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post #151 of 188 Old 03-01-2017, 07:32 AM
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Those are nice looking cabs. Where were these a year ago!? I wouldn't have had to design / build my own vented cabs for DB testing.
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post #152 of 188 Old 03-01-2017, 07:44 AM
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Originally Posted by eng-399 View Post
Very nice Mark have you tried adding the flare to the back end of port inside the box would that help at all. The boxes look really nice great work. I talked to Bennett on the phone a few days ago about the B&C 21DS115-4 he's a really nice guy and knows these drivers.
If you want to make the box another 3-4" deeper on an already massive 32" depth, or custom cut more sections of the 12" sections Precision Port sells, yes, it would work well. Pressures are higher inside the box and noises are less audible. There is a 1/2" radius on the internal end where the port recesses cleanly into the flat brace, so it's definitely not a sharp termination. Terminating the port on a flat surface also has a significant and desirable effect. In this case we were able to obtain a longer pipe allowing no length cutting and a nice length for tuning that could be built-to-order efficiently and consistently.

If the port length was the same with the same flare in front at the rear I would expect the differences to be mostly observed at the levels where the port starts to limit along with possibly a slight lowering of port tune related to effects at the exit.
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post #153 of 188 Old 03-01-2017, 07:52 AM
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Nice cab, but wow, almost $800 in raw mdf.
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post #154 of 188 Old 03-01-2017, 10:38 AM
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Quote:
Originally Posted by Ricci View Post
Those are nice looking cabs. Where were these a year ago!? I wouldn't have had to design / build my own vented cabs for DB testing.
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Originally Posted by notnyt View Post
Nice cab, but wow, almost $800 in raw mdf.
Indeed. They definitely aren't cheap, but I would suspect that most who have built large a cabinet understand the adventure of assembling and handling large panels and enclosures. I would argue that receiving a professionally assembled enclosure with precision lock miters and zero end grain to deal with, or having a living room ready finish out of the box represents some tangible value. Obviously there's a lot of CNC time and labor going into the cabinets, not to mention the materials to safely pack the subs on a pallet. I believe the raw materials list was approaching $300. 3 sheets through the CNC, after CNC prep, assembly, and packaging all add up if a company needs to retain a profit and keep things available long term. Also remember that many of the small companies serving this hobby never properly evaluate their real costs and don't charge nearly enough to have a sustainable offering. Most 21" woofers on the market also aren't priced at HT18 prices either. Even the B&C woofers we are discussing in this thread are great performers, but in no way cheap.

For those who are skilled builders with tools and space to handle a large box and even enjoy that part of the process, I expect they will roll their own or find a flat kit and save the cost in trade for time, space, and lots of clamps. For those who want to select the driver used, use a powerful pro amplifier, or want something different from what they see in the market and are comfortable loading and wiring up a big woofer, this should make for a unique offering. As compared to a turnkey product, it's also a lot easier to carry the empty cabinet into a basement or up a flight of stairs before you load in the woofer.

With the info I have an will continue to share, plenty of DIYers rolling their own can benefit from the info and adjust for their own goals and needs. In the coming months I'm hopeful to get a cabinet to Josh Ricci to play with and test.
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post #155 of 188 Old 03-01-2017, 10:48 AM
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Originally Posted by Mark Seaton View Post
Indeed. They definitely aren't cheap, but I would suspect that most who have built large a cabinet understand the adventure of assembling and handling large panels and enclosures. I would argue that receiving a professionally assembled enclosure with precision lock miters and zero end grain to deal with, or having a living room ready finish out of the box represents some tangible value. Obviously there's a lot of CNC time and labor going into the cabinets, not to mention the materials to safely pack the subs on a pallet. I believe the raw materials list was approaching $300. 3 sheets through the CNC, after CNC prep, assembly, and packaging all add up if a company needs to retain a profit and keep things available long term. Also remember that many of the small companies serving this hobby never properly evaluate their real costs and don't charge nearly enough to have a sustainable offering. Most 21" woofers on the market also aren't priced at HT18 prices either. Even the B&C woofers we are discussing in this thread are great performers, but in no way cheap.

For those who are skilled builders with tools and space to handle a large box and even enjoy that part of the process, I expect they will roll their own or find a flat kit and save the cost in trade for time, space, and lots of clamps. For those who want to select the driver used, use a powerful pro amplifier, or want something different from what they see in the market and are comfortable loading and wiring up a big woofer, this should make for a unique offering. As compared to a turnkey product, it's also a lot easier to carry the empty cabinet into a basement or up a flight of stairs before you load in the woofer.

With the info I have an will continue to share, plenty of DIYers rolling their own can benefit from the info and adjust for their own goals and needs. In the coming months I'm hopeful to get a cabinet to Josh Ricci to play with and test.
I can see raw materials approaching $300 for one of the finished cabs, but for the raw MDF cab, that seems really high. It's a good offering though, and will likely serve as a good option for people who can't build their own. The B&C woofers aren't cheap, but they're still cheaper than the raw cab in this case.
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post #156 of 188 Old 03-04-2017, 06:41 PM
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post #157 of 188 Old 03-09-2017, 10:33 AM
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Quote:
Originally Posted by Mark Seaton View Post
I designed this cabinet for another company and it gave me a reason to do some testing on these rather interesting drivers and some big ported enclosures. It's always gratifying when the end result tunes and measures very close to what was simulated and estimated, and I found and confirmed a few interesting behaviors with the ports I had suspected based on very different port implementations. The cabinets have been available direct from my cabinet shop for about a week, and I just added some info on my forum. Bennett was generous in helping us get the drivers to physically verify and test in the cabinet.

I'll post up an impedance curve of the 21IPAL I have still loaded in the test box. To head off the "pictures or it didn't happen..." here are some pictures of the lock-mitered (no end grain to deal with) bare MDF cabinet, the black maple cabinet loaded with a one of the B&C drivers, and a white cabinet with the black grill (there are magnets installed behind the face for the grill frame):





I think these just got a shout out on audioxpress. Its in their audio voice #122 email. Thumbs up

Ryan
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post #158 of 188 Old 03-09-2017, 01:37 PM
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Originally Posted by eng-399 View Post
Mark what do you suggest for break in time for these B&C subs. Do you you run any specific material for that. I'm waiting on four of the B&C 21DS115-4 to arrive at my house.
Thanks
Sorry for missing this. A sine wave no lower than 20Hz in free air is easiest to generate the excursion to break it in. Don't do it in box else you can possibly burn things. In free air the impedance is 10-15 Ohms at 20Hz due to the impedance peak, meaning you can't heat it up too easily. Run it to 3/4 or more of the maximum travel, just before you hear a distortion increase from the suspension. 5 minutes probably gets you to 80% break in, and 15-20 mins more than 90-95%. Taking an impedance curve would show the Fs of the driver shifting a little lower after the burn in.
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post #159 of 188 Old 03-09-2017, 01:42 PM
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Sorry for missing this. A sine wave no lower than 20Hz in free air is easiest to generate the excursion to break it in. Don't do it in box else you can possibly burn things. In free air the impedance is 10-15 Ohms at 20Hz due to the impedance peak, meaning you can't heat it up too easily. Run it to 3/4 or more of the maximum travel, just before you hear a distortion increase from the suspension. 5 minutes probably gets you to 80% break in, and 15-20 mins more than 90-95%. Taking an impedance curve would show the Fs of the driver shifting a little lower after the burn in.


Thanks Mark! I'll do just as your saying I have a letter to tell how many ohms there at to from what your saying. I can't believe how big these drivers are in person! There huge it should bring some fun into the theater room.
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post #160 of 188 Old 03-09-2017, 01:43 PM
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I think these just got a shout out on audioxpress. Its in their audio voice #122 email. Thumbs up
Thanks tux'! Obviously I didn't write it, but here's the link to the piece you are referring to at AudioXpress. If a few more decide to dive into a DIY sub at this end of the performance scale by making a nice enclosure available to arrive at your home in 2-3 weeks of ordering, that's good for everyone. There's a related pro audio sub cabinet coming next that's 10" shallower with a ~28Hz tuning.

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post #161 of 188 Old 03-10-2017, 09:31 AM
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I can see raw materials approaching $300 for one of the finished cabs, but for the raw MDF cab, that seems really high. It's a good offering though, and will likely serve as a good option for people who can't build their own. The B&C woofers aren't cheap, but they're still cheaper than the raw cab in this case.
Just to clarify, the X21 subwoofer cabinet is not a set of unassembled machined MDF parts. The X21 is fully assembled lcok-mitered (a two-man build operation due to the size of the parts) and finished (excluding MDF cabinets) and includes all port tubes, recesses specific to each subwoofer, installed tee-nuts specific to each subwoofer and the specified terminal cup and all machine screws needed to install the specified components. This is a “load and play” subwoofer cabinet professionally engineered by Mark Seaton, prototyped, CNC machined, tested and verified. Test data for each supported subwoofer is provided so that the DIY community can select the driver they want (currently 6 different choices with more to follow) and make decisions based upon known performance data and their individual budgets. This product offering is intended to respond to members of the DIY community who don’t have the time, knowledge and tools to design and or build their own 21” subwoofers or the interest in purchasing commercially available offerings.

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WW Speaker Cabinets division of WW Displays, Inc.
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post #162 of 188 Old 03-10-2017, 09:34 AM
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Originally Posted by Robert F Miller View Post
Just to clarify, the X21 subwoofer cabinet is not a set of unassembled machined MDF parts. The X21 is fully assembled lcok-mitered (a two-man build operation due to the size of the parts) and finished (excluding MDF cabinets) and includes all port tubes, recesses specific to each subwoofer, installed tee-nuts specific to each subwoofer and the specified terminal cup and all machine screws needed to install the specified components. This is a “load and play” subwoofer cabinet professionally engineered by Mark Seaton, prototyped, CNC machined, tested and verified. Test data for each supported subwoofer is provided so that the DIY community can select the driver they want (currently 6 different choices with more to follow) and make decisions based upon known performance data and their individual budgets. This product offering is intended to respond to members of the DIY community who don’t have the time, knowledge and tools to design and or build their own 21” subwoofers or the interest in purchasing commercially available offerings.

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*shrug* The price for the raw cab is still high.
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post #163 of 188 Old 03-15-2017, 11:24 AM
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Thanks for the measurements Mark. Looks just as expected for those drivers in that cab.
+1 on the above. After adding the typical low pass and a high pass that's going to go quite a ways towards flattening the response out especially if those are carefully selected to help do just that. A gradual roll off down towards 20Hz isn't necessarily bad either depending on the room they will be used in.
Hi Josh,

I happened to get around to exporting some measurements to create some recommended filter settings. While this might be a bit flatter than I would probably dial in for the tastes of many here and most rooms, here's an example of what can easily happen with 3 filters. I used a MiniDSP 2x4HD as an easy example, but the filters are in most DSP using:

1. L-R 2nd order high pass at 20Hz (=2nd order Q=0.5 filter)
2. A 2nd order High Shelf at 100Hz cutting 14.5dB
3. A single parametric filter at 26Hz with a Q of 1.0 and +5dB of gain

This response is +/-3dB from 17-120Hz, and should be useful to 16Hz in-room:
Please note the 35Hz & 53Hz bumps are environmental and not characteristic of the sub or drivers.



Here is the overlay of the raw measurement vs post filtering:



In moderate size rooms I might suggest reducing the cut on the high shelf by 2-3dB and adjusting the frequency to yield a flat plateau above 50Hz a few dB higher. If your DSP allows filtering below 20Hz you can easily push the high pass down toward 15Hz. This change in the high pass mostly changes the shape of the low corner and only pushes that -3dB corner down about 1/2Hz to 16.5Hz which looks like this:

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post #164 of 188 Old 03-15-2017, 11:35 AM
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Following up with the same filtering applied to the B&C 21DS115-4 measurements:

20Hz 2nd order LR High Pass:


15Hz 2nd order LR High Pass:
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post #165 of 188 Old 03-20-2017, 08:49 AM
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Nice!

Thought I would chime in with a quick peak of the initial sweeps of the 21DS115-8 in my tapped horn, with a shout out to Lilmike for the help with the design and getting my REW & Windows settings straightened out. Sweeps were taken at the horn mouth, which I'd swung around so it was in the middle of the room as far from reflective surfaces as possible. I did not measure the voltage input, but plan to do sweeps with a known voltage soon.

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post #166 of 188 Old 04-17-2017, 05:42 AM
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New 18DS115 emerged. That´s something! That´s closer to the IPAL approach, with very manageable impedance and quite high Re. That looks great. How about 15" and 12" versions? That would knock some socks off....
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post #167 of 188 Old 04-17-2017, 08:35 AM
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Quote:
Originally Posted by notnyt View Post
Nice cab, but wow, almost $800 in raw mdf.
Quote:
Originally Posted by notnyt View Post
I can see raw materials approaching $300 for one of the finished cabs, but for the raw MDF cab, that seems really high. It's a good offering though, and will likely serve as a good option for people who can't build their own. The B&C woofers aren't cheap, but they're still cheaper than the raw cab in this case.
Quote:
Originally Posted by notnyt View Post
*shrug* The price for the raw cab is still high.
Quote:
Originally Posted by Mark Seaton View Post
Indeed. They definitely aren't cheap, but I would suspect that most who have built large a cabinet understand the adventure of assembling and handling large panels and enclosures. I would argue that receiving a professionally assembled enclosure with precision lock miters and zero end grain to deal with, or having a living room ready finish out of the box represents some tangible value. Obviously there's a lot of CNC time and labor going into the cabinets, not to mention the materials to safely pack the subs on a pallet. I believe the raw materials list was approaching $300. 3 sheets through the CNC, after CNC prep, assembly, and packaging all add up if a company needs to retain a profit and keep things available long term. Also remember that many of the small companies serving this hobby never properly evaluate their real costs and don't charge nearly enough to have a sustainable offering. Most 21" woofers on the market also aren't priced at HT18 prices either. Even the B&C woofers we are discussing in this thread are great performers, but in no way cheap.

For those who are skilled builders with tools and space to handle a large box and even enjoy that part of the process, I expect they will roll their own or find a flat kit and save the cost in trade for time, space, and lots of clamps. For those who want to select the driver used, use a powerful pro amplifier, or want something different from what they see in the market and are comfortable loading and wiring up a big woofer, this should make for a unique offering. As compared to a turnkey product, it's also a lot easier to carry the empty cabinet into a basement or up a flight of stairs before you load in the woofer.

With the info I have an will continue to share, plenty of DIYers rolling their own can benefit from the info and adjust for their own goals and needs. In the coming months I'm hopeful to get a cabinet to Josh Ricci to play with and test.

Mark answered your question. Let it go. If you don't want to pay it then move on. I can think of a lot of people that would rather go this route then either purchase a high end sub with possibly less performance.

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post #168 of 188 Old 04-17-2017, 09:58 AM
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Mark answered your question. Let it go. If you don't want to pay it then move on. I can think of a lot of people that would rather go this route then either purchase a high end sub with possibly less performance.
You realize you just responded to posts that were a month and a half old right? Maybe you should let it go. I wonder what the market will have to say. I haven't heard of anyone buying these yet. I wonder how many have sold.

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post #169 of 188 Old 04-17-2017, 10:37 AM
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b&c new audiophile speakers

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Originally Posted by Petr Berka View Post
New 18DS115 emerged. That´s something! That´s closer to the IPAL approach, with very manageable impedance and quite high Re. That looks great. How about 15" and 12" versions? That would knock some socks off....


Very nice the B&C 18DS115! Do you have any pictures of it or specs. Hopefully you guys can make the 15" and 12" DS version as well. I really like my 21DS115-4's!

Edit: found the specs on the B&C site of the 18

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post #170 of 188 Old 04-17-2017, 12:34 PM
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Out of curiosity would anyone seriously be interested in a group buy of 21 Ipal drivers with a 4ohm impedance? The requirements would be 50 total drivers needed to get it done with a higher impedance. Assume that the driver parameters and performance are the same other than the impedance (might be different slightly but not majorly so.). No changing of soft parts for lower Fs or other custom requests. I know a few people that would be in but that is a lot of drivers and they are expensive even if there was some sort of discount and I do not know that there would be. It would not happen without a serious commitment. I could use 4 myself possibly 8 total but never considered it a real possibility. I'm just trying to get a gauge on any interest in it if any.
I guess that depends if it's much of an upgrade for the Othorns, then I'd possibly be interested in two.

Though I've had my eye out on the 1 ohm (current) model drivers, but so far the current cost I see online just makes it hard for me to justify. So far my current B&C 21s do quite well, I just need bigger amps.


Though the idea is rather intriguing, because that would allow for it to be easier to use most amps on the market, say bridged amps.
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post #171 of 188 Old 04-18-2017, 04:45 PM
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New 18DS115 emerged. That´s something! That´s closer to the IPAL approach, with very manageable impedance and quite high Re. That looks great. How about 15" and 12" versions? That would knock some socks off....
Hey All,

The 18DS115 is basically (but not exactly) the same coil used on the 21DS115 - a 4.5" four layer CCAW coil. Twice the windings in the gap means a very high Bl versus the standard motor, but the aluminum helps to keep Mms reasonable. Since the only real change is the coil, price is the same as our 18SW115 or 21SW115 respectively. Le goes way up, but that doesn't mean so much in a subwoofer with its low frequencies and limited bandwidth. The suspension has been optimized a little more for the heaver Mms and for higher excursion, so for you guys trying to get super low this should be a great option.

A 12" version is unlikely since we don't have a 4.5" motor 12" anything. A 15" is possible, but let's see how the 18" works out first - really waiting on the market to tell us if this is preferred to the 18SW115 and if so in what applications.

We should have these in stock late summer.
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post #172 of 188 Old 04-18-2017, 04:49 PM
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Why would you want to use the 18 over the 21?
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post #173 of 188 Old 04-18-2017, 05:13 PM
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Hey All,

The 18DS115 is basically (but not exactly) the same coil used on the 21DS115 - a 4.5" four layer CCAW coil. Twice the windings in the gap means a very high Bl versus the standard motor, but the aluminum helps to keep Mms reasonable. Since the only real change is the coil, price is the same as our 18SW115 or 21SW115 respectively. Le goes way up, but that doesn't mean so much in a subwoofer with its low frequencies and limited bandwidth. The suspension has been optimized a little more for the heaver Mms and for higher excursion, so for you guys trying to get super low this should be a great option.

A 12" version is unlikely since we don't have a 4.5" motor 12" anything. A 15" is possible, but let's see how the 18" works out first - really waiting on the market to tell us if this is preferred to the 18SW115 and if so in what applications.

We should have these in stock late summer.
Why is xvar on the 18 lower than the 21 even though the 18 has the longer coil, suspension limits? Also, what's the xmech on the ds models?

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post #174 of 188 Old 04-18-2017, 07:47 PM
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Originally Posted by notnyt View Post
Why is xvar on the 18 lower than the 21 even though the 18 has the longer coil, suspension limits? Also, what's the xmech on the ds models?
Notnyt would the Xmech be further than the 30mm excursion before damage posting they stated?

I am only asking because I figured the suspension will stop the driver from moving even to that point but curious to know more about the BC figures also. I did also see the Xmax was 16.5mm and Xvar was less on the 18 as compared to the 21.
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post #175 of 188 Old 04-19-2017, 06:24 AM
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The Xvar is dependent upon all the other parameters. Probably the suspension is the limiting factor

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post #176 of 188 Old 04-19-2017, 08:35 AM
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If you look at the coil / gap geometries on the B&C woofs you'll see that the coil would leave the gap well before any parts make contact. That and the suspension compliance becoming very tight makes it pretty much impossible to hard bottom them. At least in my experience.
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post #177 of 188 Old 04-19-2017, 12:43 PM
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post #178 of 188 Old 04-19-2017, 01:02 PM
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Quote:
Originally Posted by chrapladm View Post
Notnyt would the Xmech be further than the 30mm excursion before damage posting they stated?

I am only asking because I figured the suspension will stop the driver from moving even to that point but curious to know more about the BC figures also. I did also see the Xmax was 16.5mm and Xvar was less on the 18 as compared to the 21.
where was 30mm xmech posted? If it was I missed that.

40mm coil in 14mm gap leaves gap at 27mm... i was just curious where the suspension limits were and where it becomes a clearance problem
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post #179 of 188 Old 04-20-2017, 06:51 AM
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Quote:
Originally Posted by radulescu_paul_mircea View Post
The Xvar is dependent upon all the other parameters. Probably the suspension is the limiting factor
Exactly.

Quote:
How does B&C calculate the Xmax (excursion) specification, and what is Xvar?
Evolution is a process that affects not only products, but also their technical specifications. Constant advances in research provide more and more precise methods to measure the performance of loudspeakers, and describe their features. Thiele – Small parameters have become the universal language for describing loudspeaker behavior in the small signal domain. Nevertheless, they comment little on the working limits of loudspeakers in the large signal regime.

These limits are customarily indicated by Xmax, the maximum linear excursion. This value is typically measured according to the AES2-1984 standard, corresponding to a maximum of 10% total harmonic distortion (THD) with a sinusoidal signal (though most manufacturers, including B&C, now typically provide data for Linear Mathematical Xmax, not measured Xmax). Recent research shows that this method can yield ambiguous results, and even different numerical values for the same loudspeaker. The main limit of this measurement is that it looks at the output signal instead of the physical features of the driver itself. On the contrary, the most up-to-date instruments for distortion analysis can measure the variations in loudspeaker parameters when they are fed with high-level signals. In this way, an excursion limit can be fixed, beyond which the parameter’s variation becomes excessive.

The “X var” value reported in our data (generally after the traditional “Xmax” value) is measured this way. Beyond this excursion limit, the magnetic field seen by the voice coil, or the total suspension compliance, or both, drops to less than 50% of their small signal value, producing high distortion levels, strong variations from small signal behavior and power compression. The new technique yields different results from the standard measurement based on THD. B&C Speakers believes that this added information gives a more accurate and reliable description on loudspeakers behavior in actual operating conditions.
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post #180 of 188 Old 04-21-2017, 01:38 PM
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Notnyt: because many of us strive for power density, not the largest box. Even when the full potential of the speaker wouldn't be used, it would be obvious that one gore-power equipped 18" in 100l box would do more than any other 15" in conventional and simulation suiting box of the same volume, or two of these 18s are easier to load into the car, instead of single 180-200l 21" box. Two coils, less heat for the same amount of power.

Sometimes I think about why is even B&C playing this big boy IPAL game, when it would be easier to use more pieces of smaller drivers with 4" voice coils. These just need higher excursion versions, adequate to what big boys do...

I don't even have my final 21DS115 box built(by pros) yet, and I'm lurking about how to make my system more loading/unloading friendly. More, more powerfull drivers is the way. But there are close to none. None of these goes over BL30, none of these goes 15+mm Xmax/Xvar. 15DS115 might get me into that territory.
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