My DIY sub setup: Opinions?

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bcool

Audiophyte
I've been shopping around for a while now and i think i have everything picked out. I just want something that will give me some good shelf rattling action in movies with a low frequency response along with good musical capabilities. Heres the list

Diamond Audio D312D4 12"
Driver:
http://www.diamondaudio.com/content/view/134/148/

Amp plate:
Bahs 500W rms
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=300-752

4" Port tube:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-352

I hope those parts express links work for you.

Anyways, I'm pretty much just decided on a ported enclosure. No baffling or insulation should be required for this setup in that case. Any opinions/comments before i start purchasing?
 
Gimpy Ric

Gimpy Ric

Moderator
Start doing your homework on ported sub enclosures first. Hsu Research, a very well respected subwoofer and now speaker company was started by Dr. Hsu, Phd. in Engineering from MIT. He knows a thing or two about porting.

The size and length of your port is going to tune the enclosure. I'd suggest a SPL meter from rat shack, and a low frequency test CD.

Anyways, if done right, you'll really enjoy the satisfaction of building your own sub. Another idea is to visit a local car stereo company that builds their own boxes, just for ideas.

Have Fun :)
 
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billnchristy

Senior Audioholic
1) Why do you think you dont need any bracing or insulation because it is a ported design?

Both are very important to any design.

2) Do you have design software? How are you planning on determining the correct box and port size?

Dont let me discourage you because it is very fun and educational, but it is not just slap a box together, put a port in and rock and roll either.
 
B

bcool

Audiophyte
I was going to build the box to the recommended enclosure size listed on the diamond spec sheet. It also calls for a 4" port that is 8" long. I know that this isn't as "slap together" as i probably made it sound. My friend who does car audio setups suggested that i not use baffling and insulation. I know that i shouldn't take his opinion on this as gold. So, basically at this point i'm just looking for opinions and resources on the matter.
 
B

billnchristy

Senior Audioholic
How big is the enclosure, I wouldnt brace a small box because its probably redundant, but a large box will definitely flex if provoked with 500w.

As for insulation, poly fill may not be necessary but it might be a nice idea to damp the enclosure on the inside with something.
 
Sheep

Sheep

Audioholic Warlord
I was going to build the box to the recommended enclosure size listed on the diamond spec sheet. It also calls for a 4" port that is 8" long. I know that this isn't as "slap together" as i probably made it sound. My friend who does car audio setups suggested that i not use baffling and insulation. I know that i shouldn't take his opinion on this as gold. So, basically at this point i'm just looking for opinions and resources on the matter.
There's your problem. Home Audio is much different, and having this sub play well in a room will be very different.

I suggest downloading a freeware program called WinISD and inputing your drivers T/S parameters into it and design a box that suites your needs (IE: Sound preference). A 4inch port that is 8inches long isn't going to give you ANY low end. I'm in the proses of building a HT sub using an infinity Kappa Perfect 10.1 driver. In my 2.0 cu ft(net) box a 4inch port, 8inches will give me a tuning of 39Hz, and the plot will be +6dB at 42hz, and -20dB and 20Hz. My original setup with a 25hz tune uses 2 12inch long 2inch diameter ports. and it's -.75 at 30hz, and -3dB 23Hz.

You may need to do a bit of designing before you settle with that your "friend" said.

SheepStar
 
jinjuku

jinjuku

Moderator
It looks like the speaker company you are looking at is primarily targeted at car audio.

What made you go with them vs. a place with more of a home audio offering, or at least some experience. Outfits like Rythmik Audio, TC Sounds, and Dayton all offer product for the home along with staff that understands home applications of their solutions.

Does Diamond?
 
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annunaki

annunaki

Moderator
There may be no problem using the driver in question. The big issue will be the enclosure. Car audio woofers and "recommended" enclosures are designed for small, confined space enviroments such as an automobile. In those confined areas you get an extremely large low end boost usually called transfer function in car audio terms. You can get by with a smaller higher tuned enclosure because of this. In the home audio enviroment, one must plan the enclosure as if they will get no room gain (transfer function) at all. I would do like suggested earlier and plot out the subwoofer's parameters in WinISD. You will want to tune the subwoofer as low as possible yet staying within it's tolorances.

If you need to post the T/S parameters for the woofer in question and maybe one of us can run it for you to get an idea on enclosure size and proper porting dimensions.
 
B

billnchristy

Senior Audioholic
A 4inch port that is 8inches long isn't going to give you ANY low end.
You cant say that without knowing the T/S specs of the driver or the box size.
 
annunaki

annunaki

Moderator
You cant say that without knowing the T/S specs of the driver or the box size.
Unless it is 6ft^3 box (or close to that) it is a pretty safe bet that it will not play much below 40hz-35hz. The T/S specs do not dictate tuning frequency of the enclosure. They (T/S) may have bearing on "what" frequency you tune. Enclosure volume, port opening surface area, and length are the determining factors for tuning frequency.
 
annunaki

annunaki

Moderator
I plotted the woofer in question on WinISD. It really is not much of a ported enclosure sub. However it can be done. A 5.0ft^3 enclosure with a 4" port 8.16" in length will tune to 24hz. You WILL need a parametric eq though to balance the response. You will need a -1.5db cut at 24hz with a "Q" of 4.00 and a .5db boost at 30hz with a "Q" of 4.00. You may be able to get away with an eq, but it would be recommended.

A lower tuning frequency really will not work without extensive eq correction.
 
D

dem beats

Senior Audioholic
I commend Anu for ending what was turning into some poor guy roasting on an open flame.

I would give you a Green chick if I could figure out how.


The only thing I can say is find a differen't driver. You want something with a much lower hz. Someone menntioned TC sounds, whom I would recomend.... I wouldn't ever call them an HT sub company however... They are and will be car audio bread and butter... but the guys there know their stuff for us HT guys they also make some verry nice passive radiators. I think you could ger a sub and a PR direct for the same as a high end diamond. You will also be much much more satisfied.
 
annunaki

annunaki

Moderator
Dem Beats,

To add a chicklet in anyone's reputation simply click on the "scales" in their post.
 
annunaki

annunaki

Moderator
bcool,

What type of budget are you on for the subwoofer? There are many good DIY options for subs that will perform better than the Diamond D312D4. Depending upon your budget I can make a few recommendations.
 
B

bcool

Audiophyte
Sorry, i've been pretty busy the last day or so. I was planning on around 200-300 for the driver, amp, and port materials. Pretty much everything except box making materials. I see a lot of good points in here about the setup and I thank everyone for their input/help. I knew in the back of my mind that i may have to go with a different driver for this application. I'd just like to get a setup that will put me into the mid 20hz range, play well musically, and be able to shake things off the shelf. I'm a lost sheep when it comes to this area so i thank you all for putting up with my noobness.
 
Sheep

Sheep

Audioholic Warlord
Sorry, i've been pretty busy the last day or so. I was planning on around 200-300 for the driver, amp, and port materials. Pretty much everything except box making materials. I see a lot of good points in here about the setup and I thank everyone for their input/help. I knew in the back of my mind that i may have to go with a different driver for this application. I'd just like to get a setup that will put me into the mid 20hz range, play well musically, and be able to shake things off the shelf. I'm a lost sheep when it comes to this area so i thank you all for putting up with my noobness.
You don't have to go with a different drive per see, but you'll need to change your box and port spec.

Annunaki, since you've already got the driver T/S in WinISD, just design the best box you can for him and give him the low down, yo.

SheepStar
 
D

dem beats

Senior Audioholic
Sorry, i've been pretty busy the last day or so. I was planning on around 200-300 for the driver, amp, and port materials. Pretty much everything except box making materials. I see a lot of good points in here about the setup and I thank everyone for their input/help. I knew in the back of my mind that i may have to go with a different driver for this application. I'd just like to get a setup that will put me into the mid 20hz range, play well musically, and be able to shake things off the shelf. I'm a lost sheep when it comes to this area so i thank you all for putting up with my noobness.
the under 20 hz realm is digging pretty deep. To get there I would recomend going with a nice big fat 18".

You will get there and 18"'s now can stay pretty clean

just my .02.
 
annunaki

annunaki

Moderator
You don't have to go with a different drive per see, but you'll need to change your box and port spec.

Annunaki, since you've already got the driver T/S in WinISD, just design the best box you can for him and give him the low down, yo.

SheepStar
24hz is the lowest tuning option before extensive eq is/would be necessary to tailor response. I honestly suggest a different driver for lower response. I played with it quite a bit. With an Fs of 40hz it truly is a subwoofer that relies on confined spaces. It might do well for PA type systems where lowend response is not quite so necessary.
 
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annunaki

annunaki

Moderator
I will have to model it, but I am thinking you may do well with the Dayton Quattro QT385-4 15" subwoofer in a low tuned vented enclosure. It is pretty cheap too around $87.00 If I get some time I can run it through WinISD and get an idea on enclosure and response. I will also look into the Dayton DVC385-88. It goes for about $128.00

For 12" subs there is the Dayton RSS315HF-4 at $130.00 This may reach into the teens with the right enclosure, but again, I will have to model it.

The 300 watt Bash amplifier is on sale at $109.00
For a bit more you could do a 500 watt BASH amplifier at $159.00 .

In a ported enclosure, the sub will be very efficient and not require a lot of power.

Most of these combinations should allow you to stay within the top end of your budget of $300. It gives you some room for enclosure supplies as well.
 
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