BMS 15n820 - AVS Forum
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post #1 of 22 Old 11-17-2013, 10:14 AM - Thread Starter
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Greetings! I recently ordered 2 x BMS 15n820's, and im wondering if anyone could help me design a cabinet for them. I would like to use them as "midbass bins", tuned to around 50hz. I would prefer to have a slot port at the front, if possible. Can this be done ?

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post #2 of 22 Old 11-17-2013, 11:58 AM
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Hello Anders,

Something like this should work for you.



~3.2cuft net internal built from 1/2" material (add 1/2" to overall dimensions for 3/4"). 2" high slot port across the front with a single brace running down the middle, the port length should be about 6.5" which should put tuning right around 50hz. Port velocity and cone excursion will be kept within safe limits up to 500W input power with a highpass filter at 45-50hz.

If you want both in one cabinet just double the width of that one using three braces in the port and don't forget to brace either cabinet as well.
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post #3 of 22 Old 12-04-2013, 10:35 AM - Thread Starter
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post #4 of 22 Old 12-04-2013, 12:29 PM - Thread Starter
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post #5 of 22 Old 12-13-2013, 02:36 PM - Thread Starter
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post #6 of 22 Old 12-13-2013, 02:48 PM
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Coming along nicely
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post #7 of 22 Old 12-14-2013, 03:48 AM
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Oh my, I just looked up the specs on that BMS 15n820 that you have there. Looks like a very good mid-bass woofer! Did you consider any other drivers before deciding on the 15n820's? I wonder how it would stack up against the JBL-2226 or 2225, or possibly even the similar prices AE TD18 or the cheaper TD15?

I think you probably could have gotten the TD18h cheaper than the 15n820 if you paid retail for the BMS. But I am going to guess that you live overseas so that might not be the case.
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post #8 of 22 Old 12-15-2013, 01:18 PM - Thread Starter
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post #9 of 22 Old 12-15-2013, 02:30 PM
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They look great how about the sound?
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post #10 of 22 Old 12-15-2013, 04:44 PM
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Nice job! Are those p-39 towers?

My dual sealed LMS 5400 Ultra build
http://www.avsforum.com/forum/155-di...0-build-4.html
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post #11 of 22 Old 12-15-2013, 06:53 PM
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Aww! Those Palladiums look nice! Cost a pretty penny too!
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post #12 of 22 Old 12-16-2013, 12:28 AM - Thread Starter
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Yes p39f. Sounds great
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post #13 of 22 Old 12-16-2013, 07:29 AM
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Do you feel the p39's lack in the mid bass dept, and that's why your adding the BMS? Although not in the same league as the p39's, I have the RF-83's, and to me they don't have much mid bass punch. I have always been curious how the Klipsch palladums sound.

My dual sealed LMS 5400 Ultra build
http://www.avsforum.com/forum/155-di...0-build-4.html
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post #14 of 22 Old 12-17-2013, 12:38 AM - Thread Starter
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I have 2 lms ultra thats why i need the bms
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post #15 of 22 Old 12-17-2013, 04:04 AM
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Quote:
Originally Posted by SeekingNirvana View Post

Do you feel the p39's lack in the mid bass dept, and that's why your adding the BMS? Although not in the same league as the p39's, I have the RF-83's, and to me they don't have much mid bass punch. I have always been curious how the Klipsch palladums sound.

While I can not speak for the OP, I have spent a good bit of time listening to the Palladiums in my local dealers showroom. To me, they have good clarity, detail and an overall nice top end. The mid-bass is pretty nice as well. I have spent a lot of time comparing the B&W 805D2 to the Klipsch Palladium bookshelf monitors, and while I can't say which one I like best, (they both have their own strong points), the Palladium bookshelf monitors have a ton more punch, output, and overall better mid-bass than the 805D2!
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post #16 of 22 Old 12-17-2013, 04:05 AM
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Quote:
Originally Posted by anders1234 View Post

I have 2 lms ultra thats why i need the bms

I am confused? What does having two top of the line subwoofers have to do with needing the BMS mid-bass cabinets??
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post #17 of 22 Old 12-17-2013, 06:08 AM - Thread Starter
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The ultra woofers are so strong at low frequency . Need some more punch
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post #18 of 22 Old 12-17-2013, 06:27 AM
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Those LMS-Ultras should have some pretty nice mid-bass punch, although I can certainly relate to wanting more as I have duel MartySubs with Dayton HO18's and a single MFW-15, and I still desire more mid-bass, which I plan on addressing with either 3 JBL-2226's or 2 of the AE TD18's, depending on my cash flow next month.

Have you tried EQ'ing your subs to have a little boost around the 60hz to 120hz area?
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post #19 of 22 Old 12-17-2013, 08:32 AM
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First, that image of the Palladiums, the Mc, the hammer, printer, etc, is one fascinating image. It's got quite the eclectic array of items cool.gif
Quote:
Originally Posted by anders1234 View Post

The ultra woofers are so strong at low frequency . Need some more punch

Interesting ... have you considered the room acoustics? It's entirely possible you already possess sufficient SPL capability, however there's SBIR issues lessening the energy in all the wrong freqs. Do you have measurement capability?

Seeing all the nice gear, you may or may not already know all this. No offense if you do.

Subjective punch and impact reside entirely within the heart of the SBIR (speaker boundary interference response) range. Quarter wave interactions can easily suck the impactful energy out of a presentation. To know for sure, one must measure. However, simply moving around while a powerful track or movie effect is playing will allow you to determine if some locations adjacent to your LP have more impact than others.

With adequate bass trapping, you lessen the blurring time related bass "overhang", this allows greater transient delineation to be experienced. It's typically not the initial transient, it's the problematic excess of energy that doesn't dissipate quickly enough ... this is often what many perceive as lacking punch, etc. Trapping also smoothes the FR, always a positive step.

Also, the rear wall bounce, and our seating location in general can have even a greater impact than the time related effects I mention above. Never sit in the center of the room, front to back, .. this is a null zone. Often 38% off the front wall, or rear wall is a solid starting location for seating.

Another consideration is time alignment. Improper time alignment between the subs and mains will null the critical range you're interested in. So yeah it's a minefield, that's why without measurements, you're flying blind. Quarter-wave nulls, SBIR, proper time/phase integration between subs and mains, excessive bass decay in the room, room modal issues, everything's got to fall into place.

As I said, you may or may not be aware of these items. All said, there's few things as punchy as the aptly powered pro-audio LF driver, in a well executed environment/system.

Good luck

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post #20 of 22 Old 08-16-2014, 08:06 AM - Thread Starter
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post #21 of 22 Old 08-16-2014, 08:07 AM - Thread Starter
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post #22 of 22 Old 08-16-2014, 10:37 AM
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Quote:
Originally Posted by anders1234 View Post
Ohh snap!
And what might you be doing with those?
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