Need help with box specs for a certain subwoofer

[slayer]

I was hoping someone could run the theil small parameters of my sub through their program to tell me what the proper volume enclosure would be for it. I will email the specs of the sub when I get a response. It is a 15" Diamond Audio TDX subwoofer. Dual 2 ohm model. I will be running it in series for a 4 ohm load. I sell Velodyne subwoofers and used my connection to get one of their 1000w SPL-R plate amps. I also have one of the SMS-1's to help dial it in when finished. Any help would be great. Thanks.

[Dennis H]

http://www.linearteam.dk/default.aspx?pageid=newdriver

[slayer]

That didn't seem to work for me. Anyone have a high tech program they use?

[slayer]

Here is a link to the specs of the sub. It is the TDX 15/ D2 model on the chart. I want a sealed enclosure. Thanks.

http://www.diamondaudio.com/products/pdfs/TDXmanual_rev2.pdf

[Jack Gilvey]

That didn't seem to work for me. Anyone have a high tech program they use?

Not sure if it's higher-tech than Dennis' (which worked fine for me), but you can try this:

http://home20.inet.tele.dk/kou/ubmodel.html

~79L sealed given the lowest, flattest response.

[ThomasW]

That didn't seem to work for me. Anyone have a high tech program they use?

Yep and they're free for anyone to use. WinISP Pro or Unibox

[slayer]

Did you run the specs to get 79L? What is that in cubic feet? What did the respose look like?

[Jack Gilvey]

Did you run the specs to get 79L? What is that in cubic feet? What did the respose look like?

I ran them using that WinISD online calc and it gave me 79l for a maximally flat, 0.7 FR.
Running them in Unibox gives me a different Qts than that .pdf lists, though, and the box I get for the lowest F3 in Unibox is only ~1.5 ft^3. F3/Fc is about 40Hz in that size with some stuffing, but it's really inefficient. Here's what it looks like with 1000 watts:

[jonathanb3478]

What is that in cubic feet?

'bout 2.79 cu ft

[Dennis H]

A cool new Google feature is their built-in units converter. Use the keyword "in". "79 liters in cubic feet". I haven't found any units it doesn't know so far. It even translated furlongs per fortnight into miles per hour.

[ThomasW]

It even translated furlongs per fortnight into miles per hour.

This is great news, you don't know how many sleepless nights I've spent trying to figure that exact conversion....... :B

[Amphiprion]

It even translated furlongs per fortnight into miles per hour.

What about rods to the hogshead?

[Dennis H]

Sorry, it couldn't do that one. However, it told me that 1 cubic rod = 533.387753 hogshead. :B

[Amphiprion]

We need to get them to add that one, it was referenced by "Grampa" in one episode of the Simpsons as his preferred measure of fuel economy

[slayer]

It's hard to tell from that graph where it's starting to drop.
Looks like it rolls off in the lower end too quickly. Is this a problem with this sub or the fact it's a sealed enclosure?
Or does that look like a good response. I want a good all around sub for music and theater. So I will need it to play low for the theater use.
This sub was designed for car audio so I wonder if it is just not fit for this kind of use. Should I go with something else? I already built the box and am just finishing it up. I went with a 2.9 cubic foot enclosure. I had been talking with the tech department from Diamond Audio and he reccommended 2.75-3 cubic feet. I was just posting here to see if was correct. Does the response look like it will be good?

[Scott Simonian]

"In Soviet Russia, car drives YOU!"

[Dennis H]

Ah, sorry Mark, I misunderstood. Google lets us know that:

1 rod per hogshead = 4.96031746 × 10-5 miles per gallon.

Fun with science.

[mmoeller]

Does this type of speaker with a fairly high Bl and Xmax take alot of power to drive in a sealed enclosure by design? I have been following the threads for the TC Sounds TC-3000 and 2000 and they seem very similar. Although the TC speakers seem to simulate a bit more SPL for a given power, they have the same type of low end roll off as the Diamond 15. Vented versions will stay flat longer, but will roll off even faster. Am I correct in my assumptions?

[Jack Gilvey]

This sub was designed for car audio so I wonder if it is just not fit for this kind of use. Should I go with something else? I already built the box and am just finishing it up. I went with a 2.9 cubic foot enclosure. I had been talking with the tech department from Diamond Audio and he reccommended 2.75-3 cubic feet. I was just posting here to see if was correct. Does the response look like it will be good?

Going to 3ft^3 does increase the deep bass efficiency somewhat, and gives a less steep rolloff. Looks pretty good in that box with 1000 watts, although still pretty insensitive on the whole. It's basically a car driver, designed for small boxes and lots of power. Looks decent, though, if you get it and the amp for a good price.

[slayer]

Thanks for the help. I already have both and the box done. I am just wrapping up the finish on it. I used 1.5" & 1" MDF for the building material. All walls are 2 layers of the 1.5" and the baffle has an axtra layer of the 1". I used the 1" for bracing. Then coated the entire inside walls with a flexable caulk for deadening. I loosly filled it with poly fiberfill before mounting the driver. The amp sits on it's own. I figure a crown or something down the road would be a better choice. Not sure if the Velodyne puts out what it claims. 1000w rms / 2000w peak
I will try to get some pics of the finished sub up soon. Not sure how to though.

[Jack Gilvey]

Sounds like it'll be a great sub, enjoy. The only remaining question is any EQ present in the Velodyne amp, which can radically change the response . What sub is it intended for?

[slayer]

I have the Velodyne SMS-1 to handle all the EQ, X-Over, Phase..........

[Jack Gilvey]

I have the Velodyne SMS-1 to handle all the EQ, X-Over, Phase..........

Great piece. The reason I asked about the amp is that they amps intended for specific commercial subs almost always have a built-in infrasonic/rumble filter designed to protect the driver. The can roll off the bottom end quite a bit. Any idea which sub yours is used in?

[slayer]

Yes, it is the same amp used in the SPL-1200 sub. So it would be the 12" SPL sub they use.

[Jack Gilvey]

I guess your best bet is to build it and give it a whirl...I don't know what kind of circuitry might be built into that one.

[slayer]

I'm not aware of any subsonic filter in that amp. If there is one, I would guess it would be below where this sub design already begins to roll off anyways.
If I can't get the low output I want from it, I will just build another sub just for that and add it to the room. The Earthquake Supernova MKV is a sub that plays very low so I could just build one like that. Or try a tube type I keep seeing on here.

[ThomasW]

It's not unusual for there to be custom circuitry in mfgr's plate amps at are EQ'ed for their drivers...

[slayer]

It's a temp anyway. I plan on getting a good amp down the road. The sub is a dual 2ohm VC so a good 2 channel amp should push it well. This will also get me the most out of whatever amp I decide to use. We will see how it works.

[slayer]

I keep reading where Serenity & War of the Worlds has serious Bass below 20Hz. Anyone know if this is the case? I have played both and they both dominated my room with vibration. The sub handled it fine. It was seriously moving during the opening of Serenity though. It did not bottom out though. I have played a couple Bass CD's designed for car audio systems to test it out. One of the tracks plays sweeps from 30hz to 10hz and warns to turn down the volume. At the low point, the sub is moving with no noise yet my windows of the house shake violently. Very cool to feel the bass when you can't hear it. Anyone know what frequencies these movies contain so I know what my sub is playing?

[Jack Gilvey]

I doubt bottoming would be something you'd have to worry about with that driver/box combo given how much power it takes to get it anywhere near Xmax, especially if there's filtering present (likely the case). Getting through a passage without bottoming doesn't tell you what the sub is actually doing, though...can't the SMS-1 show your FR, how deep the sub is going? Here's a page with individual tones you can burn:

http://www.realtraps.com/test-cd.htm

This thread has waterfall plots of lots of movies that show their LF content:

http://www.hometheaterforum.com/htf/showthread.php?t=130032