wsu99999 Posted February 13, 2009 Share Posted February 13, 2009 I've just completed my first DIY subwoofer and I'm not pleased. I've clearly made a mistake somewhere and I was hoping someone on the Forum could help me make my wrong right. I've posted this on AVS, but should have came here first. I'm using a Dayton DVC (600W version) subwoofer in a sealed 18x18x12 box with dampening material and a Swan Sub250 plate amplifier. The amplifier I think is only like 100w RMS but for some reason my subwoofer keeps bottoming out at really high volumes. I thought it may be the amplifier clipping, but the people at AVS say it's the subwoofer bottoming out. The box is almost the exact dimensions Parts Express state for ideal operations, so how can a 100W amp bottom out a 600w speaker in a box built to spec? The Swan amp was temporary as I planned on purchasing a Behringer 1500 or 2500 per recomendations (which now may be overkill), and I know this isn't the best of the best subs, but it's what I have and I'm trying to find a way to make do with what I got. If I build a vented box, would this stop the woofer from bottoming out? If I purchased a Behringer, would the bottoming out be worse? From what I gather (ear, help me out), the ideal vented box for this subwoofer would be around 3.1 Cu ft and have a 4" port with around 14" length - does that sound about right? Do you have anyother designs that would work better? Thanks for your help - It is much appreciated!@ Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 13, 2009 Share Posted February 13, 2009 What model is it, the 12, or the 15"? 600 watts is it's thermal rating, but the actual amount of power you can put into it depends on the alignment of the enclosure, ( sealed vs ported ) and what the volume of it is, tuning frequency if ported. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 13, 2009 Share Posted February 13, 2009 I checked your post on the AVS forum, and grabbed the info from Parts Express. It seems as though this likes a smaller box, WinISD when I got done with entering in the parameters, it suggested a smallish box, 1.385 cu ft for a Q of .707. If the box you put it in is 18 x 18 x 12 internally that's 2.25 cu ft. Do you have a measurement of the rear enclosure on the built in amp? Driver displacement in the box is negligable, but I would account about 0.1 cu ft for driver, maybe another .2 cu ft for the amp. The simulation of a box of about 1.95 cu ft shows that with a power input of 200 watts and a moderate VC temp rise of 60 degrees C, you are getting close to the electrical xmax from 30 hz on down. IF there is ANY boost built into the amp, you could very well be bottoming it out, the suspension stretches tight at 21 mm according to the Dumax report. Maximum excursion limited output would be in the area of about 104 db @ 30hz, and around 97 db at 20 hz. Realistlically, you could benefit from a vented box, but you still can only expect so much from a single 12. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 13, 2009 Share Posted February 13, 2009 What is your target SPL @ 20 hz? With that very same driver in a 4 cubic foot box, tuned to 23 hz ( single 4" flared PSP port kit, with center tube cut down just a hair ) you will have very close to the same cone excursion down to 31 hz with a 250 watt amp. At that point, the port starts to add in it's contribution, and the driver excursion starts to drop. You gain almost 7 db at 30 hz with the ported box, and at 20 hz, you have about 4 db more than the sealed box it's currently in. Add a second Dayton DVC 12 in an identical 4 cu ft vented box, tuned to the same frequency, you would have something pretty decent, with about 116 db on tap @ 30 hz, and 108 at 20hz. In this case, the subs would need co-location. You WILL need a high pass filter, either an outboard unit like the eD eq .2 or Behringer Ultragain Mic Pro 2200. ( About $ 100 ish ) Without a proper high pass filter, the drivers WILL destroy themselves. Go easy on the throttle at first. Quote Link to comment Share on other sites More sharing options...
wsu99999 Posted February 14, 2009 Author Share Posted February 14, 2009 Thanks for all of the info, but wouldn't a box of 18x18x12's volume be around 1.6 cu ft? That's the calculation I got. So are you saying I shouldn't get a behringer amp? Would it make it bottom out more? I've always thought more watts made it cleaner. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 14, 2009 Share Posted February 14, 2009 18 x 18 x 12 INTERNAL dimentions = 3888 cubic inches, divide by 1728 to get cubic feet, in this case 2.25. If those are external dimentions, you must deduct the material thickness and also take into account if there is any bracing. Quote Link to comment Share on other sites More sharing options...
wsu99999 Posted February 14, 2009 Author Share Posted February 14, 2009 Sorry, that's external with 3/4 mdf accounted for. Quote Link to comment Share on other sites More sharing options...
wsu99999 Posted February 18, 2009 Author Share Posted February 18, 2009 OK - I'm building a ported box now for this driver and I've ordered the behringer ep2500 as well. I know the amp is overkill for a single sub, but I will add another down the road and will honestly probably get a bigger sub size too. This may be a stupid question, but can someone show me how to hook up the Behringer to my existing setup (I know I need XLR to RCA cables, but what about the speaker wire? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 18, 2009 Share Posted February 18, 2009 It's been a while since I looked at the back of my 2500 but I believe I used bare speaker wire at the terminals. Quote Link to comment Share on other sites More sharing options...
wsu99999 Posted February 18, 2009 Author Share Posted February 18, 2009 Last question - Promise!!! I'm running a Marantz 7001 and it has the "crossover" internally that only sends frequencies below "X" to the subwoofer - Since the Behringer doesn't have a low pass filter, do I need another crossover, or will my marantz take care of it? If I need a crossover, how much am I looking at and what do you guys recomend? Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 19, 2009 Share Posted February 19, 2009 No, you don't really need a crossover, but you will need a high pass filter to keep the driver from over-excursion and breaking itself. Forget the eD EQ.2 for a high pass filter if you are using a pro amp like the Behringer EP2500, it doesn't play nice. ( voltage limited ) Instead get a Behringer UltragainPRO MIC 2200: http://cgi.ebay.com/BEHRINGER-MIC2200-2-CHANNEL-LIVE-RECORDING-MIC-PRE-AMP_W0QQitemZ300294680064QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item300294680064&_trksid=p3286.c0.m14&_trkparms=72%3A1234|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A5|294%3A50 I can use a software package to measure the actual response through it as I own one, and can post the dial settings in order to optimize it to the correct setting for you. The EP2500 even in stereo is a bit much in terms of power for that driver. Do NOT try to bridge the amp, instead run the sub off of one channel of the amp in stereo mode. ( turn other channel gain control down ) There are small 'DIP' switches on the rear of the amp to set it's configuration ( stereo / mono, clip limiter, high pass frequency ), these must be set correctly, other wise the amp will not work properly. Quote Link to comment Share on other sites More sharing options...
wsu99999 Posted February 19, 2009 Author Share Posted February 19, 2009 Is the high pass filter absolutely necessacary? Is there a cheaper method? The problem is I've already reached my budget If anything, I would rather spend that money on a better speaker (and sell the dayton). Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2009 Share Posted February 19, 2009 There are small 'DIP' switches on the rear of the amp to set it's configuration ( stereo / mono, clip limiter, high pass frequency ), these must be set correctly, other wise the amp will not work properly. This is one of the most important statements in this thread and bears rereading. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2009 Share Posted February 19, 2009 Is the high pass filter absolutely necessacary? Only if you don't want to keep buying drivers. The 2500 is a brute. Quote Link to comment Share on other sites More sharing options...
wsu99999 Posted February 19, 2009 Author Share Posted February 19, 2009 Darn! I really hoped I was done. What is the absolute cheapest route I can go? I don't even know where to begin to look. I saw the one referenced above and it looked like something nasa would have in a space ship. Are there any little sister models to that one? What would the absolute rock bottom unit be that would still be f unctional? I will probably need your help setting everything up to. Thanks guys! Sorry for being such a little ***** about this, but I really don't know much about what I'm doing obviously. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 19, 2009 Share Posted February 19, 2009 "Is the high pass filter absolutely necessacary? Is there a cheapermethod? The problem is I've already reached my budget If anything,I would rather spend that money on a better speaker (and sell thedayton)." Absolutely 100% a high pass filter is needed. Is there a cheaper method.... not really, the Reckhorn B-1 is the same price. Reckhorn Quote Link to comment Share on other sites More sharing options...
wsu99999 Posted February 19, 2009 Author Share Posted February 19, 2009 Behringer DSP1124P - Dual Channel 24-Bit Feedback Suppressor/Parametric EQ Will this work? I found one local for 40 bucks. I need to act quick though. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 19, 2009 Share Posted February 19, 2009 As a high pass filter no, but it is useful as an equalization tool. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2009 Share Posted February 19, 2009 That's a parametric EQ. It's great for EQing your sub and flattening room response but it's not what you're looking for. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2009 Share Posted February 19, 2009 Michael types too fast[] Quote Link to comment Share on other sites More sharing options...
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