews/2021/q_acoustics_active_200_2.htm

I really don't understand how someone experienced like Fink Audio (who does the engineering for Q Acoustics and some other known brands) didn't hear this problem, when it was even immediately obvious to an amateur PA guy I know when he experimented with the driver.
 

Dennis Murphy

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I was referring to the meniscus kits with the audyn caps.

I suppose I could be a guinea pig for this build. That's around $320 in drivers, think the xover can fit inside an additional $180?
The problems of the BMR at the upper octave can be observed also at the 2000€ Q Acoustics Q Active 200

View attachment 125686

Source: http://avmentor.gr/reviews/2021/q_acoustics_active_200_2.htm

I really don't understand how someone experienced like Fink Audio (who does the engineering for Q Acoustics and some other known brands) didn't hear this problem, when it was even immediately obvious to an amateur PA guy I know when he experimented with the driver.

Whoa--are those true active speakers with dsp correction? If so, why wouldn't they just dial that junk out?
 
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