WinISD Modeling Dayton PRs? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 43 Old 05-17-2020, 07:38 AM - Thread Starter
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Figured it out ... deleted!

 

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post #2 of 43 Old 05-17-2020, 10:10 AM
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A nicer program for PR design:

http://audio.claub.net/software/kougaard/ubdwnld.html

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post #3 of 43 Old 05-17-2020, 10:26 AM - Thread Starter
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Thanks Noah... Bored sh$tless at home these days. Thought I'd start modelling what the AV15H might look like with two of the Dayton 18"PRs.

Have only ever modeled sealed designs 10 years ago so not really sure what I'm looking for in terms of tune, grams, box size etc.

Still recall everyone raving about the possibility of the AE AV15H 1512 boxes or whatever they were called that never really came to fruition. I think they were 24x24x25 so around 5.5cubes as they were 1.5“ thick.

 

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post #4 of 43 Old 05-17-2020, 01:13 PM - Thread Starter
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Hmmm...unless I'm modeling it wrong (don't have excel on this laptop so using WinISD), the AV15H in an ~8cubic foot box, 25x24x25 interior dimensions before drivers, ends up with a fairly high tune?

IIRC, the boxes that were modeled with the AE 18" PR's had around 2500 grams in total PR mass, and only 1,000 is doable on the Daytons, is that the reason those boxes had around a 16hz tune vs the 23hz on this box?

..plus looking at sketchup, I'd want to reduce that box size a couple inches each way to not having a ton of waste, which would then push the tune closer to 26hz or higher. If I modeled it right, that's dissappointing!
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post #5 of 43 Old 05-17-2020, 07:07 PM
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Yes, lower mass raises PR resonance and Fb.

Check out this thread https://www.avsforum.com/forum/155-d...ranking-s.html , Mach 5 makes PR's that can handle several kg added mass.

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post #6 of 43 Old 05-18-2020, 04:15 PM - Thread Starter
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Thanks Noah, have reached out to Mark. Thinking of "reviving" the AV15H dual 18" PR 24x24x25" sub. Hoping it will give me a lot more output given I've gone from a 12x17x9 family room to a 18x26x10 that is also open to a kitchen. The sealed config is quite anemic compared to what it was in the smaller room. Not chasing <15hz sort of thing, just want better output from 20hz to 40hz.

If I can reuse the AV15H drivers, all the better.

Modeled up something like this, possibly in a white stain to compliment the existing white cabs.
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post #7 of 43 Old 05-18-2020, 04:17 PM - Thread Starter
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Have reached out to Mark and to John. With the USD exchange and shipping costs, getting it from John may be a challenge!

The Dayton 18" PR's don't seem like a match as they seem to only go up to 1,100 grams. I think that is the total weight after adding the 8 discs, but not sure as it's a bit unclear in WinISD whether the T/S specs of the Dayton starts at 500 grams and I "add" 600 grams in WinISD to the PR's, or if I add 1,100 grams to the model.

 

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post #8 of 43 Old 05-18-2020, 04:42 PM - Thread Starter
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Hmmm....maybe with a grill if I can add another 1" to the top/bottom pieces without needing to use another sheet.
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post #9 of 43 Old 05-18-2020, 06:30 PM
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Yeah the Dayton PR's look really nice but don't handle much mass added. 1100g is nothing for an 18" PR in a reasonably small box. Add a second PR and you're even more off in the woods.

The Mach5 is nice so far, I need to beat on it a little and see how she does.
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post #10 of 43 Old 05-18-2020, 06:42 PM
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Quote:
Originally Posted by pbc View Post
Have reached out to Mark and to John. With the USD exchange and shipping costs, getting it from John may be a challenge!

The Dayton 18" PR's don't seem like a match as they seem to only go up to 1,100 grams. I think that is the total weight after adding the 8 discs, but not sure as it's a bit unclear in WinISD whether the T/S specs of the Dayton starts at 500 grams and I "add" 600 grams in WinISD to the PR's, or if I add 1,100 grams to the model.
Mms is moving mass of a normal cone, coil, including acoustic load. Mmpr is same, just for a PR (no coil, obviously).

If you had a Mmpr of, say 550g, and you added 550g you'd have 1100g total. You would then first re-calculate Fpr (resonant freq of PR, same as Fs but for PR) then you would re-calculate Qmpr, which is the mechanical Q of the PR at Fpr.

So, to answer your question you add 600g unless they specify "you can add up to 1100g" vs "maximum mass of 1100g". Make sense?

Edit: yes, 1100g is max mass. You can see you can add up to 8 disks, each disk being 75g. So you can add up to 600g.
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post #11 of 43 Old 05-18-2020, 07:00 PM - Thread Starter
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Hey Chris.. I was jealous of your PR build so thought I'd look into one with my AV15H... Just kidding, yours are going to be killer. But I can't put that size boxes into my family room!

What I couldn't figure out in WinISD is whether the default specs of the Dayton PR assumed a mass of 500 Grams and so in WinISD I would simply enter 600 additional grams... Or 1100 grams.

In any event Mark is seeing what he can cook up.

How long did it take for you to get your PRs?

 

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post #12 of 43 Old 05-18-2020, 07:55 PM
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Well, hard to say since Mark got delayed like the rest of the world with the Covid19 situation. I sent an inquiry Mar 28, got a response from him the next day stating he could do it but there would be delays, long story short they were delivered May 5. I consider that very reasonable in this current world situation.

My interactions with Mark were pleasant, but understand I'm not a high maintenance customer. I state what I want, they come as close as they can to it, I'm super pragmatic and flexible at this stage of the game.

I will say PSI was quicker to respond right away, but haven't heard zip from them since. So I'm not sure how things are going for that business in this world situation, but I'll damn near always give my money to the guy that responds -and acts. So unless I have some issues when I do higher power testing, Mark is my current go-to recommendation.

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post #13 of 43 Old 05-19-2020, 09:36 AM - Thread Starter
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So reached out to Mark, and he specs the 18" PR as:

Fs - 23Hz
Qms - 8
Sd - 1209cm2
VAS - 240L
Xmax - 35mm

...and can add mass from there.

So I put this into WinISD assuming a 5.5cubic foot box (which takes into account driver displacement volume). Given the size of the rooms these will be in, I'm targeting around a 20hz tune which seems to require around 2000 grams.

Curious, this is the transfer function magnitude graph and the SPL graph, should I be concerned with that modeled behaviour not being flatter?

Not sure I understand how the transfer function magnitude graph works vs the SPL graph (in plain english anyhow). Just want to make sure I don't end up needing significant boost (obviously the room will have a huge impact on this).
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J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 


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post #14 of 43 Old 05-19-2020, 09:59 AM
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Quote:
Originally Posted by Chris Popovich View Post
...You would then first re-calculate Fpr (resonant freq of PR, same as Fs but for PR) then you would re-calculate Qmpr, which is the mechanical Q of the PR at Fpr.

That's what's nice about UniBox, when you increase mass it will recalculate those for you.


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Originally Posted by pbc View Post

Curious, this is the transfer function magnitude graph and the SPL graph, should I be concerned with that modeled behaviour not being flatter?

Not sure I understand how the transfer function magnitude graph works vs the SPL graph (in plain english anyhow). Just want to make sure I don't end up needing significant boost (obviously the room will have a huge impact on this).

That response shape looks like EBS (extended bass shelf).

Room gain should bring it up, but hopefully you have some kind of EQ to get what you want.

Transfer Function Magnitude and SPL differ in level and will have the same shape unless you check the box under the Advanced tab that will limit SPL to xmax.

If you don't like the idea of boost, just taper off the rise by cutting.

Noah

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post #15 of 43 Old 05-19-2020, 10:21 AM - Thread Starter
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Okay, trying UniBox on my work laptop, but unless I'm missing something, seems to have a completely different results. I'm guessing I have the mechanical mass wrong?
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post #16 of 43 Old 05-19-2020, 10:22 AM - Thread Starter
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Definitely do not want a 30hz boom box.

 

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post #17 of 43 Old 05-19-2020, 10:25 AM - Thread Starter
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Originally Posted by noah katz View Post
That's what's nice about UniBox, when you increase mass it will recalculate those for you.


That response shape looks like EBS (extended bass shelf).

Room gain should bring it up, but hopefully you have some kind of EQ to get what you want.

Transfer Function Magnitude and SPL differ in level and will have the same shape unless you check the box under the Advanced tab that will limit SPL to xmax.

If you don't like the idea of boost, just taper off the rise by cutting.
Would be using my FunkAudio amp which has Alldsp controls within it, though I'd have to possibly figure out how to lower the output vs 2400x2 (I doubt it actually does that I guess).

 

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post #18 of 43 Old 05-19-2020, 12:09 PM - Thread Starter
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Ah, so it seems when you add mass to the PR in WinISD, WinISD automatically calculates the revised Fs of the PR. E.g., with no added mass the Fs is 23hz, but adding 2000 grams of mass in WinISD drops the Fs to 9.23hz.

But Unibox does not seem to do the same, which is why the FR is so different. Am I supposed to be doing something else in Unibox as I can't imagine we'd have to recalculate the effect of adding grams to PR's by ourselves? But I don't see a macro to do it.

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Originally Posted by noah katz View Post
That's what's nice about UniBox, when you increase mass it will recalculate those for you.
Noah - It doesn't seem to recalculate Fr when mass is added?

 

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post #19 of 43 Old 05-19-2020, 12:25 PM
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Noah - It doesn't seem to recalculate Fr when mass is added?

Hmm, you're right, when you do it manually.

But just to the right of F3 is a window where you can click on Mass Up or Down; if you use that it will recalculate everything, including the response.

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post #20 of 43 Old 05-19-2020, 12:38 PM - Thread Starter
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Hmmm, see that. Also didn't realize it calculates Vas automatically. So I can back into what I assume is the existing Mmp amount given Mark provides Vas of 241 but not Mmp.

To get to Vas of 241, I need to insert 815 grams into Mmp.

But to get to the same 9.23hz that WinISD calculates, I need to set Mmp to 5066 grams and the response curve also looks way different than WinISD?
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post #21 of 43 Old 05-19-2020, 12:42 PM - Thread Starter
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Found John's graph above in a similar size box with IIRC 1800 to 2500 grams of mass. So the WinISD model looks a lot more like this one. Must have something else wrong in Unibox?

 

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J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #22 of 43 Old 05-19-2020, 12:50 PM
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Found John's graph above in a similar size box with IIRC 1800 to 2500 grams of mass. So the WinISD model looks a lot more like this one. Must have something else wrong in Unibox?

The red curve looks a lot like UniBox's.

Not sure I'd assume WinISD is getting it right vs. UniBox, which seems more technical to me, as it allows more visibility and user control.

Sorry but I've got other things going on and don't have time to figure this out.

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post #23 of 43 Old 05-19-2020, 12:52 PM
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I've only used BassBox 6 Pro seriously, thus far it's been very accurate for anything I've done. IIRC bought the software in the late 90's or very early 00's. Still chugging along!
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post #24 of 43 Old 05-19-2020, 12:53 PM - Thread Starter
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Thanks for the help in the mean time Noah...will see if I can figure it out!

 

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post #25 of 43 Old 05-19-2020, 01:23 PM - Thread Starter
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Okay, think I'm figuring it out, or at least where some of the confusion is. Didn't realize modeling PR's is this painful, to the uninitiated anyhow.

In WinISD you insert the specs of a single PR that you're using when you're setting up your project. I.e., you insert VAS, Qms, Fs, Sd, Xmax. Then once the project starts you can put "2" in the Number of PR's box and it does the math for you to add the second. What I'm not sure about is whether the "added mass to cone" section assumes 1 PR or the total added mass to the system (e.g., in my case 2 PRs). I'm assuming it is mass added to a single PR.

For Unibox, in my base I know the FS (23hz), Qmp (8) and Sd (1209) which are user inputs. I don't know the Mmp, but I do have the Vas, so to get to a Vas of 240l I can back into it with an Mmp of 410 grams, which must be what the weight is before adding any additional mass (checking with Mark to confirm).

After figuring out the above, then I can insert "2" as the number of PRs, then increase grams as needed. I was doing it the other way, which was starting with "2" in the number of PR's then backing into the Mmp to get to a Vas of 240ltrs, when in fact Vas for 2 units would be double that.

Now the graphs are a lot closer to each other, still a bit off in tune but WAY closer to the point where I'm not sure the difference matters since it's simply a model that has other errors in it I'm sure.

 

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post #26 of 43 Old 05-19-2020, 01:57 PM
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Great, glad you figured it out.

Yeah, you reminded me of many confusing times w/WinISD and what's going on with multiple drivers.

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post #27 of 43 Old 05-19-2020, 05:41 PM
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pbc, like you, I'm looking at the possibility of using PR's for my two sealed Eminence 21" NSW's. My space is similar to yours. Regarding the 18" PR's, did you get a price from Mach Audio? How much weight can they take? If I were to go that route, like you, I will like to keep the box size as small as possible. I also had a Funk Audio 2,400watts plate amp for a while but sold it and bought the Speakerpower HT4000 plate amp which to me, is a big upgrade.

I also had one PR sub for a while at least 8-9 years ago. John at Acoustics Elegance made me two 18" PR's of 2,400grams each. I made a 8cf (internal) box with the AV15X, tuned at 16hz. That sub was the total package with plenty of low/mid bass. I wanted another one for a more even bass response and more headroom. As I mentioned before, John stopped making the sub X/H drivers and I ended up selling it and ended up like you, dual opposed boxes but with 15" JBL GTI drivers. You have four 15" AV15H drivers, four small PR boxes? That would give you all the low bass you want and then some.

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post #28 of 43 Old 05-19-2020, 06:24 PM
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Since you're looking for more output in the 20-40hz range, I would use something similar to what John used, 5-5.5cf internal size and tuned to 18hz like he had it. For me, 15-16hz would be good enough. Since you have 15" drivers, you can easily do a few of them in small boxes. I'm more limited in the sence that since I have 21" drivers, my boxes would probably have to be quite a bit larger which will be more of a challenge to fit in the living room and pass WAF.

Last edited by spanish68; 05-20-2020 at 01:49 PM.
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post #29 of 43 Old 05-19-2020, 06:39 PM - Thread Starter
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Yeah, I recall your AV15x. Both John and Mark quoted me for 18" PR's, but with AE being in the US I'd get hit with the exchange rate and I think considerable shipping so seeing what Mark can drum up given he is in Canada.

I'm considering making either 2 or 4 PR boxes, but might only keep 2 of them upstairs and then use 2 in the basement as I plan on finishing that this year. I am not sure I can pass "3" in the family room. Even though you say they're small boxes, a ~25" cube is still a really big box, and bigger than my existing dual opposed subs which I haven't mentioned to the Missus yet.

I'm just wondering how much of a difference say 2 PR based boxes would be vs the two dual opposed. Modeling it shows the dual opposed has a singificant advantage above say 35 to 40hz, with the PR having a decent advantage below that to tune. But I'm thinking given the size of the room the dual opposed likely are struggling period as they wouldn't have anywhere near the room gain I was getting in my 12x17x9 room. My family room is 18x26x10 and then completely open to a kitchen that adds another 15x26x10 or so.

 

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post #30 of 43 Old 05-20-2020, 03:56 PM
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My room is 16' x 25' x 12' (vaulted ceiling) and open to the kitchen which is smaller than yours. My low end room gain does not start until about 24-25hz, very similar to what you are going to get. On your much smaller previous room you felt the subs much more than now due to the greater room gain. How is your seating distance you had before compared to now? Can you adjust the seat(s) to get closer to the subs? I did that a while back and got closer to the subs/speakers and it made some difference with the SPL. Like you mentioned, the gain with the two PR's is going to be small and in a narrow range while you're giving up a lot of mid-bass and ultra low bass gain vs the dual opposed. Unless you're able to due all four PR's in your space, is going to be more of a lateral move, not worth it to me.
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