The BMS group buy thread!!! - Page 7

Yup, you're right about that. I had it backwards. The 360 is only available if you buy it with the SEOS not the other way around.

LOL. Come on Mike, step on over to the dark side.

It's looking like I'm going to be out for this round of the group buy, but maybe if others are interested (and of course Jack) we can get another one going in April/May timeframe.

+1 here too. I am enjoying the TD12x's too much already, and I need to offload a LOT of stuff before I start compiling things to build out again...

The first sentence is right. But it is because of the exit angle. I'm guessing there is more suspension in the throat of the 4550, and it supports the diaphragm better, because it is not expanding as fast.
Now I have to watch what I say here. I want to say that the diaphragms in the 4550 and 4552 are the same. But when I have done that, someone has ordered the wrong diaphragms thinking they are interchangeable, they are not.
They have the same voice coil, membrane, and phase collecty thingy and plug. But the topology is somewhat different. Different casing, and most importantly, centering ring.
The 4545, 4547 use the same diaphragm as the 4550. edit, attention!!! 4550 is a typo, they use the same diaphragm as the 4552. (Sorry, in and out, shipping, etc.)

On to that. The differences between those three, other than mounting which has been mentioned.
The 4545, and 4547 have the neodymium inside the voice coil, instead of outside/surrounding the voice coil.
This, and the resulting smaller foot print materials, is the difference in price.

It seems like there was one more thing to say, but I clicked out to check something, and lost my last response by not switching tabs, but going to another page.
Edited by Jack Arnott - 2/27/13 at 4:44pm

+1 Ya, same here and unless there is another GB I'll have to pay a bit more for some coaxials this Spring. It's kinda goofy timing. With the Auto-Tech pallet shipping now and the AE GB happening all at the same time, I couldn't get a pair of jmlc's or tractrix in time to test early Spring anyway. I'll just have to live vicariously through all the builds threads...oh, wait I do have a build!

Yea looks like a lot of us "early adopters" all seem pretty darn happy with what we have now, so we can just sit back and watch these builds populate and smack ourselves for not waiting a few more months for this opportunity...I will still be smacking myself while in continued audio bliss though so it probably won't hurt too bad

Oh no! I have bad news. I suspected this earlier, but all I have in the office are older catalogs.
I found a newer one at the warehouse, and as I suspected, the flux density on the 4545 and 4547 is lower than stated on the web site.
It is 1.7 Tesla.

I think I see what you are looking at, but it is a misnomer. At the top of the page, while you are looking at the 4547, is a two bolt driver. It is a 4552.
This driver stays there, no matter which driver you look at, and changes when you look at a single point source, or a cone speaker.

So the 4547 is three bolt only.

Why would you consider a change, or what would you be hoping to gain? The only real difference on a SEOS-12 I see between the BMS 4550 and the B&C DE250 is that the 4550 extends higher. But the 360 also extends higher than the DE250. So it's a wash. And I believe all 3 use the same diaphragm material.

I sent Geddes a DNA-360 and he tested it. He was impressed. Even though he said the 360 did indeed extend higher, that's not really worth looking at because very few people can hear around 19khz......and virtually no one can tell the difference of a few decibels up that high. The DNA-360 tests better than the DE250. But I've said many times it's not going to ever be noticed by anyone but a computer microphone. So at some point we should stop looking at 1db differences and just enjoy the speakers we've built.

Audio is one of the rare industries where people actually want to pay more for something, just to do it.

A good example is with the Karma Series versus the Fusion Series, or the 350 versus the 360 compression driver. No one has ordered the Karma Series yet, but the 15" model is one heck of a speaker that measures great, and sounds incredible. I've told people that every time they ask, but they always go for the more expensive Fusion-12.......just to be safe. Yet the Karma-15 is only in the Karma Series based on price......not performance.

On the SEOS-12, the 350 and 360 are nearly identical when crossed over where most of these speakers are. Back when I got all of this stuff in, I had an equal number of both. The 350 was $20 cheaper. When people were getting their preordered SEOS-12, many were getting the CD at the same time. The 360 was ordered about 40 to 1 compared to the 350.

My friends....we must stop the madness.
Edited by Erich H - 2/28/13 at 5:18am

LOL.

That reminds me of the story of cars and houses. You ask someone how much they paid for their house and they lie they paid more. You ask them how much they paid for their car and they lie they paid less.

In the HT world, if it costs more it must be better right?

Not around these parts sir

I sent them an email earlier today asking when they would ship. I was hoping they would have shipped on Monday, but I don't think that happened.

Oh my, you are not paying attention. The diaphragm is completely different. That is the difference.

This is an interesting one to argue. The same argument goes on over high res, 96/24, and one bit SACD. Some say that, of course its impossible to tell the difference.
But, if you hear it, or experience it, you can't not hear it.

I probably can't hear much above 13khz. But I can tell the difference between the BMS 1.5" VC, and the 1.75" VC. So the questions I ask myself are, is there enough hf out of my range that I can pick up via skin? (one theory that I don't subscribe to), or is it that your ears hear it, but it is so masked, and down in amplitude that it's not noticeably there, but subconscious? Used to be my theory. Now I think that music is very complicated. We are not listening to sine waves. So, the speed with which the diaphragm changes directions is important. Even in sub frequencies. So, in mid range, the diaphragm that changes directions fast enough to reproduce 20khz, is going to sound better in the vocal range, when it needs to change directions and replicate complex signals.

There is that, in a good dose. But there is something even darker than that.
This is the concept of worth. With some things its easier to quantify. Like cumin vs. paprika. The marked is set by an algorythm of cost of raising, on to getting it to market.
But when you get into smoked Spanish paprika, then, it's noticeably different, but how much more?

When I go to the Rocky Mountain Audio Fest, I think half the time the vendors are just making up the prices. They are all over the place, and with no real life correlation to how the speakers sound.

Guitar players have a wide range of instruments to choose from. And the better the guitar player, the more discerning they are on the instrument they choose to play. But at some point, the cost of the guitar is going to reach a point of diminishing returns. And worth will be determined simply by who, if anybody, has enough money and desire to buy a certain instrument.

Noted golf instructor Harvey Penick had an interesting take on getting new clubs. He observed that when you got a new driver, you spent a lot of time hitting it, and concentrated more when you used that club. But eventually, it would become mundane, and the person hitting it would not get as much out of the club. The club didn't deteriorate, it just was not hit with the same care as before. So the thing to do was to go get a new driver.
He escaped this spiral by becoming a teacher, and not playing professionally anymore.

I know a guy who has the same PA he bought in 1976. It is an ugly, bad sounding, Jurassic PA. But to his way of thinking, he bought a PA, and now he will never need to buy another one. His whole life.
That is certainly not me. I am always looking to improve. Not necessarily get bigger. Right now the quest is for more compactness. Easier to set up. I am looking to improve my horns too. Always something to tweak.

I am not familiar with these, but I feel your pain. I sometimes sell old speakers on eBay. If they have those three magic initials, they will go through the roof. JBL. I have sold cones that I had for over 20 years. Beat to crap in untold bar gigs, complete with beer stains. They will sell for more than I paid for them used, two decades ago. And cannot convince the buyers to buy something brand new with a warrantee, with numerous improvements that I can list and demonstrate. "do you have more JBL?"

I am part of the problem, and solution.
In fact that is a paraphrase of Homer Simpson, "To alcohol, the cause of, and solution to all our problems!"

I mean they basically use the same material (made the post edit). That's what I was talking about in another reply. Of course I know they all use different diaphragms.

What I was asking is where does the forum member see a benefit in changing a current speaker design that uses a SEOS-12 and a DE250 or DNA-360?

The analogy of SACD and 96/24 isn't really the same here. I'm talking about hearing a response blip at 19khz between two products, or even two of the same products. So we might not be discussing the same thing.
Edited by Erich H - 2/28/13 at 6:30am

Jack
I noticed on the BMS site that they offer a nice looking 1" FG horn that apears to be very interesting. Could you explain a little about it? It is not on the price list. How does it work with the 4550 or 4552?
Thanks
Chris
Edited by countryWV - 2/28/13 at 7:07am

Which model number are you talking about?

The 2119 or any other model that would work well with 4550 or 4552.
Thanks
Chris

Jack, I see what you're talking about on the page header. However, when you scroll down the 4547nd page they clearly have a 4547ndv1 and a 4547ndv2, with drawings of each. Moot point for me......I want the 3-bolt, and I'm sure most around here would be better suited to the 4550 anyways. I might just pop for the 4552 to eliminate the "what-ifs" down the road

When you said that the flux density on the 4547 and the 4545 is lower than what BMS has listed, would this account for their higher recommended xo?

Oh my heck! There it is. And crap. Now I have one more thing to stock, and differentiate. I would still send one with the 3 hole and an adapter to get crossover made, and then get in stock the two hole, so it would mount directly.

I don't see how that would make the difference. (If it is, it is something beyond what I know about flux density.) I need to get to the bottom of this.

Hello Chris, the 2119 (and all the BMS horns) are very rudimentary, and were designed as something simple to mount the drivers to, in the 90's.
BMS really did not extend the line, or make any improvements in design, and moved away from horns.
It seems they think that most of their customers will make custom horns for their proprietary designs. Or purchase BMS to replace existing drivers, on existing horns.

That is one very cool thing about this project. The amount of attention and detail that has gone into the horn design.
You should all be appreciative of that.

My thought is that the there are four reasons to use a compression driver over a dome tweeter.

1) Higher sensitivity.
2) Lower IM distortion.
3) Through the use of horn design you can create different dispersion patterns.
4) Better dynamics, transient response.

Because of the reasons I listed earlier, (mostly about the ring radiator designed diaphragms (BMS) vs. full dome suspension diaphragms (All other drivers)), I think that the BMS offers better dynamics and transient response.

i think what erich was getting at was the diminishing returns of moving from one good compression driver (the de250 or dna360) to another one (such as a 4550) in an otherwise similar build.

I haven't said anything about dome tweeters versus compression drivers. Of course these all use CD's.
Edited by Erich H - 2/28/13 at 9:28pm

At twice the price, I'd have to agree it doesn't make sense to upgrade from the 360 to say the 4550; but with the BMS group buy, IMO, it's a no brainer.

isn't the 4552nd a little smoother than the 4550?

Hi Erich, how is it going?
I seem to have offended you somewhere along the line.
I'm sorry if this is the case.

This thread is about purchasing BMS drivers, and I am offering my opinions, and advice.
Is there something specifically that I have avoided, or misinterpreted that I can try and answer for you?

Regards, Jack