Newb to diy needing a sanity check on subwoofer plans

[ryanosaur]

That looks like an awesome build! It sounds like these might be a winner then, I think I'll still play with them all in winisd I enjoy learning new skills and it's a good way to practice.

I still need to get my head around size vs tuning frequency and understanding realistic limits as the software doesn't give restrictions it just throws up a response graph (as far as I've seen)

Some of the programs allow for an importing of the response from CLIO data or similar. SoundEasy (and BassBox) has a feature that allows you to enter the curve data manually, which the program will then use to refine its predictions.
For the more serious builder, it then becomes possible to take your own measurements and get that specific Driver’s curve loaded in to the model.
All the programs have their pros and cons. BassBox is easy to get started with but maybe not as advanced as some. SoundEasy is very difficult to learn and work with, but does have some useful advanced features that allow for some potentially better models. LSPcad may be the top of the heap, I know a few designers who use it, but it’s $1K to get!

 

[ryanosaur]

Yes, this RSS315-HF4 is an excellent performer. I have used it for a pair of 3-way speaker cabinets. It has a very smooth frequency response. In a 3.25 cf net volume box, I got an F3 at 25 Hz with a 22 Hz tuning frequency. But we can get even a slightly better LF performance using a bigger cabinet.

This is the 3-way enclosure which I built several years ago:

View attachment 50787

Indeed, you are one of the cat’s I was thinking about!
You used those in your current Speakers, too, ya?

 

[Verdinut]

Indeed, you are one of the cat’s I was thinking about!
You used those in your current Speakers, too, ya?

I use the larger RSS390HF4 subs in the 3 front cabinets.

 

[marticus]

I use the larger RSS390HF4 subs in the 3 front cabinets.

Damn! 3 15s, I wish I had the space...

 

[marticus]

Some of the programs allow for an importing of the response from CLIO data or similar. SoundEasy (and BassBox) has a feature that allows you to enter the curve data manually, which the program will then use to refine its predictions.
For the more serious builder, it then becomes possible to take your own measurements and get that specific Driver’s curve loaded in to the model.
All the programs have their pros and cons. BassBox is easy to get started with but maybe not as advanced as some. SoundEasy is very difficult to learn and work with, but does have some useful advanced features that allow for some potentially better models. LSPcad may be the top of the heap, I know a few designers who use it, but it’s $1K to get!

Thanks for the information, that's very interesting. I'll look into those programs, though I'm not looking to invest 1k into software I think .
Do you have experience with winisd? I tried that because it's free ind I read and heard that it works well, but I have nothing to compare it too.
From my limited understanding winisd does provide you with recommended specs based on your driver choice and build type(sealed, vented, qb, ebs etc).

But from that initial recommendation you are free to adjust the box size, tuning frequency, port diameter etc. And it will generate the graph based on that right, but I don't know how far you can or should realistically push those diameters from the recommended specs. Clearly having a reasonable looking response graph isn't the whole story..

 

[marticus]

OK Guys,

If anyone's still interested I finally had some time to play with winISD this evening. I imported the drives from the loudspeaker database, and (with the exception of one test) let WinISD offer recommended settings, the only thing that i specified was that all the subs were vented not sealed for comparisons sake (for clarity winISD did recommend sealed for several of these drivers, but I wanted to start with one consistent parameter).

OK so lets start with the overall results and go from there, sorry these aren't all to easy to differentiate as the names on the left aren't colour coded to match the graph, but each will be displayed separately.

the obvious outlier at this point is the UM12-22, everything else is hitting f3 between 25 and 30hz, whereas the UM12 is dragging it's ass all the way down past 20hz into the mid teens.

Let's look at the individual results.

 

[marticus]

Dayton RSS315HF-4

WinISD recommended a QB3 (quasi-butterworth) enclosure for this driver with a volume of 75l (2.6 ft3) tuned to 24hz, this gets us an f3 of around 25hz.
This differs from dayton's recommendations (generated with Bassbox) of 2.05 with an f3 of 30hz

 

[marticus]

Dayton UM12-22

Here WinISD, suggested a large C4 Chebyshev enclosure with a volume of 176l (6.2ft3) with a tuning frequency of 17hz.
Again this doesn't match Dayton's (Bassbox) recommendations of 4.0ft3 tuned to 20hz

 

[marticus]

Peerless XXLS-P835017

Here we are getting almost identical volume and results as the RSS315HF-4 with a volume of 75l (2.6 ft3) tuned to 24hz, this gets us an f3 of around 25hz.
And again seems to conflict with Bassbox recommendation (from parts express this time) with the same volume of 2.6ft3 but a claimed f3 of only 29hz (a result of a different tuning frequency i assume).

 

[TLS Guy]

Dayton UM12-22
View attachment 50851
Here WinISD, suggested a large C4 Chebyshev enclosure with a volume of 176l (6.2ft3) with a tuning frequency of 17hz.
Again this doesn't match Dayton's (Bassbox) recommendations of 4.0ft3 tuned to 20hz

Those Dayton UM drivers are not really designed or highly suitable for vented application. They have optimal parameters for sealed enclosures with lots of EQ and a powerful amp.

Parts Express tend to avoid extended bass alignments, which I agree with. The problem with trying to go for the lowest possible F3, is a reduction in bass quality.

Bass Box was developed from the software of a couple of really good speaker designers, Bullock and White. I bought there original software from them in 1984, on Apple Floppy discs. I have to say that software has never steered me wrong, and every alignment has worked pretty much as predicted.

 

[marticus]

SB Acoustics SB SB34SWPL76-4

Here we have a SBB recommendation with an interestingly small volume of only 38l (1.3ft3) tuned at 19hz
getting a smoother rolloff than other drivers but with an F3 of up neared 30hz

 

[TLS Guy]

Peerless XXLS-P835017

View attachment 50852
Here we are getting almost identical volume and results as the RSS315HF-4 with a volume of 75l (2.6 ft3) tuned to 24hz, this gets us an f3 of around 25hz.
And again seems to conflict with Bassbox recommendation (from parts express this time) with the same volume of 2.6ft3 but a claimed f3 of only 29hz (a result of a different tuning frequency i assume).

4 cycles is splitting hairs. That Peerless driver will do what you want at a reasonable price. We had a member build a sub he was very pleased with using that driver.

May be tomorrow I will take a good look at it for you.

 

[marticus]

Scanspeak 30w-4558T00

WinISD gives us another SBB enclosure for this one, with a volume of 91l (3.2ft3) tuned all the way down at 17hz but giving us an f3 of around 27hz.

 

[marticus]

SEAS SW300-1_L0020-45

Heres our last and an an interesting one, WinISD suggests a HUGE volume of 238l (8.4ft3) tuned to 17hz which buys a an f3 of high teens.
Wholly impractical, but interesting nonetheless.

 

[marticus]

Those Dayton UM drivers are not really designed or highly suitable for vented application. They have optimal parameters for sealed enclosures with lots of EQ and a powerful amp.

Parts Express tend to avoid extended bass alignments, which I agree with. The problem with trying to go for the lowest possible F3, is a reduction in bass quality.

Bass Box was developed from the software of a couple of really good speaker designers, Bullock and White. I bought there original software from them in 1984, on Apple Floppy discs. I have to say that software has never steered me wrong, and every alignment has worked pretty much as predicted.

Yes I believe it, as I said in a previous post, this exercise was more an opportunity for me to experiment with WinISD and get an idea of how it's results compare to manufacturers / Bassbox recommendations.

It's interesting that in some cases they differ and others they are fairly close. I'm wondering now if the driver specs imported from the driver database are up to date / accurate.

I will probably follow up this exercise with some models based on the Bassbox recommendations, it would be interesting to see if the resulting graphs are similar.

 

[marticus]

4 cycles is splitting hairs. That Peerless driver will do what you want at a reasonable price. We had a member build a sub he was very pleased with using that driver.

May be tomorrow I will take a good look at it for you.

That would be very helpful thanks! it will be interesting to see how the graphs compare.

This is one of the more interesting options for me, with a realistic volume and reasonable results

 

[marticus]

Conclusions? nothing concrete yet.

Evidently WinISD and Bassbox Pro don't agree with one another about recommendations, whether this is because of incorrect driver specs or some other variable I don't know yet.

As I mentioned in the first of these posts and @TLS Guy has already pointed out, Vented is not the optimum design for all of these drivers, this was more about comparisons, and Dayton do provide specs for vented as i've used to compare.

At this point i guess the most interesting / realistic are the dayton reference, and peerless models.

As the useage for this is mainly movies the idea of a <20hz f3 is certainly appealing but not at any substantial cost of quality, as we might expect with the Dayton UM12, and certainly not if the box is going to be over 8ft3 lmao.

next steps will be to try again based on manufacturer / bassbox settings and compare them to @TLS Guy graphs if he has time to do some.

from there i need to find out how far i can 'push' the settings without sacrificing quality to any substantial degree.

 

[marticus]

Some more quick observations here, i'm not trying to turn this thread into my own blog or anything, but its a good place to compile my thoughts, and hopefully you guys will feel free to jump in and let me know when i'm jumping to incorrect conclusions or missing some information.

So for now i've dropped the UM22 and SEAS drivers out of the running, and am focusing on the remaining four.

I decided to check output and by extension efficiency (at least that's my assumption).. The driver range from 120w RMS for the Peerless, to 400w RMS for the dayton.

I fed them all 120w initially in the simulation, to see how they stacked up:

we see the SB Acoustics driver (in red) down at the bottom of the graph about 3db down from the Scanspeak driver (in green).

Up on top we have the Dayton and Peerless drivers sharing pretty much exactly the same response with a little 1db bump at 30hz.

 

[marticus]

But of course all is not fair in love, war, or speaker SPL outputs. So lets feed the drivers their specified RMS rated power:

Here we see things evening out, the SB acoustics driver has caught up with the Scanspeak and peerless competition, due to having double the power handling (300wRMS vs 150w for the Scanspeak and 120w for the Peerless), all putting out exactly 106db @30hz..

But coming out on top is the Dayton driver with a 400w RMS power handing, which will put it up 5db above the competition at 30hz.

@ 106db, where everything else is at 30hz, the dayton is outputting nearer 22hz!

 

[marticus]

Quick question about amplification, if anyone can help?

If we take the dayton driver as an example (400w RMS / 800w max), what sort or power level should I be aiming for here, obviously I don't want to overdrive the sub, but underpowering it won't help either right?

Should I aim for the max figure of 800w? Or would something like 500w of amplification be sufficient?