46241
From: Steve, [63.85.46.11]
Subject: Design help - Peerless 12" XLS (830500)
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First ever attempt to build my own home audio subwoofer and trying to design a ported enclosure around a Peerless 12” XLS 803500 [t/s to follow]. Originally looking at a 40 litre box w/3.5 - 4” port because that’s the specs Peerless used on their app data sheet. Started running in to problems because of the required port length (~22”) in relation to the box dimensions but thought I had a solution by increasing my box dimensions, using a couple of port elbows, and adding a serious amount of internal bracing in order to keep the volume at 40 litres. After finding this website, I decided to try plugging #’s into your ported.xls s/s to see what info I’d get. Now I’m really confused by some of the output or maybe I am misinterpreting. For example, it looks like it shows that I’d need a 30” long, 8.5” dia port. Well, if my math is right, the port will take up 70% of the volume of the enclosure. Also, I’m really not clear what enclosure configuration it shows to be optimum for my driver. Any guidance would be much appreciated. [Vas=139.2 lt, Qts=0.20, Fs=18.1 Hz, Dia=24.4 cm, Xmax=12.5mm]. This is going in a 12’x24’x8’(H) room and my goal is optimal sound quality more than chest thumping home theatre. Thank you. Moderated By: brian@diysubwoofers.org |
Responses:
[46244] [46247] [46245] [46246] [46255] [46243] [46242]
46244
From: norman bates, [oproxy.rockwellcollins.com]
Subject: it's worse than I thought........
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Sealed .707 (yuck) VB = 0.43 Ft3 fsb = 63.63 hz F3 = 63.64 hz max flat ported vb 0.49 ft3 f3 49.86 hz tune 36.90 hz db peak 0.01 The box is so small, forget about a port. 2 in a 1ft3 could port to 37hz but has an f3 of 50hz with a 4" near 22" long (plus or minus a couple of inchs). Lame. I hope you have not puchased the driver. Bottom line is that qts is too low to be a subwoofer. I believe it could make a good woofer though............. If you have, return it and we can recommend different driver option with prices and box sizes. Unfortunately, people just buy what they think is good yet have no idea what to do with the driver. With a qts of .2, best I'd recommend is a front bass horn (um, huge, pointless), even then it will only load to 200hz then roll. you can do a 6th order (tune low then add 6db of boost) but that is a tricky setup. But the 4" port is woefully too small. Beyond 100db it will act less and less like a ported and sound nothing like it should. 2 drivers Vb 1.37 ft3 Fsb=-5db b4 51.93 hz F3 b4 tune 66.11 hz Tuning 28.08 hz 4" Port length 28.53 " long Moderated By: brian@diysubwoofers.org |
46247
From: Steve, [99-181-42-237.lightspeed.rcsntx.sbcglobal.net]
Subject: Re: it's worse than I thought........
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Okay, I think I found another driver with numbers I like better for a ported box. Creative Sound Solutions SD12. [Re: 3.6, Le:1.45, Fs: 23.3, Qms: 2.87, Qes: 0.447, Qts: 0.387, Vas: 83.3, Cms: 0.25, SD: 490, Xmax 19.5, Xmech: 32, BL: 14.6, Mms: 186.4, SPL: 85.6] Looking at a 2.5 ft^3 box with 4" flared port. I would welcome someone taking a look and critique this driver & enclosure choice. Moderated By: brian@diysubwoofers.org |
Responses:
None
46245
From: Brian, [69.73.241.60]
Subject: Re: it's worse than I thought........
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That driver is designed to use with a passive radiator, not a port. |
46246
From: Steve, [63.85.46.11]
Subject: Re: it's worse than I thought........
| Yes, that's the way it is starting to look. So...options? Not able to find the Peerless 12" PR in stock anywhere (Madisound, PE). Could I go with 2 of the 10" PR's? My budget getting squeezed with that option and I fear that correct tuning may be out of the range of my limited abilities. Actually may be better off looking for a different driver that is more suited to a ported box. Thank you for all the responses. |
Responses:
[46255]
46255
From: djk, [65-103-50-122.cdrr.qwest.net]
Subject: 3x
| A PR needs to have about three times the Vd of the main driver, so two 12" PR or maybe an 18" PR (expensive either way). |
Responses:
None
46243
From: norman bates, [173-20-191-217.client.mchsi.com]
Subject: well, those specs are tough...............
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Qts of .2, it will be hard to get low subwoofing from that driver (un boosted). I assume the best design would be a extended bass shelf (search here) or a boosted 6th order ported. Unboosted, I'm guessing that a 2ft3 box tuned to 30hz, but it will be hard to get tuning that low in that small of a box with a 12" with 12mm Xmax without chuffing at high volume. I do know that 30hz tuning sounds much better than 40hz............ Even if a box droops from 40hz down to 30hz........... I'll crunch some numbers tomorrow and post past 8pm eastern standard time. My gut instinct says 2 drivers in a single box using a big long xmax passive radiator. Since qts in that low, sealed is out of the question, f3 would be mid 60's........... Norman Moderated By: brian@diysubwoofers.org |
Responses:
None
46242
From: andrewt, [host81-129-19-215.range81-129.btcentralplus.com]
Subject: Re: Design help - Peerless 12" XLS (830500)
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I like the way WINisd pro works and displays results. Download it (it's free) and play with sizes and ports. Remember the box volume excludes the port volume. If the port is big you have to add that big volume to your box volume to find the total volume you need to build. A smaller port area than 8.5inch diameter will do for a 12inch driver. You can probably get away with 4inch diameter. |
Responses:
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