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Post by Gary Cook on May 24, 2015 19:04:35 GMT -5
I currently use an XPA-100 as a sub woofer amp for a 17" driver in a 140 litre dual ported enclosure. Easily the best subwoofer amp I have used, including a number of pro amps from Crown and Behringer. The driver is rated at a nominal 4 ohms but has a quoted impedance range from 2 ohms to 8 ohms and the XPA-100 handles it easily. I have also tried an XPA-1L with the same sub woofer and found no audible difference.
Cheers
Gary
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Post by trevordj on May 25, 2015 2:43:30 GMT -5
Hello Keith I purchased a XPA-1 gen 2 for a subwoofer build. Will this amp be overkill or not enough power. I've noticed many of the members here building their own as well. Now that I purchased the XPA-1 I'm second guessing my amp purchase due to lack of experience with a subwoofer build. Will the XPA-1 gen2 handle the passable 2-ohm dip? Suggestions will be greatly appreciated! It depends on the subwoofer, your room, your box, and your listening preferences. If you could provide some additional details about the project it would help answer the question. |
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Post by garym on May 25, 2015 7:55:45 GMT -5
It's overkill. There is no point in buying a super clean amp to power a sub. Distortion is hard to hear below 80 Hz anyway, unless its excessive. Few sub drivers can produce a 30 Hz tone with less then 5% THD. An additional 0.1% added by the amp would be unnoticeable. I've built 3 subs, used Bash plate amps in all of them. But the PA amps are fine too.
You should buy another XPA-1 and use them to power your mains. Get a plate amp or a PA amp for the subs. Just be sure it has enough power for the driver you use.
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Post by mm on May 25, 2015 12:33:50 GMT -5
Hello Keith I purchased a XPA-1 gen 2 for a subwoofer build. Will this amp be overkill or not enough power. I've noticed many of the members here building their own as well. Now that I purchased the XPA-1 I'm second guessing my amp purchase due to lack of experience with a subwoofer build. Will the XPA-1 gen2 handle the passable 2-ohm dip? Suggestions will be greatly appreciated! PM sent. |
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Post by Gary Cook on May 25, 2015 14:56:51 GMT -5
It's overkill. There is no point in buying a super clean amp to power a sub. Distortion is hard to hear below 80 Hz anyway, unless its excessive. Few sub drivers can produce a 30 Hz tone with less then 5% THD. An additional 0.1% added by the amp would be unnoticeable. I've built 3 subs, used Bash plate amps in all of them. But the PA amps are fine too. You should buy another XPA-1 and use them to power your mains. Get a plate amp or a PA amp for the subs. Just be sure it has enough power for the driver you use. But what if the quality amp reduces the theoretical 30 Hz / 5% THD to 4% due to its control, damping factor etc? That would be worthwhile. I'm not sure which is the overkill (1 x 17" sub with an XPA-100) or (1 x 15" sub + 2 x 12" subs with 3 x plate amps)  Cheers Gary |
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Post by garym on May 25, 2015 17:39:30 GMT -5
But what if the quality amp reduces the theoretical 30 Hz / 5% THD to 4% due to its control, damping factor etc? That would be worthwhile. I'm not entirely sure, but I don't think an amp can do anything about innate distortion in a driver. Heh. The 15" is just for LFE. It reaches deeper, but not as clean as the two 12s. The 15" is not active when playing music. |
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Post by Gary Cook on May 25, 2015 18:17:13 GMT -5
But what if the quality amp reduces the theoretical 30 Hz / 5% THD to 4% due to its control, damping factor etc? That would be worthwhile. I'm not entirely sure, but I don't think an amp can do anything about innate distortion in a driver. I don't know either, but perhaps it's simply a matter of better control, higher damping factor that minimises the 2nd and 4th order (unpleasant) harmonics. Typically speaker distortion is measured at maximum SPL and I sure as hell don't run my sub anywhere near its maximum SPL. Logically its THD not going to be anywhere near 5% at my listening levels hence the amp difference is noticeable.
I was contemplating a pair of smaller subwoofers for music but, with the XPA-100 driving it, the 17" sub is so improved in clarity that there is no longer a compelling case.
Cheers Gary
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Post by mm on May 25, 2015 18:44:20 GMT -5
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Post by deltadube on May 26, 2015 0:22:02 GMT -5
It depends on the subwoofer, your room, your box, and your listening preferences. If you could provide some additional details about the project it would help answer the question. Hello, I haven't setteled on a specific woofer or size. I've found some very good pre-fab DIY enclosures. Listing preferences lower the better with quick response along high SPL for music. I do have additional Emotiva amps on hand, but I purchased a third XPA-1 gen2 for a possible sub build. I also have the XPA-2 gen2 available for use as well. I've been second guessing myself with this build and may buy PSA subwoofer, but I have amps and also have woodworking skills with hopes of building a better subwoofer than I can purchase. I'm open for recommended options for woofer brand and size. With the much valued experience here at the Lounge I should succeed. Many thanks to all input and suggestions well buy or make 2 subs eh... 2 is much smoother than one in the room!!! psa makes some nice subs for a fair price.. cheers |
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Post by trevordj on May 26, 2015 22:23:03 GMT -5
It depends on the subwoofer, your room, your box, and your listening preferences. If you could provide some additional details about the project it would help answer the question. Hello, I haven't setteled on a specific woofer or size. I've found some very good pre-fab DIY enclosures. Listing preferences lower the better with quick response along high SPL for music. I do have additional Emotiva amps on hand, but I purchased a third XPA-1 gen2 for a possible sub build. I also have the XPA-2 gen2 available for use as well. I've been second guessing myself with this build and may buy PSA subwoofer, but I have amps and also have woodworking skills with hopes of building a better subwoofer than I can purchase. I'm open for recommended options for woofer brand and size. With the much valued experience here at the Lounge I should succeed. Many thanks to all input and suggestions How big is your room (cubic feet)? Do you have a significant other who will take issue with large subwoofer boxes? What is your budget? Generally if you are looking to get ultra low frequency (ULF) output (20hz or lower), a larger box with a low tuned port is required. Alternatively large woofer(s) in large sealed boxes can get you the ULF content but you will need a high excursion, low resonant frequency (Fs) woofer (which is necessarily inefficient) with lots of power (more than an XPA-1 likely) to get there. Music is a little bit easier as it doesn't have much content below 30hz unless you are listening to some electronic music. A small room will help, but if you want to get to reference volumes below 20hz in a, say, 3500 cubic foot room you will be looking at multiple woofers and more power than an XPA-1 could provide. Reference level is damn loud though. |
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Post by Gary Cook on May 26, 2015 23:49:35 GMT -5
Generally if you are looking to get ultra low frequency (ULF) output (20hz or lower), a larger box with a low tuned port is required. Alternatively large woofer(s) in large sealed boxes can get you the ULF content but you will need a high excursion, low resonant frequency (Fs) woofer (which is necessarily inefficient) with lots of power (more than an XPA-1 likely) to get there. Music is a little bit easier as it doesn't have much content below 30hz unless you are listening to some electronic music. A small room will help, but if you want to get to reference volumes below 20hz in a, say, 3500 cubic foot room you will be looking at multiple woofers and more power than an XPA-1 could provide. Reference level is damn loud though. An XPA-1 will make more than a 1,000 watts into 4 ohms. I have a 17" driver in a 140 litre dual ported enclosure tuned for 18 hz powered by an XPA-100 (400 watts into 4 ohms) and it loosens the floor boards, rattles the walls and wakes up the neighbours easily. Plus 3,500 cubic feet is less than a third my room's size ie; it's not that big a room. Cheers Gary |
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Post by trevordj on May 27, 2015 0:25:47 GMT -5
How big is your room (cubic feet)? Do you have a significant other who will take issue with large subwoofer boxes? What is your budget? Generally if you are looking to get ultra low frequency (ULF) output (20hz or lower), a larger box with a low tuned port is required. Alternatively large woofer(s) in large sealed boxes can get you the ULF content but you will need a high excursion, low resonant frequency (Fs) woofer (which is necessarily inefficient) with lots of power (more than an XPA-1 likely) to get there. Music is a little bit easier as it doesn't have much content below 30hz unless you are listening to some electronic music. A small room will help, but if you want to get to reference volumes below 20hz in a, say, 3500 cubic foot room you will be looking at multiple woofers and more power than an XPA-1 could provide. Reference level is damn loud though. Room size = roughly 3500 cubic ft. Enclosure size = how large is needed? Budget = will be determined by DIY vs the PSA and SVS top performers cost? Sounds like I may need to sell my new XPA-1 gen 2 if it may be insufficient for powering a DIY. I've considered the PSA XS30SE, XS15se (2) or XV15se (2) as well, but would perfer to have only 1 subwoofer in my area. If I can build and perform better i would prefer the DIY. Thank you for your time and experience I don't think you necessarily need to sell your XPA-1. To get decent output in a room that size you will likely need at least two subwoofers, however. If you want reference output you would likely need 4 (or two 24 inch woofers). The good news is, by going DIY, you will pretty much always get more bass for the dollar than anything pre-made (even internet direct). The downside (for some), is you have to build it. If you want a turnkey solution the PSA woofers you mentioned above are excellent. Just to illustrate a point, here is what I would consider a few scenarios: Scenario #1 Sell the XPA-1 -$650 2 x XV15SEs (no EQ) $1800 Net cost $1150 Scenario #2 Keep the XPA-1 (already purchased) 2 x Stereo Integrity HT18s $348 2 x DIYSG 4 cubic foot flat pack $340 (assuming $100 shipping) Cabinet hardware $40 (assuming you use speakon connectors... which you should) Paint $50 Labor $0 assuming you do all the work yourself Net Cost $778 Scenario #3 Same as scenario #2 except use a Dayton UM-18 instead of the SI HT18s $560 Net Cost $990 Performance: Similar in terms of raw output in scenario 1 to 2 however the PSA edges out the SI18 when it comes to distortion. The Dayton UM-18 beats them all but will require more power to do it (and it is only available in dual 2-ohm so you would be forced to wire your xpa-1 to either 2 ohms or 8 ohms with both wired to the same channel). You could get substantially more output out of the SI HT18 but it would require ported enclosures (which will also get you some more bottom end but will increase your box size). Remember, you are comparing the PSA's ported 15 to sealed DIY 18s here. If you did either of the DIY woofers ported you would get substantially more output than the PSA but the box sizes will also be larger (especially for the UM-18). If it were me, and I already had the XPA-1 I would take advantage of the extra output from a DIY ported design and build dual SI HT-18s. Just my $0.02 |
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Post by Gary Cook on May 27, 2015 18:43:59 GMT -5
Do you feel the flatpack sub box is better than the Stonehenge. I feel better with this project thanks to your extensive and detailed advice and plan to move forward with the DIY. Thank you very much for your patience and time spent. I have found DIY'ing a subwoofer enclosure to be a rather satisfying experience, makes you feel good once it's done to be able to say to people "I made that". Plus you can then use whatever power amplifier you like. Test a few, most suppliers have trial periods, then pick the one you prefer. There is only one catch, you have to post pictures and reviews, please.  Cheers Gary |
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Post by vneal on May 27, 2015 18:58:44 GMT -5
I disagree. A quality low distortion high wattage mono amp is just what the doctor ordered for an ultimate sub woofer.
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Post by Deleted on May 27, 2015 21:58:03 GMT -5
I don't think you necessarily need to sell your XPA-1. To get decent output in a room that size you will likely need at least two subwoofers, however. If you want reference output you would likely need 4 (or two 24 inch woofers). The good news is, by going DIY, you will pretty much always get more bass for the dollar than anything pre-made (even internet direct). The downside (for some), is you have to build it. If you want a turnkey solution the PSA woofers you mentioned above are excellent. Just to illustrate a point, here is what I would consider a few scenarios: Scenario #1 Sell the XPA-1 -$650 2 x XV15SEs (no EQ) $1800 Net cost $1150 Scenario #2 Keep the XPA-1 (already purchased) 2 x Stereo Integrity HT18s $348 2 x DIYSG 4 cubic foot flat pack $340 (assuming $100 shipping) Cabinet hardware $40 (assuming you use speakon connectors... which you should) Paint $50 Labor $0 assuming you do all the work yourself Net Cost $778 Scenario #3 Same as scenario #2 except use a Dayton UM-18 instead of the SI HT18s $560 Net Cost $990 Performance: Similar in terms of raw output in scenario 1 to 2 however the PSA edges out the SI18 when it comes to distortion. The Dayton UM-18 beats them all but will require more power to do it (and it is only available in dual 2-ohm so you would be forced to wire your xpa-1 to either 2 ohms or 8 ohms with both wired to the same channel). You could get substantially more output out of the SI HT18 but it would require ported enclosures (which will also get you some more bottom end but will increase your box size). Remember, you are comparing the PSA's ported 15 to sealed DIY 18s here. If you did either of the DIY woofers ported you would get substantially more output than the PSA but the box sizes will also be larger (especially for the UM-18). If it were me, and I already had the XPA-1 I would take advantage of the extra output from a DIY ported design and build dual SI HT-18s. Just my $0.02 Do you feel the flatpack sub box is better than the Stonehenge. I feel better with this project thanks to your extensive and detailed advice and plan to move forward with the DIY. Thank you very much for your patience and time spent. If your set on flat packs, "I" would do the Stonehenge over a sealed 4cube. I absolutely love my ported 18's they are just as detailed and responsive as they were in sealed enclosures but with more headroom. The xpa is fine amp but power really is eaten up quick with a sub. I had NO problem clipping my ep4000 with my 18's and it's got "real world" power of about 1000watts rms per channel. I required two 18's and two 21's to reach reference CLEANLY in my 3500 cu ft room. I seldom listen that loud so can imagine how low my distortion is at "normal" listening levels. The si18 are great budget subs But have a weak motor. The ultimax is a little stronger. I have mach 5 IXL subs which are "supposed" to be between the two. I'm upgrading to UXL subs which are better than any of the mentioned above. Far stronger motor, more robust voice coil... Almost on the same level as the " king Lms ultra" and definitely comparable to the si hst sub. You could also look at the sundown zv4 drivers they are more expensive but top notch performers. I might look into building a pair of dual opposed 15" ultimax subs. They would definitely require more amp but would be totally awesome. They'd be on the same level as the seaton submersive sub. You'd be able to keep cabinet size a lot smaller bit still get great output and super low distortion. |
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Post by Deleted on May 27, 2015 22:20:53 GMT -5
Now that's one impressive DRIVER! UXL $500.00 and out of stock. Recommendations to power this BEAST? Thanks again fattykidd ] www.china-sanway.com/Product.asp?BigClassName=FP-new%20series%20Switching%20Power%20AmplifierI use the 10kq The UXL is actually up in a group buy on the "other" forum. They're 460 cdn. As another side track the ftw21 group buy should be starting up some time this summer. Now that's an impressive driver and works f'n awesome in 6cu ft... or 24"cube. Yet another option. I honestly can't think of any commercial or internet direct sub that would compare with a pair of ftw's. Where in conus are you located? I got a couple buddies that would probably be willing to help out with out of the ordinary flat packs if that was the direction you wanted to head.. |
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Post by trevordj on May 27, 2015 22:33:31 GMT -5
Do you feel the flatpack sub box is better than the Stonehenge. I feel better with this project thanks to your extensive and detailed advice and plan to move forward with the DIY. Thank you very much for your patience and time spent. The stonehenge is great but I think I recall reading that DIYSG wasn't planning on making these anymore. I might have made that up so you probably want to email Erich and see. Good luck with the build! Going the DIY route will definitely yield a sense of accomplishment. And I agree with Gary, pictures are mandatory! |
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Post by Deleted on May 27, 2015 22:37:21 GMT -5
If I remember correct it was 900 and change plus Canadian customs and taxes at my door. They are awesome for subwoofers bit need the fans swapped out unless your gear is in a separate room of course.
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Post by trevordj on May 27, 2015 22:40:11 GMT -5
If your set on flat packs, "I" would do the Stonehenge over a sealed 4cube. I agree 100%. A well done, low tuned ported enclosure is the way to go especially is you are looking for ULF output. |
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Post by vneal on May 28, 2015 7:36:13 GMT -5
I disagree. A quality low distortion high wattage mono amp is just what the doctor ordered for an ultimate sub woofer. What amplifier do you or the Doctor recommend for this project? XPA-1 gen2 not a good choice? Thank you No the XPA1 is a good choice. I disagree with the poster who thinks it is overkill. My JL Audio sub has a built in 900 watt mono amp that gets me by. I am a bit of a critic on subs in that I have only heard two brands that sound good to me- JL Audio and REL. I have owned numerous other brands |
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