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Thinking of building my first sub, could use input please people.

4229 Views 20 Replies 5 Participants Last post by  Moonfly
OK here is what I want to build:

Twin 15" sealed push/pull design
150 litre cabinet around 500w x 500d x 800h
800 watt amp, or 500 watt BK amp
Amp will be external to allow me to swap and change for experimentation puposes
I want to brace it and need to calculate this
I need to figure out how to calculate stuffing required

Thats basically what I have in mind. If you need to know the particulars of the drivers and amps then they are here:

Drivers
BK amp or this, or something like this Behrringer amp.

I know the Behringer amp isnt a traditional sub amp, but if you consider I'll be using my avr then this amp will power the sub in much the same way as a traditional sub amp in by-pass mode.

My aim is really to replicate the MK MX subs, but going larger with drivers and cabinet to try get the depth I enjoy with my current SVS ultra sub. I really want to go back to a sealed sub, and I can handle a bit of size, but I want to keep the depth of the Ultra as much as possible. The catch is I want a sub thats going to be much more musical than the Ultra is, more like the MK's. I know its difficult but I'm going to enjoy trying.

Any input from the experts is greatly apreciated guys.

Cheers
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if the amp is external then definately go with the behringer imo.. http://www.thomann.de/gb/power_amplifiers.html have some good amps also.

Also drivers.. have you considered (do you have the space for IB).. either way take a look at bladeice.co.uk for drivers - they hold the FI range.

Stuffing - i think 10% is optimal for most applications.

Bracing - every foot or so if possible with a different material to the main skin
I'll admit I'm not to familiar with push/pull designs. Was the cabinet size recommended by someone?
The cabinet size was calculated in Win ISD. Between 120-150 litres seems optimal. Thanks to gary for the amps, I'll take a look, cheers.
Ok, I was confusing push/pull with isobaric. Your box size is correct for this application which in reality is 2 subs in a sealed enclosure.
Push/pull is really classed as compound not isobaric, but the calcs are the same as far as I'm aware.
Re: New diy sub

Anyone got any thoughts on a dual 15" design in an 150 litre box and in a push/pull alignment, with around 1000 watts per driver. FYI the drivers are Acoustic Elegance AV15-X's and the amp a Behringer EP 4000.
It models well, with 2000 watts input a Hi-Pass filter is not required. With room gain you can expect 116 db at 20 hz.

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Mike, if I model the AV15-X in a 1 pair isobaric(compound) configuration in WinISD alpha I get a completely different result. I'm getting 106dB at 20hz. Did I mess something up?
You should get a different result. The above modeling was non isobaric which is double the Vas. True isobaric would be half the Vas.
Moonfly, do you have a link to the type of design you are thinking about?
There is an example of the push pull MK make here:

http://www.mksoundsystem.com/MK%20Leaflets/MK950Series_leaflet.pdf

The model I hope to copy is the MX250 shown here, but with more power and larger drivers for extra power and depth. I'm not as concerned with spl, but I do hope to at least match that of the SVS PB13U I sold to start this project. For clarification, this is how this design works:



The other design that has caught my attention is that of the Seaton Submersive. Its a dual opposed driver alignment. The reason I fancy the MK design is simple, I heard no other sub sound as good as the MX series. If though, there is no audible superiority between the 2 using the components Ive chosen, then the one that gives greatest depth and output will be the chosen winner.

What do you think?

EDIT: FYI, the drivers are the AE AV15-X's (on order) and the amp is a Behringer EP4000 (already purchased).
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Isobaric is modeled with 1/2 the Vas, dual opposed is modeled with twice the Vas and I think push pull is also twice the Vas. I'll ask a couple of people to make sure before we go any further.
Cheers Mike,

The push pull requires twice the Vas as well. Its actually a compound alignment, not isobaric. The reason I'm asking you these questions though is that I was using Win ISD on a borrowed laptop as the power chord failed on mine. Now I have mine back Ive installed the program and put the AE driver details back in, but the projection seems different to what it was previously using the exact same figures. I'm trying to figure out which is correct.
Neither the Seaton nor the MK is isobaric. Simple compound, twice-the-Vas proposition.

Heard some M&K subs quite a while ago, like 15 years or so. While definitely decent for consumer-level, nothing special compared to other high-end or good pro subs at the time. IMO, while push-pull may have made some sense for the limited-xmax drivers that were available when it was first marketed, now it's likely more a marketing differentiator than anything else. For DIY, wouldn't bother with it. Remember: it can only cancel out driver-related even harmonics, if that, and exposes more motor noise. And results in exposed motor and/or more complicated cabinetry. Seaton's Submersive is far more elegant, and the one I'd copy if I were to plan a sub now...

And I really like the AE drivers. The other to consider would be the Exodus Maelstrom-X, but not sure on availability for you.
Moonfly, upload your WinISD file. Let's make sure we're both on the same page so to speak.
How do I do that, do you mean upload the saved project file, or just the driver file? Where and how is best to do that?
Neither the Seaton nor the MK is isobaric. Simple compound, twice-the-Vas proposition.

Heard some M&K subs quite a while ago, like 15 years or so. While definitely decent for consumer-level, nothing special compared to other high-end or good pro subs at the time. IMO, while push-pull may have made some sense for the limited-xmax drivers that were available when it was first marketed, now it's likely more a marketing differentiator than anything else. For DIY, wouldn't bother with it. Remember: it can only cancel out driver-related even harmonics, if that, and exposes more motor noise. And results in exposed motor and/or more complicated cabinetry. Seaton's Submersive is far more elegant, and the one I'd copy if I were to plan a sub now...

And I really like the AE drivers. The other to consider would be the Exodus Maelstrom-X, but not sure on availability for you.
Compound and Isobaric appear under the same option in the pro version of ISD.
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Here's the driver file:

View attachment AE Speakers AV15-X.wdr

And here is what I came up with. 150 liters gives a Qtc of .701. Input power is 2000 watts.

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