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Philharmonic BMR Speaker Review

Trouble Maker

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You mean in addition to the monitor, or instead of? If the former, it wouldn't be practical because I would have to meet a minimum order for two different BMR's with the same performance characteristics, and then pay more for the tower cabinet and shipping. I would rather save the tower approach for a premium version with deeper bass response and greater power handling. I should be getting a test cabinet for that in a few weeks.
I meant if I were to make them (cabinets) for myself, using the kit from Meniscus. Would the internal cabinet dimension changes have some significant negative effect, like internal resonances. I don't have a huge depth of knowledge in this area.

I'm struggling with the depth most speakers regardless of form factor not fitting well. Our living room is 12ftx20ft, so not huge. Due to layout the position of items are pretty much fixed, with the TV and speakers on the long wall. And also the main entrance is by the right speaker. My feeling is a shallow 2 or 'small' 3 way would work well for us. I would still plan to use this with a sub.
 
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I meant if I were to make them (cabinets) for myself, using the kit from Meniscus. Would the internal cabinet dimension changes have some significant negative effect, like internal resonances. I don't have a huge depth of knowledge in this area.

I'm struggling with the depth most speakers regardless of form factor not fitting well. Our living room is 12ftx20ft, so not huge. Due to layout the position of items are pretty much fixed, with the TV and speakers on the long wall. And also the main entrance is by the right speaker. My feeling is a shallow 2 or 'small' 3 way would work well for us. I would still plan to use this with a sub.
The internal cabinet dimensions (volume) affect the bass tuning. So you'd need the same volume or otherwise you'd be altering the bass response.

Altering the dimensions, but leaving the overall volume the same (for example by reducing depth but increasing height), would leave the bass tuning the same, but *could* affect unwanted resonances at the port output.

The tower speaker I showed before probably has a dividing wall inside, making the top half the same volume as the bookshelf BMR, with the bottom half of the cabinet being a separate, unused chamber.
 
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How good or bad of an idea is trying to turn this into a tower? Same internal volume but shrink foot print, mostly in the depth. I like the idea since it takes up less real estate, I personally like the aesthetics/ proportions better, and no need for a stand.
This would probably work if it weren't for the port - it's nearly as long as the speaker is deep. If you can make a custom curved port with the same length as the precision one used, it would probably be fine. Or maybe put the port on the bottom of the tower and make sure to raise up the bottom with feet or a plinth or something crazy.

The cabinet is also super damped behind the woofer, with not much space between the magnet and the damping material.

Those towers would have to be super tall and skinny though I'd think. Front width is non negotiable because of baffle edge stuff, so that's fixed at appx 8 inches. Looks like my cab is 12" x 8" x 20" for an internal volume of ~ 1920 in^3. I'm too lazy to use the internal dimensions, note. So if you wanted it 48" tall, it would only be 5" deep...
 
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Dennis Murphy

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Yes it was measured at one university. I don't know how to read the red line too because it is so low, nearly bottom of graph. Are you measuring the distortion yourself at home? Do you need special ways to measure it and how accurate would it be?
Measuring distortion is always part of the design process. I use OmniMic software for that, and it appears to be quite accurate down to 100 Hz.
 

EEG

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Hi!
New here.
I'm plannig to build a pair of BMR's.
Regarding th Meniscusaudio Kit ,I've made some researches and all the drivers are available in my country(Romania). To avoid high shipping costs from US(around 250$) it would be a much cheaper option to buy them from here. I have some questions although:
Any information about Scanspeak 18W8545K00? I.m asking because a guy with a lot of experience(mine is minimal) in DIY speakers said it finds that speaker a little better than the 01 version. Also the RAAL 64-10 is available here at 250$ , but the same person said that the new version might have a 4/8 ohms switch but he's not 100% sure about that.
The remaining problems , the cabinet/dumping , crossover/wiring , i'm not thinking at the moment because it would be another stress factor. There are too many theese days. I must start with something ,so the drivers first.
Edit: I worked 10 years as a sound engineer ,so my experience in audio is not as low as it is on the DIY side.
 

Dennis Murphy

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Hi!
New here.
I'm plannig to build a pair of BMR's.
Regarding th Meniscusaudio Kit ,I've made some researches and all the drivers are available in my country(Romania). To avoid high shipping costs from US(around 250$) it would be a much cheaper option to buy them from here. I have some questions although:
Any information about Scanspeak 18W8545K00? I.m asking because a guy with a lot of experience(mine is minimal) in DIY speakers said it finds that speaker a little better than the 01 version. Also the RAAL 64-10 is available here at 250$ , but the same person said that the new version might have a 4/8 ohms switch but he's not 100% sure about that.
The remaining problems , the cabinet/dumping , crossover/wiring , i'm not thinking at the moment because it would be another stress factor. There are too many theese days. I must start with something ,so the drivers first.
Edit: I worked 10 years as a sound engineer ,so my experience in audio is not as low as it is on the DIY side.
I'm not sure you're getting great information on the drivers. The 64-10 doesn't have a choice of impedance, and it shouldn't cost anything like $250, unless that's the price for a pair. Plus, it's an OEM driver, so I don't know why it would be available for general sale anywhere. Are you sure we're talking about the same tweeter? The 8545-01 woofer is the latest version, and it's parameters aren't the same as the older version, nor would its raw response be identical. So it would be pretty much a crap shoot if you used the old woofer.
 

EEG

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Thank you very much for the feedback.
Scanspeak 18W8545K00 is not the old model. It's different:
https://audio-hi.fi/download/pdf/Scan-Speak_18w-8545k00_Classic_midwoofer.pdf
https://audio-hi.fi/download/pdf/Scan-Speak_Classic_18W-8545-01_midwoofer.pdf
And the early version
https://audio-hi.fi/download/pdf/Scan-Speak_18w-8545-00_Classic_midwoofer.pdf
That's the place where I found the drivers, except for the Tectonics.
http://www.audioalchemy.ro/difuzoare/scanspeak/scanspeak.htm
http://www.audioalchemy.ro/difuzoare/raal/raal.htm
The 64-10 isn't listed there but you can spot him in the price list.
The xls files aren't alowed for atachements so i made a capture: RAAL.JPG
 

alexis

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The redline (THD) is on percentage scale on the right while all others are on dB scale on the left. Each HD is -40 dB from the test signal, and the THD percentage is low.

I believe that's the measurement that was done during an open house at a university-owned anechoic chamber. I've never understood the distortion graph--how can THD be lower than its components? The 64-10X RAAL is the only model available now in the 64 series. It has a different rear chamber that allows a slightly lower crossover point, or less distortion at the same Xover frequency. As I recall, my distortion readings at one meter, 90 dB were about .5 percentage points lower over the band where THD is highest (2-3 kHz). I'll have to run that again to make sure--I forgot to save the results.
 

Dennis Murphy

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Thank you very much for the feedback.
Scanspeak 18W8545K00 is not the old model. It's different:
https://audio-hi.fi/download/pdf/Scan-Speak_18w-8545k00_Classic_midwoofer.pdf
https://audio-hi.fi/download/pdf/Scan-Speak_Classic_18W-8545-01_midwoofer.pdf
And the early version
https://audio-hi.fi/download/pdf/Scan-Speak_18w-8545-00_Classic_midwoofer.pdf
That's the place where I found the drivers, except for the Tectonics.
http://www.audioalchemy.ro/difuzoare/scanspeak/scanspeak.htm
http://www.audioalchemy.ro/difuzoare/raal/raal.htm
The 64-10 isn't listed there but you can spot him in the price list.
The xls files aren't alowed for atachements so i made a capture: View attachment 74907
It's hard to see from the specs why the k version would be better. The 01's Fs is lower and its sensitivity is a little higher, which is a rare combination and better suited to the BMR, which is already a low-sensitivity speaker. In any event, the k would not be a drop-in replacement for the 01. Assuming you could actually source the 64-10 from that company, the pricing is, uh, creative. you would probably be better of seeing whether Meniscus could sell you the crossover kit + the 64-10X. Even with shipping, it might be cheaper than just buying the RAAL over there.
 

EEG

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Thank you again Mr Murphy.
I just figured out how that company can purchase the RAAL 64-10. They make their own speakers ,so the are able to get OEM-s. Or maybe just the fact the Serbia is nearby. Anyway the prices are truly "creative".
 

DDF

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Video review is up on youtube.
Thanks for all your great hard work. Your presentation is refreshingly balanced and lacking in exaggeration, maybe the best loudspeaker reviews I've ever come across. I like your choice of pragmatic objective measurements that matter, and rational subjective comments put into clear context. Looking forward to your tests.

Small suggestion, I couldn't find a link to your detailed web page with all the juicy bits, maybe add to the "about" section on youtube?
 
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hardisj

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Thread Starter #174
Thanks for all your great hard work. Your presentation is refreshingly balanced and lacking in exaggeration, maybe the best loudspeaker reviews I've ever come across. I like your choice of pragmatic objective measurements that matter, and rational subjective comments put into clear context. Looking forward to your tests.

Small suggestion, I couldn't find a link to your detailed web page with all the juicy bits, maybe add to the "about" section on youtube?
Thanks! After my first 3 videos I found some things I didn't like about them. So I changed things up a bit. I appreciate the feedback. That means a lot. :)

Also, the link is actually in the about section of that review. I'll pin it to the comments section, too, just so people don't miss it.
 

TimVG

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BMR Philharmonitor EQ correction filters:

1595774381291.png



Original vs corrected response (on axis, listening window, estimated in-room response)

bmrcomp.png
 

Trouble Maker

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@hardisj
Is that speaker the same width on the front as the Salk Sound? Do you have any more info on that build, maybe the builder has a build thread somewhere? Maybe it's a visual trick due to proportions, black or more rounded edge front baffle, but it looks a little skinnier than the current Salk Sound BMR.

This would probably work if it weren't for the port - it's nearly as long as the speaker is deep. If you can make a custom curved port with the same length as the precision one used, it would probably be fine. Or maybe put the port on the bottom of the tower and make sure to raise up the bottom with feet or a plinth or something crazy.
That is really good info, I had not seen the port was that long. I gather it is 2"x8"?
How about a slotted port on the front bottom of the speaker? I think at the depth of the speaker I'm targeting it would need to 'bend' up the back a little. I'm fairly competent at woodworking, I would be able to make this. I'm imagining creating curves on any transition points and maybe even in the corners of the port (looking at the cross section), square edges seem like a bad idea on any ports. My image is to make the same cross section and length as the current port. Another idea is the use the 'diagonal' space in the base and I might not even need to turn it up the back. I don't like this as much due to aesthetics and symmetry, but could be easier to construct. My image about front port would be better since I plan to place them close to the wall.


The cabinet is also super damped behind the woofer, with not much space between the magnet and the damping material.
Any good images that you know of for the damping? I can't seem to find any to understand or come up with an idea for a solution? If it's what I'm imagining, maybe carve our a place in the damping for the speaker? It doesn't seem ideal, but from a damping standpoint the best I can think of for a shallower cabinet depth. Depending on the specifics I could see this causing some heat rejection issues for the speaker (magnet) when driven hard for long periods.

Those towers would have to be super tall and skinny though I'd think. Front width is non negotiable because of baffle edge stuff, so that's fixed at appx 8 inches. Looks like my cab is 12" x 8" x 20" for an internal volume of ~ 1920 in^3. I'm too lazy to use the internal dimensions, note. So if you wanted it 48" tall, it would only be 5" deep...
It's also pretty easy to calculate internal and talk about reasonable speaker heights for a speaker this size. I think both of these are pretty important even if we are just in paper napkin world at this point. My image is usually 48" talk speakers are semi-monsters with much more driver area, higher output like the Revel Salon 2's. Any of the smaller towers I can find are usually in the 40-42" tall range. This probably still gets the tweeter at a reasonable (ear) height.

External (for the Salk Sound BMR) are 8" x 20" x 12.5" (WxDxH), so 2,000 in^3. So assuming 3/4" sides we get 6.5" x 18.5" x 11" =1322 in^3. That's a huge difference.

If we keep the 8" width but go to an 8" depth we get 33.5" tall. Probably needs to be a bit taller.
If we go to 40" tall we get about 6.75" deep, that actually doesn't seem bad to me.

Another idea I had was to 'separate' out the tweeter and BMR into a smaller (footprint) upper enclosure. Would probably be about 10" tall, leaving 30" for the woofer enclosure. My rough calculations are about an 8" square footprint for the woofer enclosure. I think at this point I would want to look up the woofer displacement and do some actual calculations/drawings. I'm really liking this idea. My image is the front baffle, back, top (twetter/BMR) enclosure in black with lower woofer enclosure sides and top finished. I think the smaller top enclosure in black would also shrink the visual footprint too as well as possible have some beneficial acoustic side effects (smaller baffle for mid/BMR).

I would probably make a plinth or some 'feet' that extend past the base an inch or an inch and a half bigger to give it some stability, this will also add some height possibly reducing the cabinet height above by an inch or two.
 

Dennis Murphy

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@hardisj


That is really good info, I had not seen the port was that long. I gather it is 2"x8"?
How about a slotted port on the front bottom of the speaker? I think at the depth of the speaker I'm targeting it would need to 'bend' up the back a little. I'm fairly competent at woodworking, I would be able to make this. I'm imagining creating curves on any transition points and maybe even in the corners of the port (looking at the cross section), square edges seem like a bad idea on any ports. My image is to make the same cross section and length as the current port. Another idea is the use the 'diagonal' space in the base and I might not even need to turn it up the back. I don't like this as much due to aesthetics and symmetry, but could be easier to construct. My image about front port would be better since I plan to place them close to the wall.
I would avoid a front slotted port if at all possible. They don't work as well as the flared Precision Port and can be tricky to implement (see Amir's review of the Salk WOW1). Jim Salk offered a slotted front port for the BMR, but I always advised people who wanted one to get the 1.0 cu ft cabinet instead of the .75 in order to keep bass performance roughly equivalent. As a compromise, you might try the Precision Port without the internal flare, or even a non-flared port. The flares add about 1.5" to the necessary overall length of the port. So a simple tube would only need to be 6.5" long, or a little over 7" for one flare. You don't need a lot of open space behind the cabinet to make the rear port work properly. Maybe 4".
 
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You don't need a lot of open space behind the cabinet to make the rear port work properly. Maybe 4".
While we're on the subject, what would you consider to be the optimal setup for these? Let's say, distance from rear walls, side walls, each other, and the listener?

Thanks!
 

Chromatischism

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Yep, there are two relevant quotes from the Olive preference paper part II.

First, there's this one, which we've talked about a couple of times around here:

The degree of tilt varies among curves for Test One and the larger sample. Test One includes mostly 2-way designs whereas the larger sample includes several 3-way and 4-way designs that tend to have wider dispersion (hence smaller negative target slopes) at mid and high frequencies. This suggests that the ideal target slope may depend on the loudspeaker’s directivity.

Emphasis mine. And then there's this other choice quote that I do not think has been discussed here as much:

The speakers with the flattest sound power had rising frequency responses on-axis and/or reduced low frequency extension. Both are necessary compromises to achieve flat sound power for speakers that have a rising directivity at higher frequencies. Such speakers represent the vast majority of all speakers sold. A speaker with constant, flat directivity could theoretically satisfy the flat sound power criterion and still achieve high preference ratings, so long as it had a smooth on-axis response well-maintained off-axis. However, such speakers are not widely available."

Here Olive goes a bit further, indirectly but clearly saying that the target slope of the PIR is possibly/likely contingent upon the directivity. In other words, constant directivity designs like the D&D 8C and very wide direcitivty designs, which essentially approach constant horizontal directivity, likely do not need the -1dB per octave slope.

I do think wide directivity may contribute a little to brightness, especially in a small reflective room, but most of the flat slope is heard as an expanded soundstage/larger apparent sources rather than brightness. I wonder if it would be the opposite of a speaker had very wide vertical directivity though. I'm betting it would.
Sounds like we need to come up with an offset value for PIR based on some kind of average dispersion width value.
 

Trouble Maker

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I would avoid a front slotted port if at all possible. They don't work as well as the flared Precision Port and can be tricky to implement (see Amir's review of the Salk WOW1). Jim Salk offered a slotted front port for the BMR, but I always advised people who wanted one to get the 1.0 cu ft cabinet instead of the .75 in order to keep bass performance roughly equivalent. As a compromise, you might try the Precision Port without the internal flare, or even a non-flared port. The flares add about 1.5" to the necessary overall length of the port. So a simple tube would only need to be 6.5" long, or a little over 7" for one flare. You don't need a lot of open space behind the cabinet to make the rear port work properly. Maybe 4".
Thank you for replying despite my relatively limited knowledge in this area!

4" while quite reasonably small compared to the typical 'must be 3' into the room' is something when I start to add up all of the #s in my head, 12.4" deep, at least 4" into the room, now we have a speaker that is sitting almost a foot and a half into the room, 3 or 4' after the main entrance, so you open the door and there is basically a speaker right in front of you. Everything I'm trying to do in our house is a game of efficiency to make ~11xx sq ft feel and live a lot bigger than it actually is, so we can have many friends and family over! Every inch counts, especially in some critical areas.

1595831231184.png


1595831241277.png


What is your best estimation about reasons for problems with slot ports e.g. strange proportions, too many discontinuities (square edges), front port generally a problem? Again, I'm fairly good at woodworking so I'm imagining and can make a port that looks like something between a traditional port and what most slotted ports look like.

Flares are critical in which area? I assume at high output at port tuning frequency i.e. high airflow/volume makes high airspeed, so if this were used with sub probably not as big of a concern to not have flares since the port tuning frequency is relatively low in this? But then the same port (characteristic) is still necessary to get the correct cabinet mechanical system characteristics for the woofer?

It's starting to seem like I'm chasing down the wrong rabbit hole, but at least I'm learning something!
 
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