VTF-15 or PB13 performance in a more WAF friendly box - AVS Forum
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post #1 of 19 Old 06-08-2014, 06:37 AM - Thread Starter
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Hi there -

Exact as the title says: I previously had the VTF 15 and loved its performance, but the size was a little much for the squaw.

If I went the DIY route, would it be possible to get VTF-15 or PB13-ultra performance in a smaller, more WAF friendly enclosure?

If so, what drivers should be used?

I am incapable of doing this myself (lack of time and skills, sadly) but want to do the research and see what a custom builder could do.

Thanks

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post #2 of 19 Old 06-08-2014, 10:39 AM
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How much smaller and what is your room size ?
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post #3 of 19 Old 06-08-2014, 11:04 AM - Thread Starter
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Room size is 35 x 20 x 8. A sectional cuts half of it off as the viewing area (see my sig below).

It doesn't have to be dramatically smaller - ideally id like to shave it down to the size of a submersive (a few inches in each dimension pretty much) I'm thinking a nice veneer in a overall smaller cabinet will make a nice WAF.

I know the room is huge, but since the vtf-15 did just fine for me, I'm hoping/thinking my goal is doable.

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post #4 of 19 Old 06-08-2014, 12:29 PM
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I had the hsu sub and the martycube crushes it but its not really smaller. If you go smaller the the cube in a ported design the tuning will go up to 24 to 25hz.
If you go sealed then you need a lot of power and a driver that can handle it. A uxl18 and a inuke3000dsp. Together those are 800 plus the cost of the box.
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post #5 of 19 Old 06-08-2014, 01:04 PM
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Quote:
Originally Posted by chalugadp View Post

I had the hsu sub and the martycube crushes it but its not really smaller. If you go smaller the the cube in a ported design the tuning will go up to 24 to 25hz.
If you go sealed then you need a lot of power and a driver that can handle it. A uxl18 and a inuke3000dsp. Together those are 800 plus the cost of the box.

That is either completely untrue or at least very inaccurate.
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post #6 of 19 Old 06-08-2014, 02:30 PM
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Mmmmm.... That is what ltd says but hey what does he know.... He just designed it. If he goes 20" cube then I would be ..... Right
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post #7 of 19 Old 06-08-2014, 02:45 PM
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"That is either completely untrue or at least very inaccurate."

the "cube" is pretty small. so going much smaller, either the port would have to lengthen quite a bit or the tuning would have to rise.

given the form factor, extending the port would be a pain, hence Donny's comment. while not technically accurate in a vacuum, it is pretty much the right way to think about it with respect to the martycube.

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post #8 of 19 Old 06-08-2014, 02:49 PM
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"If I went the DIY route, would it be possible to get VTF-15 or PB13-ultra performance in a smaller, more WAF friendly enclosure?"

the guys who designed those subs are pretty well informed, so they are not "bad" designs that can be easily optimized.

if you want to beat them, then you need something like better/more expensive drivers, better amps, or a different form factor, such as using passive radiators in place of ports.

pr's will allow for the same performance in a slightly smaller enclosure (no enclosure volume lost to ports), but with the added cost of the pr's.

if it were easy to get massive performance out of a tiny enclosure for low cost, that is what everybody would do.

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post #9 of 19 Old 06-08-2014, 03:11 PM
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Quote:
Originally Posted by LTD02 View Post

"That is either completely untrue or at least very inaccurate."

the "cube" is pretty small. so going much smaller, either the port would have to lengthen quite a bit or the tuning would have to rise.

given the form factor, extending the port would be a pain, hence Donny's comment. while not technically accurate in a vacuum, it is pretty much the right way to think about it with respect to the martycube.

I agree, you should not make the cube any smaller than it already is, but that is obviously not the point. The statement is incorrect because the way it is written it refers to any ported box that is smaller than the cube. There is absolutely no rule that says that a box smaller than the marty cube will have at tuning of at least 24Hz.
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post #10 of 19 Old 06-08-2014, 03:14 PM
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no disagreement there.

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post #11 of 19 Old 06-08-2014, 03:27 PM
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Quote:
Originally Posted by splotten View Post


I agree, you should not make the cube any smaller than it already is, but that is obviously not the point. The statement is incorrect because the way it is written it refers to any ported box that is smaller than the cube. There is absolutely no rule that says that a box smaller than the marty cube will have at tuning of at least 24Hz.

Show me a ported design smaller then 5 cuft with tuning lower
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post #12 of 19 Old 06-08-2014, 03:51 PM
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Quote:
Originally Posted by chalugadp View Post

Show me a ported design smaller then 5 cuft with tuning lower

Dont you believe me?

Here is a lab 12:



Fun fact: A JTR captivator has almost the exact same total volume as the 24 x 24 x 24 cube. It is tuned to 17.5Hz
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post #13 of 19 Old 06-08-2014, 03:54 PM
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I don't believe u. The port in the cube takes up the whole bottom and back. Show me the plans of the cap. Total port length.
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post #14 of 19 Old 06-08-2014, 04:13 PM
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Quote:
Originally Posted by chalugadp View Post

I don't believe u. The port in the cube takes up the whole bottom and back. Show me the plans of the cap. Total port length.

Are you kidding me?

http://jtrspeakers.com/home-audio/captivator-1000/

I obviously dont have the plans for the box but it really doesn't matter. You can tune the box to any frequency you like. Of course not all tunings are equally good, but that doesn't make it impossible to do so if you wish.
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post #15 of 19 Old 06-08-2014, 04:21 PM
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Yeah well how about helping someone instead of trying to point out people being wrong. If you don't have a design to help the op then your hijacking his thread. You don't have one. The dudes not interested in buying. live in your hypothetical world. A year on here and I haven't seen one diy design under 5cuft that has a successful tune under 20. Why don't you design one and then do sketchup drawing, parts list and help someone !
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post #16 of 19 Old 06-08-2014, 04:59 PM
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splotten, you cheated. :-)

the 'cube' has an 18 inch driver with 22 mm excursion and runs on 1100 watts. without increasing port velocity (i.e. keeping the port cross sectional area to 2" x 22.5" minimum), how much lower of a tuning/smaller of a cab do you think is reasonable?

taking down the size of the enclosure by 0.75 cubic feet requires an increase of port length inside to hold tuning and that requires something like 0.5 cubic feet, so the net decrease in cab volume is only about 0.25 cu. ft. but the sensitivity/performance loss is as though 0.75 were taken out of the cab. in my estimation, it is right about at the minimum as it is, without going to passive radiators of course.

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post #17 of 19 Old 06-08-2014, 05:43 PM
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Quote:
Originally Posted by LTD02 View Post

splotten, you cheated. :-)

the 'cube' has an 18 inch driver with 22 mm excursion and runs on 1100 watts. without increasing port velocity (i.e. keeping the port cross sectional area to 2" x 22.5" minimum), how much lower of a tuning/smaller of a cab do you think is reasonable?

taking down the size of the enclosure by 0.75 cubic feet requires an increase of port length inside to hold tuning and that requires something like 0.5 cubic feet, so the net decrease in cab volume is only about 0.25 cu. ft. but the sensitivity/performance loss is as though 0.75 were taken out of the cab. in my estimation, it is right about at the minimum as it is, without going to passive radiators of course.

Looks like you are the one cheating by changing the topic of the debate. The topic was not how much you can lower the tuning, in a smaller cap, while keeping the same port area and not increasing port speed, while inputting 1100 Watts...The topic was also not how much the volume of the port increases when you decrease the size of the box.

The topic was that it is simply not true that a box that is smaller than a marty cube will have a tuning of at least 24Hz. You have already agreed to this and i have supplied two examples that shows that it is in fact not true.
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post #18 of 19 Old 06-08-2014, 06:24 PM
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Read the title of the thread ... You have no solution for the op. Maybe help a couple hundred people, create tutorials that help dozens of people, give actual solutions to peoples diy issues . then come back and nitpick my help.

If your original response was ... Here is a link to a actual diy build that shows a smaller then 5 cuft ported box that meets the ops needs my response would have been thanks, I stand corrected.

My only real dislike of forum's is people saying things that they would never have the guts to say to the persons face. I am done arguing with u. Back to helping people instead of wasting time. Tomorrow I start my video help of a whole sub build. Maybe you can criticize my camera angles.
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post #19 of 19 Old 06-08-2014, 06:28 PM - Thread Starter
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Thanks for the responses...a few follow-up's

- yup. I figured that there were reasons for the selections behind the VTF-15 (and PB13). I didn't think that I would be able to reinvent the wheel and come up with the secret sauce HSU and SVS missed. BUT ets say if I wanted to do a passive radiator design with a better driver than the VTF-15 What would you think the cost and size of such a sub would be?


- re: the martycube. Can it be done with a plate amp, or is it a passive design only?

- would dual-opposed design like the submersive or psa XS30 be a good idea?


thanks

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