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[Too Tall (Curtis H. List)]

Art Welter wrote on Mon, 25 January 2010 20:55

Too Tall, Interesting charts! Could you post charts for frequency response and phase for the two coax monitors? Art Welter

Hi Art,

By rights I should not have posted the 12CN680 coax since it has just started beta. It could change and then I have two versions out there.

The 15C682 is set in stone so I can post some on that.



The top is a pic of it setting on some milk crates putting the speaker about 4 feet in the air and the mic 1 meter from the baffle.

This shows the true absolute sensitivity. (About 95dB)
The one ground wedge is wrong since the mic was further away. Also no compensation for 1 volt input.

On the ground wedge you can see the cancellation from the floor reflection in the 150Hz to 300hz range. You can plainly see it on the phase response.

NOTE: I have heard some people put some foam or other sound absorption material in front of the box to soak up the floor bounce.
At a wavelength of over 45 inches for 300hz you can forget about it having any useful effect.The most it can do is delay the sound a bit. It won't soak it up enough to make a difference.
Now if some 3kHz finds its way around the side that would make a difference, but the baffle or horn with stop that from happening.

[Too Tall (Curtis H. List)]

Art Welter wrote on Mon, 25 January 2010 20:55

Too Tall, Interesting charts! Could you post charts for frequency response and phase for the two coax monitors? Art Welter

Speaking of absorbing reflections here are some pictures of the driver and box for the 15C682 (60-degree conical horn).

Here is the driver by itself, the speaker sitting on its side 48 inches in the air and sitting as a wedge on some milk crates.



I would have to dig some, but the foam we put behind the horn has a HUGE effect on frequency response and clarity.
Without the foam the best xover design (active DSP or passive) sound mediocre at best. All the digital delay or EQ in the world will not fix it.

[Art Welter]

Too Tall,

Yep, that blue foam on the UREI co-ax horn wasn’t there just to make them look good.
That extra reflected/delayed 1K stuff off the back of the HF horn really does not “enhance the presentation”.

Thanks for posting the graphs. Makes me feel better about my 2x8” with tweeter monitors to see some real world tests that have not been massaged flat.

What is the stuff you are using on the back of the 40x80 horn? Kind of looks like a knitting project   .

Art Welter

[Too Tall (Curtis H. List)]

Art Welter wrote on Tue, 26 January 2010 15:56

Too Tall, Yep, that blue foam on the UREI co-ax horn wasn’t there just to make them look good. That extra reflected/delayed 1K stuff off the back of the HF horn really does not “enhance the presentation”. Thanks for posting the graphs. Makes me feel better about my 2x8” with tweeter monitors to see some real world tests that have not been massaged flat. What is the stuff you are using on the back of the 40x80 horn? Kind of looks like a knitting project   . Art Welter

It was.
BMS ships the 12CN680 coax that a knit sausage (No, Really!) to knock down the reflections from the woofer. The trouble was the material is not thick enough to do the entire job.

I tried several different materials, but nothing worked.
The problem is the horn is too short so there is very little space to get a thick piece of foam behind the horn like I did with the BMS 15C682.
In that I used 1" foam.
If I tried 1" foam with the 12" coax it would hit both the horn and the driver cone.

the only real solution is for BMS to make a deeper horn that created more space behind the horn.

So I tried many types of material hoping to get lucky, and I did.
leave the knit material and open it up so you can stuff the inside with the batting they use for the inside of quilts.

So  for every driver that comes in Jack opens up the knit material, stuffs it with batting and closes it back up.
Works like a charm.

[Michael Strickland]

I was just going to make a post asking why I don't see these BMS drivers around. Looks like they're finally getting some attention. On paper, these things look like beasts! High power, high efficiency, low weight, complete phase coherency...

What's the pricing on the 15" Triaxial? Do they sound as good and get as loud as they spec out?

[Jack Arnott]

Michael Strickland wrote on Wed, 03 February 2010 18:58

I was just going to make a post asking why I don't see these BMS drivers around. Looks like they're finally getting some attention. On paper, these things look like beasts! High power, high efficiency, low weight, complete phase coherency... What's the pricing on the 15" Triaxial? Do they sound as good and get as loud as they spec out?

Hello Michael

Cost on that is $950.00.

I have not used this unit. I do use the mid high unit extensively, and have just started to use the coaxial 12".
And I sell it too, so my (very high) opinions are open to interpretation/scrutiny.

On to BMS/Attention.

I started a long (not for me) reply to this part, but it seemed pointless. Short answer (for me), they are doing good. Both in the US, and more so abroad. Even last year my BMS sales were up. The one exception is this very (LAB readers/individual providers) market. Which used to be a surprise to me, as I thought this would be my big in when I started in sales. If you want more explanation, ask.

At times I feel that this board can run a bit heavily populated, eastern USA seaboard centric. One of my favorite TV shows a couple of years ago was the ill fated Studio 60. In one episode a cast member is being detained in a rural Nevada jail. The supposed rube sheriff is played by John Goodman. He has a line to the show producer how, "You TV types think that nothing exists between Madison Avenue and Hollywood Blvd." And that rang heavily to me. Both from an entertainment standpoint; the X-Files was the one show where they were constantly going to rural areas, and the residents were always typical TV hicks. And from a business standpoint. It's not that I don't ship to LA and NYC, but from a population density standpoint the numbers are low.

But home hifi, home entertainment, speaker company, paging, movie editing, noise testing, even car and boat systems, etc. markets keep moving forward.

Regards, Jack Arnott

[Jack Arnott]

While I am proud to represent BMS, and think that they are the best sounding drivers in my small world, in reality I do nothing in this project other than import and sell. So lest this turn into a BMS love fest, I would like to tout the abilities of Curtis.

Who is the best practical use crossover designer in the (my small) world. (With apologies to Tom.)
So when Weogo and I are going to our gigs with no EQ for the monitors, and running from our board to amp to speaker. And not needing to deal with any controllers, or making sure the highs match the lows, only that we have signal; it is not because BMS has the flattest frequency response. It is because of Curtis' crossover designs, and his due diligence. So, more than to just toot his horn on this project, you should know that although he is my crossover guy, he could also be your crossover guy.
Not a very thought of person in the live audio chain, but keep it in your mind for future projects.

Regards, Jack

[Al Limberg]

+2

?;o)
Al

[Tim McCulloch]

Jack Arnott wrote on Thu, 04 February 2010 16:46

While I am proud to represent BMS, and think that they are the best sounding drivers in my small world, in reality I do nothing in this project other than import and sell. So lest this turn into a BMS love fest, I would like to tout the abilities of Curtis. Who is the best practical use crossover designer in the (my small) world. (With apologies to Tom.) So when Weogo and I are going to our gigs with no EQ for the monitors, and running from our board to amp to speaker. And not needing to deal with any controllers, or making sure the highs match the lows, only that we have signal; it is not because BMS has the flattest frequency response. It is because of Curtis' crossover designs, and his due diligence. So, more than to just toot his horn on this project, you should know that although he is my crossover guy, he could also be your crossover guy. Not a very thought of person in the live audio chain, but keep it in your mind for future projects. Regards, Jack

I don't want to jinx brother List by calling him an 'audio treasure', so I won't.  Nope, didn't do it.

The gear you demo'd for me sounded very good, very hi-fi in a non-hyped way.  The crossovers were something I didn't think about until you showed me Curtis' work: robust as well as spot on for the drivers.

Your collaboration with Curtis works well.  It will be interesting to hear your next project.

Have fun, good luck.

Tim Mc

[Weogo Reed]

Hi Y'all,

Here are some pics of the BMS 12" coax wedges at a small Contra dance gig:

http://tinypic.com/useralbum.php?ua=mlfN44TZSRpDiTH9Ac33Iw%3 D%3D

Thanks and good health,  Weogo