How would i do this? JL 10w7 - Page 2 - AVS Forum
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post #31 of 45 Old 03-07-2013, 04:26 PM
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"BTW, the sub is rated for 750w and each channel of the crown is putting out 775w at 4ohms so it should be a perfect match but it doesn't seem like it's working the sub all the way."

is the content on the test disc at -0dbfs or something much lower?

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post #32 of 45 Old 03-07-2013, 06:11 PM
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LTD02,

The sub sweep was from my AIX Records Audio Calibration Disc that came with my OPPO BDP-83. On the screen it says that it's a pure sine wave that rises slowly from 16Hz to 120Hz. On the back of the blu-ray case it says that it's a 96 kHz/24-bit/5.1 LPCM test tone. I'll create a -0dbfs sine wave from 15-120Hz in NCH tone generator and test that out to compare. Today, I tested a 320kbps mp3 file of Bass I Love you that I played at -8 on my onkyo processor and it was able to get the foam surround to move ~10mm. My wife was in the kitchen and she said that the windows were rattling. I told her to come and sit next to me as the feeling was insane for a pair of 10" subs as it felt like they were moving the whole floor. I'll have to invite my neighbor who lives underneath me over to experience it in person as I know that he hears it on his ceiling. smile.gif


BTW, am I measuring the XMAX properly by measuring how far the foam surround moves out compared to when it's at rest? Maybe I'll create a 30Hz sine wave and test that since that's where my XMAX is supposed occur.


00cbirdw,

I'm not sure what you're trying to do as it looks like you're trying to mount a preamp and amp in the box???
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post #33 of 45 Old 03-07-2013, 06:44 PM
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Yeah, that was if I was going to get the Def Tech plate amp......which right now I'm leaning more towards. The amp/pre-amp assembly would only cost me $250, while the INUKE 3000 DSP would cost me at least $300 plus figuring out where to put it in my AV center. Those drawings are just a section cut both ways through the box.
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post #34 of 45 Old 03-07-2013, 08:00 PM
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Yes, I saw that. I think that you're making a big mistake as I told you earlier you could get an INUKE DSP that would be waaaayyyyy better. Why would you go with a Def Tech as opposed to something else like a 1000 watt Dayton Plate amp which will have a much lower HPF? Parts express has a bunch of different plate amps that you can choose from. That Def Tech plate amp has a high HPF (I believe that 40Hz was the lowest that I saw on that) which will suck for HT applications. Plus it can only power one sub!!! If you get the INUKE it's a 2 channel amp so you'll have an extra channel left over. You'd have to buy two Def Tech subs which will cost you $500 (as per your price that you told me) while the INUKE costs $360.

Here's the INUKE 3000DSP for $360 shipped:

http://www.zzounds.com/item--BEHNU3000DSP

Part Express plate amps:

http://www.parts-express.com/cat/subwoofer-plate-amplifiers/332



I modeled your box which doesn't account for any bracing but it doesn't matter anyway as it's no good anyway. From what I gathered your box is 21.75"x22.5"x34.5" with a slot port of 34.5"(wide)x4.75"(high)x33.25"(length). Available volume after port and sub is 6.53 cubic feet which is more than enough room but your port isn't long enough.

Here's your box in red with 775 watts!!! eek.gif Lets just say that isn't good. If you keep that box size and go with a port that's 4"x10"x38" (17Hz port tune) and put 500 watts into it with a 16Hz 3rd order HPF you'll get what's in orange. Mine box with 775 watts in in pink.



The orange isn't bad as you gain a litle bit of low end but you're also loosing 3dB (half as loud) from 20Hz and up so the little bit of low end extension doesn't make up for the loss in decibals from 20Hz and up in my eyes. Also, there's not many dsp's or plate amps have a HPF that low. The MiniDSP can do it though. I'm telling you that a 4.52 cubic foot box tuned to 21Hz with ~775 watts is best for this sub as it has a flat frequency which the orange graph does not.
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post #35 of 45 Old 03-07-2013, 08:37 PM
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there is one of those supercube amps on ebay right now for $150.

it likely has eq for the sealed supercube enclosure.

that eq is an unknown and will not be compatible with a ported enclosure.

the amplifier is also an oem, which means it was designed to work with some driver.

we do not know what the resistance of that driver was.

the amp may be compatible with your jl woofer, but without knowing, it is impossible to recommend.

hooking up a driver with too low of an impedance can burn out the amp.

audiophile, the reason he wants to use the supercube amp is that will match all his other deftech gear and because it appears to be a simple solution.

without knowing some details mentioned above, this build will be a crapshoot.

good luck, god speed, may the force be with you...i hope it all works as you hope.

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post #36 of 45 Old 03-07-2013, 08:44 PM
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LTD02, i couldn't have said it better... Can you answer my question regarding measuring xmax via the foam surround in post 32. Is this how you're supposed to measure it? Tomorrow, i'll playback some -0dbfs sine waves with my onkyo at 0dB.
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post #37 of 45 Old 03-07-2013, 09:37 PM
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Quote:
Originally Posted by Audiophile1178 View Post

The orange isn't bad as you gain a litle bit of low end but you're also loosing 3dB (half as loud) from 20Hz and up so the little bit of low end extension doesn't make up for the loss in decibals from 20Hz and up in my eyes. Also, there's not many dsp's or plate amps have a HPF that low. The MiniDSP can do it though. I'm telling you that a 4.52 cubic foot box tuned to 21Hz with ~775 watts is best for this sub as it has a flat frequency which the orange graph does not.

Yeah, I'm just being a cheap skate looking for a simple solution like LTD02 stated. I'm cool with my system as it is for now (I'm actually looking into upgrading to the BP30 fronts and a CLR2000 center), but I'll seriously look into that INUKE when I get closer to making a decision......you guys DEFINITELY know your stuff & I'd be retarded to disregard your advice, especially considering you have this sub in a box that clearly works good!!! Anyways, thank you SOOOOOO much for your helpful advice and guidance, and as I get closer to building this thing I'm sure I'll be hitting you up for more pointers LOL biggrin.gif
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post #38 of 45 Old 03-07-2013, 09:55 PM
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"Can you answer my question regarding measuring xmax via the foam surround in post 32."

sorry about that. i actually tried to find the page on the linkwitz site where he shows a clever way to do it by attaching a piece of paper to the cone, but i couldn't find it right away. xmax is from the cone, not the surround. measuring the movement of the surround will about half what the cone (and coil) are doing.

"Tomorrow, i'll playback some -0dbfs sine waves with my onkyo at 0dB."

be sure to start low and work your way up in power. :-0

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post #39 of 45 Old 03-07-2013, 10:19 PM
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Quote:
Originally Posted by LTD02 View Post

"Can you answer my question regarding measuring xmax via the foam surround in post 32."

sorry about that. i actually tried to find the page on the linkwitz site where he shows a clever way to do it by attaching a piece of paper to the cone, but i couldn't find it right away. xmax is from the cone, not the surround. measuring the movement of the surround will about half what the cone (and coil) are doing.

Yeah, I remember seeing that somewhere on here during my many many many hours that I've spent in this forum but I couldn't remember if it was the cone movement or the surround. I figured that it'd be pretty hard to measure the center of the cone as it concaves inward. I just wish I had a house like a lot of you so that way I could build some crazy stuff as I'm a bass head as well and would love to feel the single digits. Maybe, i'll be able to be at gorillas next meet. Then again it might be a bad idea as it'll show how weak my system is... tongue.gif


Quote:
Originally Posted by LTD02 View Post

"Tomorrow, i'll playback some -0dbfs sine waves with my onkyo at 0dB."

be sure to start low and work your way up in power. :-0

Will do... I'll start at -10dB on my onkyo with the sub channel at 0 (as it's currently at 4dB hot) and my crown pots at 3 o'clock. I'd like to think that i'm pretty well educated on this by now thanks to all the reading that i've done here.
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post #40 of 45 Old 03-07-2013, 10:53 PM
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ha! found it.

http://www.linkwitzlab.com/faq.htm#Q29

question 29: how to measure xmax of driver with link to wedge micrometer.

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post #41 of 45 Old 03-07-2013, 11:16 PM
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Wait... Wouldn't that be measuring total cone movement as I guess you're supposed to read it while playing a sine wave? I believe that it's called xmech.

Thanks for the info... Although, I thought that I saw pictures on this forum regarding others doing it as the link gives a good description on how to make it but i'm a little foggy on how to read the results. What I did before was put my finger just close enough to where the foam surround would touch it and then measured the distance from my finger to the foam surround at rest. Since I don't have a dust cap on my sub I'll have to see what I can do.

It's 2:15am here and i'm going to bed... smile.gif
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post #42 of 45 Old 03-08-2013, 08:05 AM
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Hey Audiophile,
I was just curious how your port is set up on your boxes? I was just wondering how you get the 4"x10"x48" port in a 2'x2' area? Does the port wrap around the inside of the box?
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post #43 of 45 Old 03-08-2013, 11:19 AM
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Hey Audiophile, I forgot I also have an old Carver m-1.5t 2 channel amplifier thats been sitting in my closet forever. Not sure if that would do the trick for a sub, or if I would still need to get a DSP and high pass filter for it also?
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post #44 of 45 Old 03-08-2013, 11:50 AM
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I wouldn't chance it as it's basically an 8 ohm amp which looks like it could also do 4 ohms but only at 400w. That's like me connecting my subs to my Rotel RMB-1095. It might work but is it worth the chance of blowing the amp up. Plus, you'd be under powering the sub as you'd only be giving it half the power. What you can do is if the carver amp works you can sell it on eBay for around $300-$500 and that would essentially cover most or all of the cost of a new amp for your sub. BTW, a DSP will have a HPF option in it, as well as, EQ settings.

Regarding the port, I think I'm going to work on the thread now so you'll see the port shortly. It's going to take some time as I have to upload the pics to photobucket and choose/photoshop what I want.
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post #45 of 45 Old 03-08-2013, 12:30 PM
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I gotcha. As I'm sure you can tell, I really am oblivious to all the innerworkings of amplifiers and the real nitty-gritty of home theater aspects!!! I may try to do that with the amp.....I know they're good amps and people speak highly of them so hopefully I can sell it for a decent price......I may actually hang on to it if I end up upgrading my front speakers to BP30's in the near future biggrin.gif I'm actually trying to do that right now, so if you know of anyone looking for some BP10B's or a ProCenter2000, here's a link to my classifieds thread: http://www.avsforum.com/t/1462168/definitive-technology-bp10bs-procenter2000-3-weeks-old#post_23057388

Thanks again for all of your help Audiophile, I REALLY appreciate it!
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