Help me build my sub

[petethekiller]

Hey guys,


I just took delivery of a Dayton 500w plate amp, 2 Dayton RSS315HF-4 12" Reference HF 4 Ohm drivers and a 3/4 inch sheet of mdf....

I want to build a sub that will serve 50% HT and 50% Music (rock and hip/hop) duty. The room it will fill will be 19x16 and by the design of the room it will be stuck in a corner.

I am open to design suggestions, IE sealed/ported but no sono tubes please. The only true restiction I have is the foot print, the foot print can be no larger than 19x19 as per the wife. Hight is not an big issue, unless we get over 45 inches.

I bought 2 drivers because, two is better than one....right? I do not need to use both but would like to find a design that could incorpirate both drives for more volume and pressure.

Please shoot me your ideas,

thanks

Pete

 

[TLS Guy]

Hey guys,


I just took delivery of a Dayton 500w plate amp, 2 Dayton RSS315HF-4 12" Reference HF 4 Ohm drivers and a 3/4 inch sheet of mdf....

I want to build a sub that will serve 50% HT and 50% Music (rock and hip/hop) duty. The room it will fill will be 19x16 and by the design of the room it will be stuck in a corner.

I am open to design suggestions, IE sealed/ported but no sono tubes please. The only true restiction I have is the foot print, the foot print can be no larger than 19x19 as per the wife. Hight is not an big issue, unless we get over 45 inches.

I bought 2 drivers because, two is better than one....right? I do not need to use both but would like to find a design that could incorpirate both drives for more volume and pressure.

Please shoot me your ideas,

thanks

Pete

I have done a complete model of your sub. You can download it here.

It is the last one posted. That driver is not suitable for sealed alignment. It requires a large enclosure, with a slot vent, that you will have to construct around the walls of the cabinet.

The vent is 2.5" x 9" in section. It is 37 inches long, and the port resonance is 180 Hz. If you crossover at 80 Hz or below, I don't think you will excite it.

The Box volume Vb is 5 cu.ft. Now when you add for the volume of the driver, bracing, port and amps you will end up with a total internal volume Vt, of around 5.7 cu.ft.

If you use 1.5" thickness for the speaker panel, and 0.75" for the rest, if you keep you footprint 19" X 19", then your sub will end up around 34" tall.

You need to brace everything very well. I would place some rockwool type product at least on the panel behind the driver to prevent reflection.

This should make a good sub.

If you want to use both drivers then you need to build two subs and get another amp. Those speakers are 4 ohm, which is the lowest impedance your amp will drive. If you were to put two drivers in the same enclosure, you would have to double the enclosure size, and I would have to recalculate the port. You would have to series connect the drivers to create an 8 ohm impedance and then the power delivered by your amp would be halved. So there would be no point in doing this. I would recommend you build two subs.

Good luck with your project and keep us posted.

 

[petethekiller]

Thanks, TSL...

I think I'll take your advise and build it to you specs.

Your info is great and very helpful. When you tesed this driver could you give me your thoughts on how it performed? I would just like to know if your unimpressed with it or if you thought it is a good buy for the money.

I paid $119 for each of them.

Some people say I need to use a sealed box in order for my sub to be a good performer with music...what are your thoughts on that statement?

Again thank you

 

[jcPanny]

Sub drivers

FYI,
The Infinity Kappa Perfect 12" subwoofer drivers that these DIY guys have been raving about is in the same price range as those Dayton drivers. You might consider one of those designs, there are several threads on the forum.

 

[TLS Guy]

Thanks, TSL...

I think I'll take your advise and build it to you specs.

Your info is great and very helpful. When you tesed this driver could you give me your thoughts on how it performed? I would just like to know if your unimpressed with it or if you thought it is a good buy for the money.

I paid $119 for each of them.

Some people say I need to use a sealed box in order for my sub to be a good performer with music...what are your thoughts on that statement?

Again thank you

First of all, I have never bought one of those drivers. I'm trusting that the manufacturers published specs are accurate. I modeled it from those specs.

This driver does not perform as a sub for home audio use in a sealed enclosure, so you will have to go vented. For car use it would be OK sealed, but definitely not for home audio. However as you can see in the graphs, there is minimal ripple, and the driver does not exceed xmax within its specified power range until it is below F3. The specs show that if you build this right it will be an impressive sub. It will be fine for music or HT. QL is just over 6, so the bass should be good and tight.

For subs, as long as the specs from the manufacturer are correct and there is minimal unit to unit variation, then the type of modern modeling I have used will tell you exactly what you will get if you build it properly to spec.

I tuned this for max bass extension. If you can tolerate an F3 a little above 20 Hz the enclosure could be made about a third smaller and re tuned. The only problem is though, the vent is longer and you might have trouble getting it in the enclosure.

 

[petethekiller]

Thanks again TSL,


I will build the sub based off your first model. At the moment it fits the budget. If you are willing, would you model a dual driver slot ported cabinet just for giggles. In the future, I plan to upgrade to an external amp that would better suit the drivers. I would be curious on how that might look.
As much as I would like to duplicate the same enclouser twice, I dont think I'd be able to make room for two 5 cu. ft. boxes...it would be easier to fit a tall-ish box type sub and make it look wife approving.

Again if you choose to model this, do it at your own leisure... it wont be needed anytime soon.

thank you

 

[TLS Guy]

Thanks again TSL,


I will build the sub based off your first model. At the moment it fits the budget. If you are willing, would you model a dual driver slot ported cabinet just for giggles. In the future, I plan to upgrade to an external amp that would better suit the drivers. I would be curious on how that might look.
As much as I would like to duplicate the same enclouser twice, I dont think I'd be able to make room for two 5 cu. ft. boxes...it would be easier to fit a tall-ish box type sub and make it look wife approving.

Again if you choose to model this, do it at your own leisure... it wont be needed anytime soon.

thank you

I will not model that with a 19" x 19" foot print. It will be far too tall, almost 6 ft, and you will have insurmountable problems with standing waves.

If you want a tall small foot print enclosure then you need to think about having me do a transmission line. Transmission line subs are rare birds indeed. However they are potentially the best, with greatest and smoothest support of the driver.

Those big lines at Benedict, threaten to collapse my studio floor and push out the windows, yet the drivers hardly move and the amps stay cool. The bass is natural it is unbelievable.

We have just bought a Quad four town home in Eagan MN. We are still busy getting furniture organized, but my wife wants HT here. I have a dual line sub in the planning, tuned one half octave apart, 20 and 30 Hz. The L/R mains will be tuned half an octave above that around 45 Hz. So almost all the bass below 80 Hz will be produced by speaking pipes and not the driver cones. Stay tuned!

 

[petethekiller]

TLS, I have a ?

I have a few questions if you dont mind.


In an earlier post you stated:

"The vent is 2.5" x 9" in section. It is 37 inches long, and the port resonance is 180 Hz. If you crossover at 80 Hz or below, I don't think you will excite it."

With my small polks, I need to cross at least at 100hz...If I did that are you saying I'll have port noise?

From another DIY board, members were concered with that the sub may not be very punchy in a large volume enclosure. For me, I'd rather have a punchy sub rather than hit 20hz...is there any truth to that stayment?

Once again, thank you very much

 

[TLS Guy]

I have a few questions if you dont mind.


In an earlier post you stated:

"The vent is 2.5" x 9" in section. It is 37 inches long, and the port resonance is 180 Hz. If you crossover at 80 Hz or below, I don't think you will excite it."

With my small polks, I need to cross at least at 100hz...If I did that are you saying I'll have port noise?

From another DIY board, members were concered with that the sub may not be very punchy in a large volume enclosure. For me, I'd rather have a punchy sub rather than hit 20hz...is there any truth to that stayment?

Once again, thank you very much

No, you will not have port noise. The vent air speed velocity is too low. The port is an open pipe, so if you crossover second order you will have to notch out the port resonance with the EQ on your amp. If the crossover is fourth order I think you will be OK. Do you know the crossover slope of your receiver?

The size of the enclosure has nothing to do with whether the bass is punchy or not. The size of the enclosure and tuning is a function of the moving driver mass and the compliance of the suspension. The QL of the model is fine, so don't worry about it. I have set the size for the most extended bass performance. That sub WILL give you deep bass you can feel. It will sound good on music also.

However if you want that punchy 70s sound, then you need a driver that will work in a sealed enclosure, with a total Q of 0.5. It won't be a sub though, as we know it these days. Those 70s systems started rolling off around 60 Hz and were usually 12db down by 30 Hz. A typical system then would have been an Altec Lansing Santiago, with a 15" 411-8A in a sealed enclosure. I always said the bass stopped before it got going. Hopeless for classical music, but the rock heads of the day loved that type of speaker.

 

[avaserfi]

I see there is some concern over port resonance. If port resonance is centered at 180Hz a standard 4th order crossover typically found in most receivers set at 100Hz would be more than sufficient to attenuate resonance.

Here is an indepth post on the subject showing inaudibility of port resonance at 110Hz with an 80Hz 4th order L-R crossover: http://www.hometheatershack.com/forums/107443-post39.html