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The BMS group buy thread!!! - Page 4

post #91 of 482
2/10/13 at 5:08pm
Thread Starter 
Quote:
Originally Posted by tsloms View Post

I see that on their website they show a 4593ND and a 4594ND. The specs for them are nearly identical.

Does anyone know what the difference is and which one is better?

I can't tell you what the difference is, but I can tell you that Jack Arnott was very clear with me about the 4594 being the better unit.
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post #92 of 482
2/11/13 at 7:21am
the 4593 appears to have an upgraded top end. the 3rd order distortion numbers are much lower.

the 4593 also appears to have some sort of suckout around 4.5 khz.

otherwise, i can't find any differences.

who is jack arnott?
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post #93 of 482
2/11/13 at 8:03am
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

the 4593 appears to have an upgraded top end. the 3rd order distortion numbers are much lower.

the 4593 also appears to have some sort of suckout around 4.5 khz.

otherwise, i can't find any differences.

who is jack arnott?

Jack is the BMS rep for North Amercia. His comment to be was that the 4594 was the better unit of the two. Not sure of anything further than that.
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post #94 of 482
2/12/13 at 7:59am
Tried to call in my order yesterday. Got voice mail.... will try again today. I was thinking of getting waaaaay too much stuff to play with.... then did a reality check as to what was humanly possible over the next couple years given my extremely tight schedule and lack of free time. So just going to get one pair of 4592 2" exit coaxial CDs for the iwata-300 horns on order and one pair of 4595 1.5" exit coaxial CDs to try on SEOS-24s on order. So I'm contributing $2886 MSRP to the $10K minimum to hit the discounted price...
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post #95 of 482
2/12/13 at 10:01am
Quote:
Originally Posted by WiSounds View Post

Hmm. +/- 19mm?

http://bmsspeakers.com/index.php?id=18n862_overview


Tested in Voice coil magazine Feb 2012, measured really well!
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post #96 of 482
2/12/13 at 11:05am
Interesting story is that I now possess the pair of drivers that Vance tested.
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post #97 of 482
2/12/13 at 12:09pm
Quote:
Originally Posted by ChopShop1 View Post

Jack is the BMS rep for North Amercia. His comment to be was that the 4594 was the better unit of the two. Not sure of anything further than that.

JTR uses the 4593 in the Noesis (I'm about 95% certain based on a pic). It could be due to cost considerations but I doubt there would be much savings and if it was significantly inferior I doubt he would use it. How much cheaper is it? The 4594 looks better on paper to me.

HTDoc - short of a Truextent beryllium in a JBL or Radian 95x, or a TAD 4003 I'm not sure you can find a better driver for the 1.4,1.5 or 2" horns. It is definitely the best value with this group buy. The only downside is the need to design a crossover.

Ricci- Do you have a link to that VC issue?
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post #98 of 482
2/12/13 at 12:12pm
Quote:
Originally Posted by Ricci View Post

Interesting story is that I now possess the pair of drivers that Vance tested.

Data-Bass-ification soon?
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post #99 of 482
2/12/13 at 1:17pm
Quote:
Originally Posted by coctostan View Post

HTDoc - short of a Truextent beryllium in a JBL or Radian 95x, or a TAD 4003 I'm not sure you can find a better driver for the 1.4,1.5 or 2" horns. It is definitely the best value with this group buy. The only downside is the need to design a crossover.

I've already got the JBL covered as well smile.gif I already have JBL 2446 2" with beryllium replacement diaphragms and 2447 1.5" with beryllium replacement diaphragms waiting on said horns to arrive... I was going to just play with those... but if I'm going to do it, might as well explore the options out there smile.gif I'd like to try TAD as well, but I'll have to satisfy myself with my poor man's TAD with the replacement diaphragms in the JBLs... I don't trust some of the used TADs I've seen pop up and new TAD units are a bit beyond what I want to spend to essentially experiment and satisfy my curiosity about big horns and high efficiency speakers for two channel music listening....

My goal is to keep at least one or two variables constant and work around that to build a few different speaker options for full range 2 channel music listening only. In this instance it will be the woofers (AE TD15M and TD15H) with swappable horn and CD tops (building the woofer box so I can bolt JBL 2509a mounts to the top of the box in a couple spots to get consistent Z offset no matter which horn is mounted)... crossovers will be external passive boxes to allow easy tweaking.... and I'm going to explore active with a Trinnov Amethyst preamp if I can get my hands on one... I've got half a dozen different all tube, tube hybrid, or SS amp and DAC options as well to try for the best combination of equipment... it should be interesting and fun to try out... I'm one of those snake oil guys that believes he hears all the things that others say don't exist like differences in cables and differences in teh sound of amps, DACs, etc...... so my subjective findings won't really merit much discussion on here once things are built...

I haven't really designed my own crossovers in years... I think the last time I built my own speakers, I was using Leap for the crossover sims.... not sure if it will run on windows 7 boxes... so I may have to play with some modern software. I've got 4 or 5 measurement systems here... so I should be able to measure some stuff and get accurate results... we'll see smile.gif
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post #100 of 482
2/12/13 at 2:47pm
Thread Starter 
Quote:
Originally Posted by hometheaterdoc View Post

Tried to call in my order yesterday. Got voice mail.... will try again today. I was thinking of getting waaaaay too much stuff to play with.... then did a reality check as to what was humanly possible over the next couple years given my extremely tight schedule and lack of free time. So just going to get one pair of 4592 2" exit coaxial CDs for the iwata-300 horns on order and one pair of 4595 1.5" exit coaxial CDs to try on SEOS-24s on order. So I'm contributing $2886 MSRP to the $10K minimum to hit the discounted price...

NIce!! My msrp on the order is just over $6700, so between us, the minimum is all but met!! Jack is in and out, but if you leave him a message, he usually returns a quick call...I just try him again in a bit when I can't get him/

Quote:
Originally Posted by coctostan View Post

JTR uses the 4593 in the Noesis (I'm about 95% certain based on a pic). It could be due to cost considerations but I doubt there would be much savings and if it was significantly inferior I doubt he would use it. How much cheaper is it? The 4594 looks better on paper to me.

HTDoc - short of a Truextent beryllium in a JBL or Radian 95x, or a TAD 4003 I'm not sure you can find a better driver for the 1.4,1.5 or 2" horns. It is definitely the best value with this group buy. The only downside is the need to design a crossover.

Ricci- Do you have a link to that VC issue?

The 93 is like $50 less, so not a whole lot of difference. I can't wait to see the builds that pop with all the new BMS gear people will have.
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post #101 of 482
2/12/13 at 4:19pm
Quote:
Originally Posted by ChopShop1 View Post

NIce!! My msrp on the order is just over $6700, so between us, the minimum is all but met!! Jack is in and out, but if you leave him a message, he usually returns a quick call...I just try him again in a bit when I can't get him/

It was my fault.... I fat fingered one of the digits in the phone number and was hitting redial instead of re-punching the numbers... interestingly enough, the voice mail said "Hi, You've reached Jack at *garbled*......" so I didn't think anything of it.... until I called again this afternoon and he actually answered and told me I had the wrong number smile.gif *facepalm*

I'll get the order in tomorrow...
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post #102 of 482
2/12/13 at 4:19pm
Quote:
Originally Posted by hometheaterdoc View Post

I've already got the JBL covered as well smile.gif I already have JBL 2446 2" with beryllium replacement diaphragms and 2447 1.5" with beryllium replacement diaphragms waiting on said horns to arrive... I was going to just play with those... but if I'm going to do it, might as well explore the options out there smile.gif I'd like to try TAD as well, but I'll have to satisfy myself with my poor man's TAD with the replacement diaphragms in the JBLs... I don't trust some of the used TADs I've seen pop up and new TAD units are a bit beyond what I want to spend to essentially experiment and satisfy my curiosity about big horns and high efficiency speakers for two channel music listening....

My goal is to keep at least one or two variables constant and work around that to build a few different speaker options for full range 2 channel music listening only. In this instance it will be the woofers (AE TD15M and TD15H) with swappable horn and CD tops (building the woofer box so I can bolt JBL 2509a mounts to the top of the box in a couple spots to get consistent Z offset no matter which horn is mounted)... crossovers will be external passive boxes to allow easy tweaking.... and I'm going to explore active with a Trinnov Amethyst preamp if I can get my hands on one... I've got half a dozen different all tube, tube hybrid, or SS amp and DAC options as well to try for the best combination of equipment... it should be interesting and fun to try out... I'm one of those snake oil guys that believes he hears all the things that others say don't exist like differences in cables and differences in teh sound of amps, DACs, etc...... so my subjective findings won't really merit much discussion on here once things are built...

I haven't really designed my own crossovers in years... I think the last time I built my own speakers, I was using Leap for the crossover sims.... not sure if it will run on windows 7 boxes... so I may have to play with some modern software. I've got 4 or 5 measurement systems here... so I should be able to measure some stuff and get accurate results... we'll see smile.gif

Well it looks like you've covered your bases. I'm not sure the older TADs have anything over the JBLs with Truextents. The newer TADs (2002 and 4003) have some interesting phase plug designs that I would love to try but they are just too much. I've thought about grabbing some 2001s but have resisted.

I'll be very interested to hear your impressions of the differences between the Truextents JBLs and the BMS'S coax's. the BMSs might actually be better.

When you get measurements you should definitely post them as impulse responses and we can help with the crossovers. Modern software is pretty slick.
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post #103 of 482
2/12/13 at 6:28pm
Thread Starter 
Quote:
Originally Posted by bass addict View Post

This would be the most Epic group buy combo of all time. biggrin.gif

Ok, you asked...you got! Group buy details for AE can be found in the thread labeled AE group buy 2013 smile.gif
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post #104 of 482
2/12/13 at 6:51pm
Thread Starter 
In light of the new AE group buy, and its timeline, I think we will adjust the time frame on the BMS buy as well. John has agreed to run the AE buy until March 8th and it makes sense to run the BMS thread to the same timeline, so everyone has a bit more time to get some things worked out and jump on the BMS buy.
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post #105 of 482
2/12/13 at 6:57pm
john needs to finish the group buy from last year before starting a new one
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post #106 of 482
2/12/13 at 9:42pm
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Quote:
Originally Posted by cookieattk View Post

john needs to finish the group buy from last year before starting a new one

Replied in the AE thread in order to keep the BMS thread on BMS:)
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post #107 of 482
2/13/13 at 6:23am
Coctostan I still get paper VC copies instead of digital. Sry. I keep forgetting to switch.
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post #108 of 482
2/13/13 at 6:43am
Coctostan, I don't know if I'm allowed to direct link to the VC-magazine, but Google will help you find it in PDF for free.
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post #109 of 482
2/13/13 at 7:31am
I just subscribed for free online. I never knew it was free for the digital copy. I'm not sure I will have access to back issues though.
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post #110 of 482
2/13/13 at 12:56pm
Quote:
Originally Posted by tsloms View Post

I see that on their website they show a 4593ND and a 4594ND. The specs for them are nearly identical.

Does anyone know what the difference is and which one is better?

The difference is in the magnet for the HF section. On the 4594 it is a ring that is outside the VC (Voice Coil), on the 4593 it is inside the VC. (Not sure if it is a ring or round slug.)
The 4594 has a slightly better Flux Density. I have been told that the HF holds a bit stronger than than the 4593, but have not compared them.

Regards, Jack Arnott
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post #111 of 482
2/13/13 at 1:09pm
Quote:
Originally Posted by Aaron Smith View Post

I have one 4592ND 16-ohm coax compression driver...I was thinking it might be getting lonely and need a mate. Also have a couple of 4590 8-ohm ferrite monster coax drivers and was curious what the price would be...they're not on the list; although the 16-ohm versions made the list (great price as well). Another conspicuously absent piece is the 8-ohm 4550... confused.gif ...16-ohm is on there. The 4550 is a nice driver (proud owner of 5 of those...one per Yorkville U15 Unity...own of them brand-new as one of my Unitys arrived with a dead CD). I hear Erich's Denovo DNA-360 will give the 4550 a run for it's money though and it's quite a bit cheaper (even after the 30% discount).

I wonder if the list isn't quite complete? Just looked up the passive crossovers for the coax drivers and all that's listed is the 16-ohm.

Hello Aaron,
The price list is generated from a Quickbooks estimate, so only the16 ohm versions are listed for brevity.
The price for 8 ohm and 16 ohm is the same.

I also can order mixed impedances for cone/compression driver coaxials or triaxials.
I am using the 15" triaxial with 8 ohm cone, and 16/16 mid/hi.

It is the opinion of some from the factory that the 16 ohm models (compression drivers) sound better than the 8, but they can find no scientific reason for this.
I personally use 16, as they are easier to match up, sensitivity wise than the 8 ohm. And if you are doing a passive crossover you will need less padding to make a match with your woofers.

Regards, Jack Arnott
Assistance Audio
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post #112 of 482
2/13/13 at 1:15pm
Quote:
Originally Posted by coctostan View Post

That might work. They only have 8mm of xmax though. The 18N862's have 18mm I think. You could probably get down to a realistic 20hz with the right tuning in room and not worry about overexcursion. The 18N862's was more of an ultimate solution. I haven't used these myself and I've not even come across many builds that use BMS woofers. I can only go off of website specs and curves. The 18N862 might not play high enough. The curve looks good to 500hz, but spec sheet says 200hz max. Spec sheets aren't really worth all that much. You can't put much weight into them and BMS's are thin.

The reason the 18" woofers are rated to 200hz is because of directivity.
It is BMS's thought that the 18s are too directional above 200hz to be used with a wide pattern horn.
This is also the reason that the 15s are rated to 350hz.

This is not unique to BMS. (As in, any 18" speaker will exhibit the same directional characteristics.) I am not sure whether this is due only to the circumference of the speaker, or if the depth of it plays in also.

Regards, Jack Arnott
Assistance Audio
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post #113 of 482
2/13/13 at 2:18pm
Quote:
Originally Posted by tuxedocivic View Post

I just took a look at the product page for the 4550 and BMS says it's good for a 800hz cross over. That's SEOS15 territory, but the response graph falls like a brick below 800hz. Not sure how easy it would be to cross down there. I find the DNA-360 a pretty capable CD. I cross the DNA-350 at 950hz in my personal speaker, and it's not a problem. What does the 4550 offer over the DE250 or DNA-360?

I think the reason for the drop below 800hz on the product page is due to the horn, not the driver. I have used these drivers to 800hz with good results.
I have some customers who have used them lower, but I know they may not meet power or distortion specs below this point.
This is also the case with the 4552. It is rated to 1Kz, not 800hz, even though they both have the same VC (voice coil) and membrane. The reason is that the 4552 is a smaller driver (neo vs. ceramic magnets) and the 4552 opens up faster to get to the 1" throat size.
So it has more distortion below 1Khz.

In answer to your last question. All BMS drivers are a ring radiator diaphragm design, the B&C is a full dome diaphragm.
As such, the VC on the BMS only has to control a very small length of diaphragm at any one point.
It also gives less room on the BMS diaphragm for break up, or standing modes. Also, since the VC is in the center of the diaphragm, and not ringing the outside, even though they both have 1.75" VCs, the BMS will have more diaphragm surface area.

So you will get better transient response, less over ring, and higher sensitivity from the BMS.

In my opinion, generally speaking, the B&C drivers will have a flatter frequency response, the BMS will have better dynamics, and a more detailed and smoother sound.

Regards, Jack Arnott
Assistance Audio
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post #114 of 482
2/14/13 at 10:16am
Jack Arnott

Thread Killer
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post #115 of 482
2/14/13 at 10:35am
Quote:
Originally Posted by Jack Arnott View Post

Jack Arnott

Thread Killer

HAHA!!!! It's just a ton of extremely useful info that we are trying to soak in. Thanks a lot!
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post #116 of 482
2/14/13 at 10:47am
Quote:
Originally Posted by Jack Arnott View Post

Jack Arnott

Thread Killer

Oh man, I didn't even see these posts yesterday. That's hilarious. The NA BMS rep comes into this thread and dumps a pile of info in here and gets crickets for an audience.

Thanks for the useful info Jack. Wish I could buy some tasty parts from the group buy, but not this time around for me. The 4550 sounds like a great CD if it can be pushed down into the 800hz range. If a SEOS 18 was used an an 800hz cross over to a 15" woofer. I think it would be world class sound and 98% of what the coax CDs can offer.
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post #117 of 482
2/14/13 at 11:08am
Thread Starter 
Quote:
Originally Posted by Jack Arnott View Post

Jack Arnott

Thread Killer

Absolutely priceless!!

Thanks for getting the info in here Jack, I could not remember exactly what you had told me. I am actually surprised that more people haven't already responded to you with more questions.
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post #118 of 482
2/14/13 at 11:40am
"Wish I could buy some tasty parts from the group buy, but not this time around for me. The 4550 sounds like a great CD if it can be pushed down into the 800hz range. If a SEOS 18 was used an an 800hz cross over to a 15" woofer. I think it would be world class sound and 98% of what the coax CDs can offer."



Don't forget about the BA750. Here's bwaslo's measurement of the BA/SEOS18 combination. Looks like the the BA will extend down to 650hz or so.

http://www.diysoundgroup.com/forum/index.php?topic=31.0

Edited by rajacat - 2/14/13 at 11:54am
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post #119 of 482
2/17/13 at 4:02am
Chopshop where do I find a price list for the group buy?
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post #120 of 482
2/17/13 at 6:12am
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Quote:
Originally Posted by chrapladm View Post

Chopshop where do I find a price list for the group buy?

Just pm me your email and I will get the details over to you asap.
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