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post #181 of 446 Old 02-12-2020, 07:51 PM
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What does the Hornresp sim for this look like? Can someone share the export file here?

I want to see how it compares with other possible designs using those drivers. For example, here's the sim'd response of 4 135 liter damped T-QWT boxes using the same drivers, driven to Xmax (15mm) with about 29V per box.

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post #182 of 446 Old 02-12-2020, 08:17 PM - Thread Starter
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Quote:
Originally Posted by Brian Steele View Post
What does the Hornresp sim for this look like? Can someone share the export file here?

Here’s the input, so you can play with it.


On 1000w:


Not something thats being kept secret, lol. I have a feeling it will be on the Index shortly.
John is probably just waiting for my subjective opinion at this point.

Chris
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post #183 of 446 Old 02-12-2020, 08:53 PM
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Originally Posted by a77cj7 View Post
Here’s the input, so you can play with it.
That image doesn't capture the semi-inductance parameters for the drivers, which are probably going to impact the response at upper bass frequencies.

Also, the sim seems suggest that the design was modeled as an offset-driver vented chamber arrangement. Based on the layout of the actual build, the response at upper frequencies with probably be modeled more accurately if the sim done using the parallel 6th order BP option, as this approach would allow you to show the impact of the offset of the drivers in the rear section of the enclosure as well as the front section. The OD setting only allows simulating the impact of the offset in the front section - it assumes that the drivers are mounted on the panel that's facing the rear section's vent. Some quick fiddling with the sim suggests that it's this offset in the rear section that might explain the difference between sim and measured response between 100~200 Hz. Of course that's only academically useful - this subwoofer is likely not going to be used that high anyway

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post #184 of 446 Old 02-12-2020, 08:53 PM - Thread Starter
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EXPERIMENTAL Quad JBL Devastator Build

For those waiting for my listening impressions, sorry! I’ve got them up and running, but thats about it. My fiancé is sick and went to bed, so I’m not suicidal enough to turn it up.

First off, visual comparison:


Close mic sweep, equal power:

Well, that makes the quad look pretty nice.

At MLP, equal power:

Did I mention my room isn’t friendly?

I played some music at decent volumes. Yeah, both sound pretty bad, lol. The quad probably wins without eq, but the close-mic tells you that.

I’ll get them both eq’d and run through a bunch of demo material tomorrow. You’ll just have to wait another day.

Sorry this whole process has taken so long. Its almost been two weeks since I first agreed to build it.

Chris

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post #185 of 446 Old 02-12-2020, 09:04 PM - Thread Starter
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EXPERIMENTAL Quad JBL Devastator Build

Quote:
Originally Posted by Brian Steele View Post
That image doesn't capture the semi-inductance parameters for the drivers, which are probably going to impact the response at upper bass frequencies.



Also, the sim seems suggest that the design was modeled as an offset-driver vented chamber arrangement. Based on the layout of the actual build, the response at upper frequencies with probably be modeled more accurately if the sim done using the parallel 6th order BP option, as this approach would allow you to show the impact of the offset of the drivers in the rear section of the enclosure as well as the front section. The OD setting only allows simulating the impact of the offset in the front section - it assumes that the drivers are mounted on the panel that's facing the rear section's vent. Some quick fiddling with the sim suggests that it's this offset in the rear section that might explain the difference between sim and measured response between 100~200 Hz. Of course that's only academically useful - this subwoofer is likely not going to be used that high anyway


If you look way back on this thread, Josh, @Ricci , posted the semi-inductance data calculated using driver measurements by @Chris Popovich .

However, the JBL-spec model has been matching much closer than the semi-inductance one.

Josh also modeled the response in AkAbak, thats posted farther up as well.
EDIT: here it is:

Quote:
Originally Posted by Ricci View Post
Finally had a chance to fire up Akabak and run this cab real quick. No inductance modeling on this. It's like I suspected. Driver excursion behavior looks nasty unless all of the drivers are wired in parallel. There is still some uneven behavior with them in parallel but it looks much better. Anything involving series driver wiring appears to cause things to go awry at least according to Akabak.
Wish I had better news.


Teal is the HR type sim with the drivers sim'd at the midpoint between the physical locations.
Green and black curves are the FR with the driver pairs sim'd at their separate physical locations. Black is with parallel drivers and green with series/parallel



Josh has since figured out a wiring configuration that avoids the variable excursion issue. /EDIT



With the wicked resonance around 130hz, I don’t think this one is good for much over a 80hz 4th order LPF.
I plan to affix some pillows midway in the rear chamber to see if it helps with the resonance, I just haven’t gotten to it yet. So much testing, so little time.

Chris

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post #186 of 446 Old 02-12-2020, 09:08 PM
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Quote:
Originally Posted by a77cj7 View Post
[snip]......

First off, visual comparison:



Chris
Wow... great work man..... thank you for taking the reigns like this.....
I didn't realize just how big that box was..... makes the Mini look on the small side..... I had to go look at my Mini to get a better judge of it's size. So that box is basically 1/2 way between a Mini and an LFE in size.....


Those charts look promising.... hopefully it sounds good as well.....


Juju

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Quote:
Originally Posted by a77cj7 View Post
[snip]......
I plan to affix some pillows midway in the rear chamber to see if it helps with the resonance, I just haven’t gotten to it yet. So much testing, so little time.

Chris
I attached some poly batting about the size of a bed pillow and about 4" thick to the rear hatch of my LFE and it killed the ever so slight ringing at HIGH VOLUME [as in stupid loud] that it has. Hopefully, that will smooth out your tone as well.....


Juju

Sub List: 1- Red Five Mini V1 Devastator 18" w/PA460, 1- Red Five Devastator LFE 21", 1- Red Five Devastator 21" Finalizer V2 DF , 1- BOSS platform [The Hideaway Theater], 2- 18" "Full Marty" tuned to 17Hz w/RSS460HO
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post #188 of 446 Old 02-12-2020, 09:17 PM - Thread Starter
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Quote:
Originally Posted by jujuman200 View Post
Wow... great work man..... thank you for taking the reigns like this.....
I didn't realize just how big that box was..... makes the Mini look on the small side..... I had to go look at my Mini to get a better judge of it's size. So that box is basically 1/2 way between a Mini and an LFE in size.....
Juju

There’s a reason the mini is called “mini”.

It doesn’t help to visualize with yours, but the quad has almost identical enclosure displacement to the v1. Its just adjusted to be shallower and fatter to fit the 12” drivers side by side.

Chris
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post #189 of 446 Old 02-12-2020, 09:23 PM
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Quote:
Originally Posted by a77cj7 View Post
There’s a reason the mini is called “mini”.

It doesn’t help to visualize with yours, but the quad has almost identical enclosure displacement to the v1. Its just adjusted to be shallower and fatter to fit the 12” drivers side by side.

Chris
TRUE... but the Mini is still more than TWICE the size of NORMAL PEOPLES subs..... we on the other hand have a sickness . Lot's of people feel that a 12" sub is more than enough for movies.... US on the other hand, NEED better bass than our local cinema at the very least......


Juju
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post #190 of 446 Old 02-12-2020, 09:29 PM - Thread Starter
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TRUE... but the Mini is still more than TWICE the size of NORMAL PEOPLES subs..... we on the other hand have a sickness

Juju

Nah, most “normal people” have at most a undersized vented 12”. The mini is 8x the size.

Don’t mind me, I’m just assembling a 43 cubic foot subwoofer this weekend. To be one of six subs in my theater. Normal is boring.

Chris
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post #191 of 446 Old 02-12-2020, 09:36 PM
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Quote:
Originally Posted by a77cj7 View Post
Nah, most “normal people” have at most a undersized vented 12”. The mini is 8x the size.

Don’t mind me, I’m just assembling a 43 cubic foot subwoofer this weekend. To be one of six subs in my theater. Normal is boring.

Chris
I could not have said it better...... I just don't have the space for more.... but I have been debating should I swap out that 21" Marty for a second LFE 16Hz... can't just add the LFE. Something has to make room.....



Juju

Sub List: 1- Red Five Mini V1 Devastator 18" w/PA460, 1- Red Five Devastator LFE 21", 1- Red Five Devastator 21" Finalizer V2 DF , 1- BOSS platform [The Hideaway Theater], 2- 18" "Full Marty" tuned to 17Hz w/RSS460HO
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post #192 of 446 Old 02-13-2020, 05:42 AM
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I know there will be a ton of questions coming in as soon as the Quad gets up in the Index. Most of them I think are answered in here, but we might want to condense some important information, such as the wiring pattern for the woofers that beats the excursion issue. I am also curious if the pillow will take out some of the rear chamber ringing, that might get use up to a 100Hz cross over option vs the current 80Hz ceiling. Most folks run 80Hz so that might not be too much of an issue.



-John
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post #193 of 446 Old 02-13-2020, 06:35 AM
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Quote:
Originally Posted by a77cj7 View Post

Sorry this whole process has taken so long. Its almost been two weeks since I first agreed to build it.

Chris
Hey, don’t worrie about that. I don’t think anyone would have done it any faster, with a normal life on "the outside" of this to consider. I am in awe at how fast and how much you have done from this idea surfaced, very nice job indeed!

So cool that this actually turned out to work so good as it does, when the outsight didn’t look so positive

It is big, i repeat BIG, but i am not sure any sub at $120(+wood n’stuff) can match this. Any takers?

Completely different price level, but wonder how 4 x UM-12’s would perform, LOL?

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post #194 of 446 Old 02-13-2020, 08:11 AM
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@Nalleh I was also curious about the UM 12s but then I got REALLY curious about the CSS SDX 12. Definitely not a value option but I can’t help but see them in a mini MAUL configuration. They weigh 47.5 pounds each!
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@Nalleh I was also curious about the UM 12s but then I got REALLY curious about the CSS SDX 12. Definitely not a value option but I can’t help but see them in a mini MAUL configuration. They weigh 47.5 pounds each!

The response is really peaky, the sub has a high moving mass. The vent would need major re-tooling a much more capable sub than the JBL 12"s.
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EXPERIMENTAL Quad JBL Devastator Build

Quote:
Originally Posted by Nalleh View Post
Hey, don’t worrie about that. I don’t think anyone would have done it any faster, with a normal life on "the outside" of this to consider. I am in awe at how fast and how much you have done from this idea surfaced, very nice job indeed!



So cool that this actually turned out to work so good as it does, when the outsight didn’t look so positive



It is big, i repeat BIG, but i am not sure any sub at $120(+wood n’stuff) can match this. Any takers?



Completely different price level, but wonder how 4 x UM-12’s would perform, LOL?


There may have been some sarcasm involved, lol.

Yeah, it appears to hit the model nicely. I didn’t think it ever looked too bad, Josh was just predicting a 3db loss at high excursion, still very usable.
It seems that it was closer to 1db and has been avoided though.

I consider it in the same class as vbss, with two vbss to one of these.
Same nominal impedance and input power.
Vbss wins on less wood, easier build, easier to place two smaller boxes, and drivers are always available.
The quad wins on driver cost (during sale), cool factor, and “devastator sound” (i think, more on that today).

As John mentioned, high excursion drivers get very peaky in Devastator variants.

Chris
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post #198 of 446 Old 02-13-2020, 09:35 AM
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You guys made a budget beast for sure. Except I’ve been sitting over here patiently waiting..... you see I am interested in the half version of this, “The Dual” mostly for reasons of dimensions, I am hoping for a 14 inch wide version so I can build four for sure and maybe two more for the back without losing too much of my room. I also love the fact you could build four duals and power them with as little as a 3000d. I do know this is AVS and you all love EXCESSIVE but for us budget guys we would love to see something a little more user friendly and just build more of them, well I would anyways.

Nice job
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You guys made a budget beast for sure. Except I’ve been sitting over here patiently waiting..... you see I am interested in the half version of this, “The Dual” mostly for reasons of dimensions, I am hoping for a 14 inch wide version so I can build four for sure and maybe two more for the back without losing too much of my room. I also love the fact you could build four duals and power them with as little as a 3000d. I do know this is AVS and you all love EXCESSIVE but for us budget guys we would love to see something a little more user friendly and just build more of them, well I would anyways.

Nice job


As long as the drivers are parallel, I see no reason it won’t work.

Four duals should act just like two of these quads.
Your wood-to-driver cost will be higher, so it’s actually less budget-friendly.

Pretty sure you are still in the excessive range.

Chris
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post #200 of 446 Old 02-13-2020, 12:23 PM
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Your wood-to-driver cost will be higher, so it&#226;€&#x2122;&#xfe0f;s actually less budget-friendly.
Chris


You just have not figured it out yet have you??

When building - wood,time and products gets cut in half for every two you build.

Products are less money the more you buy and sometimes free when you have some laying around.

Wood is cheap for the return value in high efficiency low power subs. BOOM!!!!

Wood also gets easier to cut (less time changing dimensions on the table saw).

Multiples also have a better smoothing characteristic and the more you have the higher/better the low end Rolloff is too (I think).

Edit: and if they are all the same? BONUS.

I WIll build six or eight duals over just two LFEs any day of the week..... for the same price.

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You just have not figured it out yet have you??

When building - wood,time and products gets cut in half for every two you build.

Products are less money the more you buy and sometimes free when you have some laying around.

Wood is cheap for the return value in high efficiency low power subs. BOOM!!!!

Wood also gets easier to cut (less time changing dimensions on the table saw).

Multiples also have a better smoothing characteristic and the more you have the higher/better the low end Rolloff is too (I think).

I’ll build six or eight duals over just two LFEs any day of the week..... for the same price.



A box for that would ideally be 40x14.5x36. The JBLs would do best if they had about 200 liters of chamber space to play with. 600 watts with an 18Hz 3rd order filter keep excursion in check. Tune is about 18Hz as well.



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Nice (ongoing!) work, Chris! Your dedication and effort have been outstanding. Two things really strike me:


  1. How FAST you were able to construct this beast. I realize you have lots of building experience, but this is obviously far more complex than a simple Marty-type box.
  2. Your commitment to chasing data, going far beyond the call of duty to keep getting more measurements outdoors.
I will keep following along, especially for your subjective thoughts. I still am a bit mystified about the "devastator sound" that keeps being thrown around. You aren't a guy to get suckered into $1000 cables, but I do realize that there is more to sound than a simple frequency plot. I built a couple of mini-Martys a month or two ago, but haven't begun to dial in my theater as I also have dining room furniture taking up space as I have other projects ongoing (next comes wainscotting for the dining room). I have run this room in "wide mode" for years, but will likely redo the theater "long ways" [16 ' x 22', very open to lots of other space]. Deciding what further subs to build is part of that.


I guess I am curious as to how people with Dev experience rate this quad. Not just as a 'budget' build, but as a devastator PERIOD. How it sounds & performs relative to others with the usual drivers. I have seen some comparative graphs, but await further thoughts on this. IIRC you also said that this was an easier build in some ways.


Carry on, sir!
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post #203 of 446 Old 02-13-2020, 12:41 PM - Thread Starter
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Quote:
Originally Posted by Audiophile75 View Post
You just have not figured it out yet have you??

When building - wood,time and products gets cut in half for every two you build.

Products are less money the more you buy and sometimes free when you have some laying around.

Wood is cheap for the return value in high efficiency low power subs. BOOM!!!!

Wood also gets easier to cut (less time changing dimensions on the table saw).

Multiples also have a better smoothing characteristic and the more you have the higher/better the low end Rolloff is too (I think).

Edit: and if they are all the same? BONUS.

I WIll build six or eight duals over just two LFEs any day of the week..... for the same price.


The problem is going from the dual to the quad adds two additional side panels, the largest piece of wood in the build. You also double the number of front-to-back braces, but that is pretty minimal for cost.

Not sure how you figure cutting everything in half. I generally build two of each subwoofer. The only massive time savings is cutting panels for the second with a tablesaw. Assembly takes just as long. Wood can be slightly cheaper with proper cutlist optimization, but thats on a project-to-project basis.

Assembling two duals over one quad will take much longer.

The only reason I see to build twice as many duals instead of quads is, as you mentioned earlier, room fitment.
Since all of my enclosures are designed for specific fitments, I can fully understand this one.

Chris
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post #204 of 446 Old 02-13-2020, 12:49 PM
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So, for fun and because we are still talking about budget here....
@redfive you are pretty awesome for that unofficial Dual sim and not only did you lower the tune to 18hz it also looks like you got it to play to 100hz. It also looks like only 3db (??) down at 20hz. Hmm.
Interesting stuff.

This first graph is from the Quad taken from the beginning of this post.


This is the Dual red five just posted up.


And for fun this is my pa460 narrow mini dev. This box has a great design if you wanted to / needed to upgrade by changing to a different driver and amp without changing the box.
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post #205 of 446 Old 02-13-2020, 01:06 PM - Thread Starter
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Originally Posted by MTBDOC View Post
Nice (ongoing!) work, Chris! Your dedication and effort have been outstanding. Two things really strike me:


  1. How FAST you were able to construct this beast. I realize you have lots of building experience, but this is obviously far more complex than a simple Marty-type box.
  2. Your commitment to chasing data, going far beyond the call of duty to keep getting more measurements outdoors.
I will keep following along, especially for your subjective thoughts. I still am a bit mystified about the "devastator sound" that keeps being thrown around. You aren't a guy to get suckered into $1000 cables, but I do realize that there is more to sound than a simple frequency plot. I built a couple of mini-Martys a month or two ago, but haven't begun to dial in my theater as I also have dining room furniture taking up space as I have other projects ongoing (next comes wainscotting for the dining room). I have run this room in "wide mode" for years, but will likely redo the theater "long ways" [16 ' x 22', very open to lots of other space]. Deciding what further subs to build is part of that.


I guess I am curious as to how people with Dev experience rate this quad. Not just as a 'budget' build, but as a devastator PERIOD. How it sounds & performs relative to others with the usual drivers. I have seen some comparative graphs, but await further thoughts on this. IIRC you also said that this was an easier build in some ways.


Carry on, sir!

Thanks!

Compared to many people here, I really don’t have much build experience. I do consider myself a fast learner, lol.

Both the super fast build and the easier assembly come down to the same thing: Reduced time spent on finish and and perfection. Since this was built as a test cabinet/shop sub, I spent way less time on the visually-perfect aspect that I generally strive for. I still was just as careful with panel fitment, leaks are bad.

In general, building one of these will go exactly the same as building any other Devastator. The quad has a slight advantage from not having a port back, and a slight disadvantage from having four driver cutouts, but neither is greatly significant.

The Devastators are the first and only horns I’ve played with. Pretty much everyone using horns describes how they sound different than direct radiators. The “Devastator Sound” is likely just the horn sound, though the dev’s shared climbing frequency response may factor in heavily as well.

I plan to build a very large front loaded horn, and a pair of large tapped horns in the near future, so I’ll have a better idea once they’re running. I’m also building another Devastator variant, the Alpha, so I should have a pretty good handle on the sound.

I took my 18ds115 out of an mbm, and put it into the mini Devastator. Same general placement. Absolutely huge difference in character of sound, and it wasn’t just the additional 20-37hz range.

I will finish up tuning and subjective testing today. As well as opening it up a bit on the additional power.
I will take some in-room distortion sweeps at various levels, not sure if and how they will be informative.

Chris
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post #206 of 446 Old 02-13-2020, 01:07 PM
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The Devastators not only have a signature tone, they do scary things, things the 11cuft 18Hz tuned 21DS115 just did not do. The sudden dynamic is what really stands out and gets freaky. Something will come out so loud, fast and effortless, yet somehow violent you wonder if the woofer is okay? Then you look at the Nuke and see only the -24db light was on for what just took place... Are V4s necessary? Heck are some JBLs even necessary? Probably not...
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Originally Posted by Audiophile75 View Post
So, for fun and because we are still talking about budget here....
@redfive you are pretty awesome for that unofficial Dual sim and not only did you lower the tune to 18hz it also looks like you got it to play to 100hz. It also looks like only 3db (??) down at 20hz. Hmm.
Interesting stuff.

This first graph is from the Quad taken from the beginning of this post.


This is the Dual red five just posted up.


And for fun this is my pa460 narrow mini dev. This box has a great design if you wanted to / needed to upgrade by changing to a different driver and amp without changing the box.


John design a completely different cab, whereas I was simply assuming we were chopping the quad in half.
Personally, I’d generally prefer the 48x28 profile to 40x36, but this is absolutely dependent on your available space.

The higher QW tune is due to the shorter radiator in the 40” box. This concerns me in two ways.
First, the bottom driver is getting very close to the bottom of the qw, and I’m not sure what that will cause.
Second, we haven’t yet established the reason for the massive resonance at 130hz. If its due to rear chamber height or qw length, as we suspect, it should move up. If its caused by something else, it may still limit bandwidth to 80hz.

I will get the pillow test done tonight, should check the rear chamber possibility.

Chris
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post #208 of 446 Old 02-13-2020, 01:21 PM
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Quote:
Originally Posted by Red Five View Post
The Devastators not only have a signature tone, they do scary things, things the 11cuft 18Hz tuned 21DS115 just did not do. The sudden dynamic is what really stands out and gets freaky. Something will come out so loud, fast and effortless, yet somehow violent you wonder if the woofer is okay? Then you look at the Nuke and see only the -24db light was on for what just took place... Are V4s necessary? Heck are some JBLs even necessary? Probably not...

Okay, thanks. I go back to your first 9-JBL box, and have pondered a 4 JBL ported box. One problem (and I have been trying to read up on it, but still am not clear) is using WinISD in that it models far longer ports than apparently are needed in the 'Marty' scheme. Things like a miniMarty UM18 graphed against 4-JBLs in a similar box ... and the Quad Marty compared to this Quad dev. Frequency response at (for example) 1200 watts (estimate for max JBL ... ignoring for a moment that we really would be looking at V rather than V^2/R). Subjective "effortless" LF does sound quite intriguing.


Then (as I have mentioned before) I still have the 2 old HE-15 drivers that I have pondered mating with SLAPS. Probably ought to sell those drivers to someone who needs small box oomph. Anyway, I am rambling on, but you folks really have gotten my mind engaged in all of this!
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post #209 of 446 Old 02-13-2020, 01:27 PM
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Originally Posted by a77cj7 View Post
John design a completely different cab, whereas I was simply assuming we were chopping the quad in half.
Personally, I’d generally prefer the 48x28 profile to 40x36, but this is absolutely dependent on your available space.

The higher QW tune is due to the shorter radiator in the 40” box. This concerns me in two ways.
First, the bottom driver is getting very close to the bottom of the qw, and I’m not sure what that will cause.
Second, we haven’t yet established the reason for the massive resonance at 130hz. If its due to rear chamber height or qw length, as we suspect, it should move up. If its caused by something else, it may still limit bandwidth to 80hz.

I will get the pillow test done tonight, should check the rear chamber possibility.

Chris

That is why I am not moving too far on this one yet, that was napkin math. I would like to push the QW peak higher up and get the distortion out of high excursion zone if possible, but like you say we do not know the cause of the 130Hz breakup is yet. If I leave the 1.5" on each side of the cutout the baffle would be 14" wide, the sides would push us up to 15.5" wide. Some stuff will have to be done to the design of the cabinet. Then does excursion get weird based on the wiring is the next question... The nice thing on the pillow test, that 130Hz mess will show up low volume near field and indoors

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post #210 of 446 Old 02-13-2020, 01:42 PM
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Hey Josh, are you going to add this build to the data-bass?

Well...a77cj7 gave me almost enough data to do it. Only thing he is missing is an impedance measurement and the burst tests which REW can do although it is a PITA and they don't quite exactly match Don K.s program or CLIO from what I've tested. It was within 1dB though.
Have to figure out just how accurate the SPL is though. 6dB difference is a LOT.

We had always planned to have an area for "unofficial" tests to be hosted.


Quote:
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@Ricci

I’ve been trying to diagnose/verify my mic calibration.

Popped the umik apart, verified dip switches are set for 0db.

Got out my old dayton imm-6 iphone mic. Levels displayed are WAY off.

Tried some iphone spl apps, waste of time as expected.

Gave up, and ordered a cross-spectrum calibrated cm-140 spl meter. I probably should have one anyway.

Chris
I'd have gave you my old CM-140 for the shipping costs. Sadly I'm not too confident in the CM-140's accuracy. The 2 I tested never were very close and the fit into a calibrator was odd / non standard which caused verification issues. An SPL calibrator would've been a better buy. Not trying to bust your chops, just keepin it real. I could probably loan you one if you really want to check into it.

I will have a look at the data in depth as soon as I can but I'm busy for the next few days. It'll probably be next week. Sorry.
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