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Droogne

Dayton Audio Ultimax UM18-22 in a 24 cuft enclosure: what design?

What design?  

3 members have voted

  1. 1. What design would fit the best with this driver and (fixed) enclosure volume?

    • Single driver, sealed
      0
    • Doubledrivers, sealed
      1
    • Triple drivers, sealed
      0
    • Single driver, ported
      0
    • Double drivers, ported
      2
    • Single driver with Passive Radiators
      0


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On 4-11-2017 at 12:06 AM, Infrasonic said:

I knew there was a reason I liked you. :P

Ehhh.... soundwise, wah? It's a riser.

Just make sure to uhh....do whatever SME says with the "sealed" and all that stuff. :P

What would you say about a https://www.brl.se/sv/artiklar/b-audio-is15-d4v3-2x4ohm.html ? It's only 15", but pretty cheap so I could buy 2 for the price of 1 Ultimax. 

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On 25-10-2017 at 7:46 PM, Infrasonic said:

What I mean is trying to attain a finished product with a "F3 of something..." will be irrelevant because that F3 you simulated will no longer be the actual inroom F3. 

The riser will extend down as low as your electronics and displacement allow.

Have been looking into some more cheap subs, and it did take me a while, but I have found some good candidates! Due to the depth of woofer a 15" would suit me better. For the price of some of the 15" I have found recently I could easily build 2 for the price of 1 Ultimax with money to spare. The one I linked above is an example, but I'v also found a even cheaper model. The "Avatar SST-2515D2", specs:

SPL 87,00 dB
Fs 29,00 Hz
Qts 0,60
BL 19h00
Re 14 + 1.4
Vas 65.00 L

It only costs 170 eu which means I could make 2 now for 100eu cheaper than the Ultimax. What do you think about those specs? Good fit for my riser? I can then use that saved money to put towards a nice pair of 18" ported subs (tuned to 20hz) or maybe to another pair of the 15s to also make 2 "behind the couch" VNF subs ;) Or maybe try that plan (4 VNF subs) with 4x 12" subs or a combo of 15" and 12" (or other combos and number of subs), specs of the 12":

SPL 85,50 dB
Fs 30,00 Hz
Qts 0,56
BL 18h00
Re 1.4 + 1.4
Vas 56,00 L
Xmax 26,00 mm

 

 

 

  

 

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I'm not familiar with any of those drivers, and I'm not sure anyone else here is either.  Hence, the best we can do is trust that the specs are accurate and give an opinion accordingly.  To me, they appear to have potential for your application.  Have you tried modeling them yet?

The quoted Xmax on all of these come in around 25 ms, which is decent if accurate, especially for the price.  The motor systems on these are nothing to brag about, but that may not be an issue when used only for low frequencies in large volumes like you intend to.  What's not clear to me from merely looking at the specs is how much the suspension stiffness is going to hold things back.  That could be an issue.  Other than that, I don't see any specs with regard inductance or any evidence of inductance management.  For the price, I'm guessing these aren't too good at handling mid bass frequencies, but it looks like you have the PA sub that can handle that and may build others.

So to summarize, these look like they could work, but don't take my word for it without at least modeling them.  Also note that 15" has a lot less displacement than 18", and 18" is almost always more economical than 15" if you want as much displacement for the $ as possible.  A lot of times, the mounting depth for an 18" is no different than a 15", so do take a look at that before committing to 15"s.

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1 hour ago, SME said:

I'm not familiar with any of those drivers, and I'm not sure anyone else here is either.  Hence, the best we can do is trust that the specs are accurate and give an opinion accordingly.  To me, they appear to have potential for your application.  Have you tried modeling them yet?

The quoted Xmax on all of these come in around 25 ms, which is decent if accurate, especially for the price.  The motor systems on these are nothing to brag about, but that may not be an issue when used only for low frequencies in large volumes like you intend to.  What's not clear to me from merely looking at the specs is how much the suspension stiffness is going to hold things back.  That could be an issue.  Other than that, I don't see any specs with regard inductance or any evidence of inductance management.  For the price, I'm guessing these aren't too good at handling mid bass frequencies, but it looks like you have the PA sub that can handle that and may build others.

So to summarize, these look like they could work, but don't take my word for it without at least modeling them.  Also note that 15" has a lot less displacement than 18", and 18" is almost always more economical than 15" if you want as much displacement for the $ as possible.  A lot of times, the mounting depth for an 18" is no different than a 15", so do take a look at that before committing to 15"s.

The 250eu model (B2 Audio) gave me very good results when modeled in winISD, but almost too good (although the specs I put in were confirmed to be correct by their support. See an example below. I'm bit baffled by the fact that (in a 100L cabin) I only reach max excursion at 1250 watt... Is this normal, or did I maybe enter some unrealistic parameters? see below. [EDIT: I think I might have put in some extreme EQ parameters which messed up this result, not sure. Will have to check tomorrow]. SPL sheet is at 750W input, which is its RMS). I dont seem to be able to put the TS parameters into winISD for the Avatar subs (which I found for even less than the 170 which I listed before, it's 130eu now), as it gives me a "divide by 0" error... I will not be buying this one without having a decent spec sheet. I have asked them about it, so I'm hoping they can give them to me. 

As for cost ratio, would you say a 1,44 ratio is correct (due to cone surface, without taking the power handling in consideration). In that case the 130 (or even 250eu) are still a lot cheaper (130*1,44=187 and 250*1,44=360. cheapest 18" one would be a SI 18HT for 305 incl. import etc, so this one would be the best 18" price/quality ratio, and better than the 250eu one, but it's not for sale anymore :( , the Dayton would cost a 100eu more, and any other 18" subs with a good Xmax are not really within my range for this price). 

 

I've found yet another 15" sub (with a lot of info lacking, so I inquired into this one too) for a very low price, 129 to be exact:

RMS 450 W
X Max(BL 50%) 32 mm
Re 3,3 ohm
Fs 29,5 Hz
Qts 0.7
Sd 819 cm²
Vas 91,8 L
BL 14,8
Sens (1W/1m) 87,8 dB
Sens (2,83Vrms/1m)

91,5 dB

 

About the mouting depth, I have to agree that it's not a lot of difference, and I have no idea yet what my max tolerable height will be, but I'll be testing that over the next few days/weeks so I now for sure that the ca 4-5cm (1-2 inch) is gonna make a real difference. 

B2Audio excursion.PNG

B2AudioSPL.PNG

B2AudioTSP.PNG

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20 hours ago, Droogne said:

The 250eu model (B2 Audio) gave me very good results when modeled in winISD, but almost too good (although the specs I put in were confirmed to be correct by their support. See an example below. I'm bit baffled by the fact that (in a 100L cabin) I only reach max excursion at 1250 watt... Is this normal, or did I maybe enter some unrealistic parameters? see below.

Unrealistic?  Not necessarily.  However, I notice your simulation shows excursion dropping off rapidly below 15 Hz.  That's probably not realistic.  IIRC, the "Pro" version of WinISD has a particular Q parameter ("Qloss"?) defined for the system that accounts for losses due to air leaks and wall flexure.  If exists in your version, I don't see it defined on any of the dialogs you show.  I recommend trying to find and then making that Q value really high to effectively disable its contribution because it's true value is unknown and likely to be a lot higher than the default anyway.  That will give you a more realistic projection of ULF output and excursion.

20 hours ago, Droogne said:

I dont seem to be able to put the TS parameters into winISD for the Avatar subs (which I found for even less than the 170 which I listed before, it's 130eu now), as it gives me a "divide by 0" error... I will not be buying this one without having a decent spec sheet. I have asked them about it, so I'm hoping they can give them to me.

Assuming you are entering the same type of parameters as for the other drivers and that you didn't make any errors, that does not give me confidence that the program is working reliably.  Have you looked for "WinISD Pro"?  IIRC, that's the version that's recommended for use these days.

20 hours ago, Droogne said:

As for cost ratio, would you say a 1,44 ratio is correct (due to cone surface, without taking the power handling in consideration). In that case the 130 (or even 250eu) are still a lot cheaper (130*1,44=187 and 250*1,44=360. cheapest 18" one would be a SI 18HT for 305 incl. import etc, so this one would be the best 18" price/quality ratio, and better than the 250eu one, but it's not for sale anymore :( , the Dayton would cost a 100eu more, and any other 18" subs with a good Xmax are not really within my range for this price).

Yes, approximately.  In reality, the effective diameter of each driver cone is a bit lower than the nominal diameter, so the ratio is a bit higher, more like 1.5.  Keep in mind too that this only works when comparing drivers with similar Xmax.  And when looking at price, also consider what amp power you need to drive everything as that is often as expensive or more expensive than the drivers.

That's a bummer that the 18HT was discontinued.  I noticed that some of the drivers you posted are also manufactured in 18" versions, which is why I thought I'd point that out.

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18 minutes ago, SME said:

Unrealistic?  Not necessarily.  However, I notice your simulation shows excursion dropping off rapidly below 15 Hz.  That's probably not realistic.  IIRC, the "Pro" version of WinISD has a particular Q parameter ("Qloss"?) defined for the system that accounts for losses due to air leaks and wall flexure.  If exists in your version, I don't see it defined on any of the dialogs you show.  I recommend trying to find and then making that Q value really high to effectively disable its contribution because it's true value is unknown and likely to be a lot higher than the default anyway.  That will give you a more realistic projection of ULF output and excursion.

Assuming you are entering the same type of parameters as for the other drivers and that you didn't make any errors, that does not give me confidence that the program is working reliably.  Have you looked for "WinISD Pro"?  IIRC, that's the version that's recommended for use these days.

Yes, approximately.  In reality, the effective diameter of each driver cone is a bit lower than the nominal diameter, so the ratio is a bit higher, more like 1.5.  Keep in mind too that this only works when comparing drivers with similar Xmax.  And when looking at price, also consider what amp power you need to drive everything as that is often as expensive or more expensive than the drivers.

That's a bummer that the 18HT was discontinued.  I noticed that some of the drivers you posted are also manufactured in 18" versions, which is why I thought I'd point that out.

iNukes are sold at laughing prices over here so amp power is almost negligible, but I get your point :) wiring 2 15" in series instead of 1 18" would give me more power to begin with. And if the Xmax is correct, the 15" got an even better value as their Xmax is higher (the pride one even has one that is almost 1,5 times as high as the Ultimax which puts it at the same level, for 1/3th of the money). And yeah, the 15s have 18 versions, but for some reason those are A LOT more expensive. Way more than the Ultimax.. So for 18" the Ultimax still reigns. I also get a 15% discount when buying 4 of the 15s at once which puts it at even higher value. Really need to get those other TS parameters! 

Concerning winISD pro, I have no idea why I'm not using it already.. I tried it , but cant remember why I switched back to the normal version. Will try out it and run the 15"s vs the Ultimax. 

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13 hours ago, SME said:

Assuming you are entering the same type of parameters as for the other drivers and that you didn't make any errors, that does not give me confidence that the program is working reliably.  Have you looked for "WinISD Pro"?  IIRC, that's the version that's recommended for use these days.

Also, it's not that winISD was failing, it's more like this driver only had like 5 parameters, no Qes or Qms, which I think was the problem. All those other drivers I put in had A LOT more inputs. 

Which TSP would you say are necessary to reliably model a woofers performance? 

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18 hours ago, Droogne said:

Also, it's not that winISD was failing, it's more like this driver only had like 5 parameters, no Qes or Qms, which I think was the problem. All those other drivers I put in had A LOT more inputs. 

Which TSP would you say are necessary to reliably model a woofers performance? 

Several different sets TS parameters are sufficient to model a woofer.  Of the parameters that are typically specified, many are redundant and can be calculated from some of the others.  As such, it's kind of hard to succinctly describe which parameters are absolutely required.  For example, one commonly used set consist of: Fs, Vas, Qes, Qms, Re, and Sd.  Frequently, Mms is substituted for Fs.  BL may be substituted for Qes.  Rms may be substituted for Qms, and so on.  Only five parameters is definitely not enough, although if they don't give Re in the TS list, you might be able to find that info elsewhere.

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3 hours ago, SME said:

Several different sets TS parameters are sufficient to model a woofer.  Of the parameters that are typically specified, many are redundant and can be calculated from some of the others.  As such, it's kind of hard to succinctly describe which parameters are absolutely required.  For example, one commonly used set consist of: Fs, Vas, Qes, Qms, Re, and Sd.  Frequently, Mms is substituted for Fs.  BL may be substituted for Qes.  Rms may be substituted for Qms, and so on.  Only five parameters is definitely not enough, although if they don't give Re in the TS list, you might be able to find that info elsewhere.

Thanks, I tried it out with the Pride sub (32mm xmax) and it gives me this: when EQd flat between 10-20hz the xmax is only met at 2150watt 2ohm, this translates into 97db. When taking the RMS into consideration I get 88db flat between 10-20hz (not included in the pics but also 93db 15-30hz, 87db 10-30hz, and flat 83db between 5-20hz.)(take into considertion I can buy 3 of these for the price of 1 Ultimax, so take this spl and add 4,8. I'll do the Ultimax later this day). Still not sure how much the EQ influences the SPL. How do I know much the SPL is gonna be with a certain EQ and a certain max power input (as I can change the spl by changing the EQ without touching the power rating...). Is there maybe a rule of thumb  on how much watt this takes? OR am I misunderstanding the whole situation? 

 

Also, I might have asked this before, what is a good spl level to aim for? I know THX is 95db continious with 115db peaks. How do I use this info? Should I aim for a 112db @RMS (so the peaks are at 118db)? Not sure how I would ever get there haha (even with 18" I'd need plenty of those), I can get to 100db 15-30hz with 4 of the ones mentioned above. 

PrideLP15D2excursionv1.PNG.eecc5de151a57d13c56eec950b9c596d.PNG

LP15D2spl+EQv1.PNG

PrideLP15D2onvoll.specsakav1.PNG

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I think the "Series Resistance" parameter in the dialog you show is for the resistance of the wire going to the drivers.  Just set it to zero.

The EQ option is there to show you EQ will effect the response shape, and this shape change.  What it shows in the SPL output view, however, is not the output you'll see for the power input you specified.  The EQ you specify is applied to the curve in the SPL output without consideration of the additional power and voltage requirements to achieve the output.  Remember, SPL at any frequency is always limited by excursion, voltage, or power, whichever runs out first.  For evaluating the driver and cabinet, I recommend you don't use the EQ feature to avoid confusion.

As for what SPL to aim for, that depends on how you listen and on the in-room response, which varies between rooms and different placements of sub and listener.  It also depends on the nature of the content.  Movies at or near reference level can demand a lot of output.  Designing for 130 dB SPL down to 30 Hz is not reasonable with 120 dB or even higher down to 15-20 Hz.  Output in the mid one-teens appears to be sufficient below there for most films, but there are exceptions.  In most cases, the answer to "how much SPL" is: "the more the better".  However, with the drivers installed in the riser, the actual SPL at the seats may not be as important as the amount of vibration felt at the seats, so you might be able to get away with turning them down a bit more.  You discussed building ported subs for the corners with some bigger beefier drivers, and those seem like the way to go for the higher SPL stuff.

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On 3-12-2017 at 10:44 AM, SME said:

I think the "Series Resistance" parameter in the dialog you show is for the resistance of the wire going to the drivers.  Just set it to zero.

The EQ option is there to show you EQ will effect the response shape, and this shape change.  What it shows in the SPL output view, however, is not the output you'll see for the power input you specified. 

 

On 3-12-2017 at 10:44 AM, SME said:

The EQ you specify is applied to the curve in the SPL output without consideration of the additional power and voltage requirements to achieve the output.  Remember, SPL at any frequency is always limited by excursion, voltage, or power, whichever runs out first.  For evaluating the driver and cabinet, I recommend you don't use the EQ feature to avoid confusion.

If I'm not able to use EQ, how do I know what I can achieve WITH EQ? 

On 3-12-2017 at 10:44 AM, SME said:

As for what SPL to aim for, that depends on how you listen and on the in-room response, which varies between rooms and different placements of sub and listener.  It also depends on the nature of the content.  Movies at or near reference level can demand a lot of output.  Designing for 130 dB SPL down to 30 Hz is not reasonable with 120 dB or even higher down to 15-20 Hz.  Output in the mid one-teens appears to be sufficient below there for most films, but there are exceptions.  In most cases, the answer to "how much SPL" is: "the more the better".  However, with the drivers installed in the riser, the actual SPL at the seats may not be as important as the amount of vibration felt at the seats, so you might be able to get away with turning them down a bit more. 

Sooooo.. from what I've been hearing + what youre saying it does make sense to use 2x 15" instead of 2x 18's, as it's complete overkill. 

On 3-12-2017 at 10:44 AM, SME said:

You discussed building ported subs for the corners with some bigger beefier drivers, and those seem like the way to go for the higher SPL stuff.

Been thinking about that lately. Finding a good (high Xmax) sub on second hand sites is very hard, but I'm not sure what to look for when designing a ported sub. Ive read some things about  Qts (max 0,4) and Fs (max 45hz). Some other parameters that are importing for a "low" tuned ported sub? 

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1 hour ago, Droogne said:

If I'm not able to use EQ, how do I know what I can achieve WITH EQ? 

That's not important.  With EQ, you can reshape the frequency response to be practically whatever you want.  However, this has no effect on the ultimate capabilities of the sub system.  If you need (for example) a 30 dB boost at 10 Hz to make it flat there, you most certainly can do it with EQ.  However, as soon as you play anything remotely loud at 10 Hz, the amps are going to clip or the sub is going to bottom.  The point of the simulation is to see the max capability of the sub, with or without EQ.  The EQ feature in the simulation is likely to mislead you as to the sub's capabilities.

1 hour ago, Droogne said:

Sooooo.. from what I've been hearing + what youre saying it does make sense to use 2x 15" instead of 2x 18's, as it's complete overkill.

Sorry, I wrote a typo in my post.  I was trying to say that 130 dB SPL down to 30 Hz is not unreasonable.  Likewise for 120 dB or higher @ 15-20 Hz.  Those numbers may appear to be extreme, but they aren't far off when reproducing many movie soundtracks at a spirited / reference level.

1 hour ago, Droogne said:

Been thinking about that lately. Finding a good (high Xmax) sub on second hand sites is very hard, but I'm not sure what to look for when designing a ported sub. Ive read some things about  Qts (max 0,4) and Fs (max 45hz). Some other parameters that are importing for a "low" tuned ported sub? 

For a ported sub that's intended to extend low, high Xmax remains important, but motor force becomes more important than for sealed in a large volume.  Investing in pricier drivers with a bigger motor is usually worth it.

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9 hours ago, SME said:

That's not important.  With EQ, you can reshape the frequency response to be practically whatever you want.  However, this has no effect on the ultimate capabilities of the sub system.  If you need (for example) a 30 dB boost at 10 Hz to make it flat there, you most certainly can do it with EQ.  However, as soon as you play anything remotely loud at 10 Hz, the amps are going to clip or the sub is going to bottom.  The point of the simulation is to see the max capability of the sub, with or without EQ.  The EQ feature in the simulation is likely to mislead you as to the sub's capabilities.

Ok, thanks! That makes sense. Still not sure what I can extract from winISD pro in this case.. Just use it to see the response without EQ? And then hope it will perform well with EQ (where a high Xmax will help?) ? 

Quote

Sorry, I wrote a typo in my post.  I was trying to say that 130 dB SPL down to 30 Hz is not unreasonable.  Likewise for 120 dB or higher @ 15-20 Hz.  Those numbers may appear to be extreme, but they aren't far off when reproducing many movie soundtracks at a spirited / reference level.

Aight, but 2x18"s still seemed like a bit overkill for the riser alone (as @Infrasonic told he had to turn down the volume on those, to keep it even with the rest of the subs). Good to know there is almost no limit on how high a low frequency SPL is beneficial! The 130db down to 30hz I can think I can make with my horn sub. Not sure, I'm building it now, so testing it hopefully next week! 

Quote

For a portedx  sub that's intended to extend low, high Xmax remains important, but motor force becomes more important than for sealed in a large volume.  Investing in pricier drivers with a bigger motor is usually worth it.

If 20mm xmax was the goal for the riser, is it still the goal for a ported 20hz sub? Would 15 suffice? And motor force, as in... BI? Qms? Both? If so, what would be good values to look for? I might have a line in on a cheap (VERY cheap) B&C 21SW152, which is a supposedly a very good PA sub, with home use appliances due to it's combo of 21" diameter and 15mm xmax.

image.thumb.png.283e4cc201e17111b61def7296a11154.png

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7 hours ago, Droogne said:

 

Aight, but 2x18"s still seemed like a bit overkill for the riser alone (as @Infrasonic told he had to turn down the volume on those, to keep it even with the rest of the subs).

While this is true I wouldn't use this as any kind of metric to justify anything less capable. You know.... unless you have to. :P

 

 

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13 hours ago, Droogne said:

Ok, thanks! That makes sense. Still not sure what I can extract from winISD pro in this case.. Just use it to see the response without EQ? And then hope it will perform well with EQ (where a high Xmax will help?) ? 

Aight, but 2x18"s still seemed like a bit overkill for the riser alone (as @Infrasonic told he had to turn down the volume on those, to keep it even with the rest of the subs). Good to know there is almost no limit on how high a low frequency SPL is beneficial! The 130db down to 30hz I can think I can make with my horn sub. Not sure, I'm building it now, so testing it hopefully next week! 

If 20mm xmax was the goal for the riser, is it still the goal for a ported 20hz sub? Would 15 suffice? And motor force, as in... BI? Qms? Both? If so, what would be good values to look for? I might have a line in on a cheap (VERY cheap) B&C 21SW152, which is a supposedly a very good PA sub, with home use appliances due to it's combo of 21" diameter and 15mm xmax.

The main thing that WinISD Pro and other simulation programs will tell you is the best-case max output output from the sub + amp system, at 1 meter ground plane.  It's merely best-case because a driver that's pushed near its excursion limits will start to compress and deliver less output.  That's not really easy to model, so it can help if the driver has actually been measured in a cabinet, like Josh Ricci does here.  WinISD Pro can also help you compare different drivers and different cabinet sizes.

As for how much Xmax is enough, well that ultimately depends on how much output you want and whether you'll give it enough amp power to use that excursion.  And unfortunately, the ultimate output you get depends substantially on what your room is doing.  There're just too many variables to give you a clear cut answer.

If building a ported sub, a lower tune will allow for lower extension, of course, but at the cost of output above the tuning frequency.  Lower tunes also generally require larger (and heavier) cabinets.  So there are trade-offs.  If you know you're going to have more than enough output and have no space or weight constraints, then definitely go lower.  Some people build huge cabinets tuned as low as 12 Hz.  (A few aim even lower than that.)

The B&C21SW152 is a solid driver choice for a ported box.  Better yet, lots of people have already built ported systems around it, so you can avoid a lot of design hassle by looking at work that others have done on here and in the AVSForum DIY section.

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On 8-12-2017 at 7:06 PM, Infrasonic said:

While this is true I wouldn't use this as any kind of metric to justify anything less capable. You know.... unless you have to. :P

 

 

Maybe relevant to ask, did you ever do a "side to side" comparisons of your main subs vs your riser? As in, using a dB meter to measure the difference in SPL @1m when you dialed them in/fine tuned them. I might have a big bad PA sub for the+30hz region, but I doubt I will ever use it to even 10% of its power rating. Might get away with a lot less than you as I'm probably gonna be listening at much lower levels. 

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Sub 1 (no EQ): 

image.png.7f9b48de477fc7ace62c29d898c36f98.png

image.png.3c145d9a2acb03cb9a48e13218a5aa62.png

On 9-12-2017 at 1:07 AM, SME said:

The main thing that WinISD Pro and other simulation programs will tell you is the best-case max output output from the sub + amp system, at 1 meter ground plane. 

Just ran it without EQ at RMS. Doesnt exceed Xmax, and only has a -6db drop from 30 to 20hz, and -6db between 20 and 14hz. Decent? 

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9 hours ago, Droogne said:

 

Sub 1 (no EQ): 

[...]

Just ran it without EQ at RMS. Doesnt exceed Xmax, and only has a -6db drop from 30 to 20hz, and -6db between 20 and 14hz. Decent? 

It looks how I would expect with a Q around 0.7 or so.  Every sealed sub essentially rolls off naturally at 12 dB/octave in the low frequency limit, without EQ (and of course, more voltage and power demanded by said EQ).  Excursion always increases 12 dB/octave vs. frequency for the same SPL output.  So once you go low enough, excursion basically remains the same without EQ.  Of course, the roll-off will likely be much less your room.

I gather that's a single driver?  You were going to use 3 of them?  If so, you are hopefully modeling the single driver in 1/3 the total volume.  Now that you've done that, try modeling other drivers in a similar volume and similar voltage.  (See my earlier posts for how to calculate the "wattage" that WinISD Pro expects from actual voltage, and visa versa.)

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On 11-12-2017 at 9:31 AM, SME said:

I gather that's a single driver?  You were going to use 3 of them?  If so, you are hopefully modeling the single driver in 1/3 the total volume.  Now that you've done that, try modeling other drivers in a similar volume and similar voltage.  (See my earlier posts for how to calculate the "wattage" that WinISD Pro expects from actual voltage, and visa versa.)

Yes, that was a single driver in the correct relative volume. I'll have to read the part about voltage again ;) but will do, and get back to you.

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On 12/10/2017 at 3:56 AM, Droogne said:

Maybe relevant to ask, did you ever do a "side to side" comparisons of your main subs vs your riser? As in, using a dB meter to measure the difference in SPL @1m when you dialed them in/fine tuned them. I might have a big bad PA sub for the+30hz region, but I doubt I will ever use it to even 10% of its power rating. Might get away with a lot less than you as I'm probably gonna be listening at much lower levels. 

Yes of course I did. Although I was using the Omnimic system, if that counts.

Noting this, "fine tuning" my riser system had more to do with feel than how it measured audibly.

Trial, error and time listening to (feeling?) actual program material is a major part of the process. It's just not very scientific sounding.

 

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On 11-12-2017 at 9:31 AM, SME said:

It looks how I would expect with a Q around 0.7 or so.  Every sealed sub essentially rolls off naturally at 12 dB/octave in the low frequency limit, without EQ (and of course, more voltage and power demanded by said EQ).  Excursion always increases 12 dB/octave vs. frequency for the same SPL output.  So once you go low enough, excursion basically remains the same without EQ.  Of course, the roll-off will likely be much less your room.

I gather that's a single driver?  You were going to use 3 of them?  If so, you are hopefully modeling the single driver in 1/3 the total volume.  Now that you've done that, try modeling other drivers in a similar volume and similar voltage.  (See my earlier posts for how to calculate the "wattage" that WinISD Pro expects from actual voltage, and visa versa.)

Didnt have any time to look up your previous comment about voltage; but I did model all the models quicky against each other (not sure how to give each curve a color atm). The one that rolls of around 100hz (I might have to recheck those specs) is the B2 Audio sub. If you look at the lower spectrum we have (db wise from top to bottom) the 18" Ultimax (400euro), the Avatar (170euro) and the Pride (130 euro). This was all done in a 100L sealed enclosure.

Any thoughts about this @SME ? 

image.thumb.png.489ccf535ada4fc405c36b137b0a997b.png

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46 minutes ago, Infrasonic said:

Yes of course I did. Although I was using the Omnimic system, if that counts.

Noting this, "fine tuning" my riser system had more to do with feel than how it measured audibly.

Trial, error and time listening to (feeling?) actual program material is a major part of the process. It's just not very scientific sounding.

 

Yeah, it's because of the discrepancy in audible vs feeling that I'm wondering what I should aim for (as feeling isnt shown in winISD ;) ). But I'm guessing there is also a problem in the ratio between audible and tactile output (as in: that 100db of the same linear output would still not feel the same between subwoofers, which would make it problematic to just compare the output of your riser with the output of your main subs). Would it help to know what kind of power you feed into your riser vs your main subs? (to take room gain out the comparison) 

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4 hours ago, Droogne said:

Yeah, it's because of the discrepancy in audible vs feeling that I'm wondering what I should aim for (as feeling isnt shown in winISD ;) ).

Right. Don't worry about it. You'll get what you get.

4 hours ago, Droogne said:

But I'm guessing there is also a problem in the ratio between audible and tactile output (as in: that 100db of the same linear output would still not feel the same between subwoofers, which would make it problematic to just compare the output of your riser with the output of your main subs).

I don't see it as a "problem" but more of an unknown, for you. Don't worry about it.

4 hours ago, Droogne said:

Would it help to know what kind of power you feed into your riser vs your main subs? (to take room gain out the comparison) 

I don't see how it would help out in your case at all, no.

 

 

But... my riser is powered by a single Behringer Europower 4000, bridged to a 4ohm load (two 8ohm drivers in parallel).

My entire front sub-bass system is power by a single Cerwin Vega CV5000 running stereo 2ohm.

The two rear subs are powered by a single Behringer iNuke 4-6000, bridged to two 4ohm loads.

 

 

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10 hours ago, Infrasonic said:

Right. Don't worry about it. You'll get what you get.

I don't see it as a "problem" but more of an unknown, for you. Don't worry about it.

I don't see how it would help out in your case at all, no.

 

 

But... my riser is powered by a single Behringer Europower 4000, bridged to a 4ohm load (two 8ohm drivers in parallel).

My entire front sub-bass system is power by a single Cerwin Vega CV5000 running stereo 2ohm.

The two rear subs are powered by a single Behringer iNuke 4-6000, bridged to two 4ohm loads.

 

 

Just went through your build on the AVS forum (again). Awesome stuff man! Those dual opposed subs are the ones in the front? Are those firing away from the listening position? It seems like you have a loooooot of power (and subs). And even you need to turn your riser subs down? Damnnn. PS on an architectural note, it looks your riser is shallower than I remembered.. how much depth do you have? Or to be more precise, how much place is there free behind your sub, and the floor? I was counting in 2 inches, but could that number be reduced? 

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6 hours ago, Droogne said:

Just went through your build on the AVS forum (again). Awesome stuff man! Those dual opposed subs are the ones in the front? Are those firing away from the listening position? It seems like you have a loooooot of power (and subs). And even you need to turn your riser subs down? Damnnn. PS on an architectural note, it looks your riser is shallower than I remembered.. how much depth do you have? Or to be more precise, how much place is there free behind your sub, and the floor? I was counting in 2 inches, but could that number be reduced? 

Actually, the whole system is quite underpowered but that's okay because I make up a lot with the very high sensitivity. Having a subbass system that is >100dB sensitive means cool running amps too. :D

There are seven subbass enclosures in my HT room. Six identical dual-opposed sealed enclosures. Four up front, two in rear. Each approx. 8cuft each. Four up front house the eight Stereo Integrity HT18's. The two in the rear house four Sound Splinter RLp18's. Then the riser with the last two SS RLp18's.

The riser is very simple. Top and bottom are just some 5/8" or 3/4" plywood. I don't remember exactly. *laughs* Not even really high end stuff either but solid. The walls are made from 2x8's cut to the length I wanted for this size. There is a single 2x4 in the middle (running between the two drivers). The extra baffle pieces were added to accommodate the depth of the RLp driver.

The riser is the only enclosure I've ever built that I didn't really "design". Just thought it up in my head and then simulated to "make sure". Certainly couldn't simulate how it was going to feel. Had to build it to really know for sure.

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