fleabag Posted January 18, 2018 Share Posted January 18, 2018 (edited) Rather then get rid of a huge Peavey BVX cab i have with a 15" 600 watt Fane Sovereign LF driver, and the fact that no one wants to buy this, I figured i may as well keep the driver but stuff it in a more reasonable box. The current Peavey cab which originally housed a Black Widow, is pretty big I did some measurments, turns out to be about 7.22 Cubic feet. Allowing for the fact that i measured outside edges, perhaps a bit less, say 7.0 cubic feet and this equates to about 198 litres. Now on the Fane website, they have recommendations for volume , both Cubic ft and Litres. Even the biggest at 4.41 Cubic ft / 125 litres is way smaller than the Peavey I'm not sure about their smallest recommendation of 1.76 cubic ft / 50 litres ??? They also dont mention porting / port sizes. What minimum size ported cab could i reasonably get away with in size, without killing the bottom end ? Problem 2 is the fact that i live in a flat, with nowhere to work ( no shed ) and no power tools to speak of. This means i will have to pay someone to build it From the FANE site ... Edited January 18, 2018 by fleabag Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 18, 2018 Author Share Posted January 18, 2018 (edited) PS could i get away with 12mm ply and would i get the cab out of one 8x4ft sheet Edited January 18, 2018 by fleabag Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted January 18, 2018 Share Posted January 18, 2018 Dunno. I'd suggest you have a look at some online plans for cabinet building ideas; fEARful™ enclosures for bass/drums/keys Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted January 18, 2018 Share Posted January 18, 2018 Just now, SpondonBassed said: Dunno. I'd suggest you have a look at some online plans for cabinet building ideas; fEARful™ enclosures for bass/drums/keys I'm sure someone here would build one for you for expenses. I'd even consider it myself if transport wasn't an issue. Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 18, 2018 Author Share Posted January 18, 2018 (edited) Cheers for that link - having a read right now Believe me, someone would have to build it for me for the reasons stated, and yes, coin would have to be exchanged for services rendered I'm looking at where i can buy Baltic Birch locally at the mo. Havent founds much round these here parts Edited January 18, 2018 by fleabag Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 18, 2018 Author Share Posted January 18, 2018 Well, a quick read of the possible builds means either a 15/6 ( i dont really want an extra speaker ) or a 15 sub, which is not what i'm after Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted January 18, 2018 Share Posted January 18, 2018 Your builder of choice might offer suggestions as to a modification such as leaving the surplus driver out and recalculating the overall cab volume. Also, I think you might find more stuff like that if you do a 'net search from time to time. It's an interesting project. Quote Link to comment Share on other sites More sharing options...
bertbass Posted January 18, 2018 Share Posted January 18, 2018 Why not check out Bill's Simplex designs. The plans are cheap enough. http://www.billfitzmaurice.com Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted January 18, 2018 Share Posted January 18, 2018 Firstly, both the fearful and Simplex designs are optimised for particular speakers, so they will not work as well with your drive units. Secondly, as you reduce the box size, you tend to get more boom in the sound - the response develops a peak in the 100-200 Hz range. A little of this may be to your advantage, but too much will sound bad. Given the information on the drive unit that you have from Fane, you could download a copy od 'WinISD', follow the instructions about adding that information, and let it design your own speaker box, while you adjust volume and porting see what effect it would have. David Quote Link to comment Share on other sites More sharing options...
stevie Posted January 18, 2018 Share Posted January 18, 2018 Fane have their own cabinet design, which works with the driver you have. It's also well tuned for bass guitar. It's 125 litres internal volume. You could go a bit smaller but I wouldn't suggest going below 100 litres. If you deviate from the published design, you'd have to alter the port tubes slightly. Cabinets15inch125Lres.pdf Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 18, 2018 Author Share Posted January 18, 2018 Thanks everyone - will check Bill's Simplex cabs. Had a Jack 2 x 12 in the past, very nice. I didnt build it though - bought it here on BC I've tried WinSD in the past, but not being a techie, i got confused over the graph results. When i fitted 4 Beyma SM/110's to my 2 other cabs, Stevie / Phil etc worked out all the port sizes and i ended up with a very nice pair of 2x10 cabs. I even bought the Beymas on their recommendations Stevie - those plans are for the Colossus drivers, which top out at 1.5khz , so does that mean they're more Sub than my Sovereign, which tops out at 3.5khz ? 125 litres is way better than the Peavey cab, and this is the biggest volume Fane state ( as you can see in Fanes recommendation ) and i wonder if that's because its a Sovereign, and not a Colossus, which i presume needs more low end, and therefore a bigger design ? I could be talking rubbish - i wouldnt know Quote Link to comment Share on other sites More sharing options...
stevie Posted January 18, 2018 Share Posted January 18, 2018 The size of the cabinet won't make any different to the high frequency response of the speaker. I modelled that 125-litre cabinet for the Sovereign 600 and it works fine. I wouldn't be too keen on 12mm plywood for a cabinet of that size and power. Without a lot of extra bracing, it will probably vibrate too much. You might get away with 15mm. Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 18, 2018 Author Share Posted January 18, 2018 Okey Dokey. I'm happy to go 15mm. Did your modelling include any ports ? The Colossus cab in the link looks like 4 ports @ 100mm diameter and 162mm port length Quote Link to comment Share on other sites More sharing options...
stevie Posted January 18, 2018 Share Posted January 18, 2018 Yes, they tune the cab to 50Hz, which is just right for bass guitar. Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 18, 2018 Author Share Posted January 18, 2018 (edited) Is it possible to place the 4 ports at the rear instead ? I was just thinking of the height needed to squeeze a 15 and 4 x 100mm ports in the front baffle. I dabbled with some conversion tables to get roughly 4 cubic feet / 113 ltr and approx, it came out as 27" tall, 17" wide , 15" deep ( 3.98 c/ft ) I may need to increase that as you recommended 125 litres is better. ( 4.41 C/ft ) Re calc : 27" h x 17" w x 17" d = 4.51 c/ft http://www.thecalculatorsite.com/misc/cubic-feet-calculator.php Edited January 18, 2018 by fleabag Quote Link to comment Share on other sites More sharing options...
stevie Posted January 19, 2018 Share Posted January 19, 2018 (edited) I'm not a fan of rear porting for bass guitar cabs. If you'd like to use a cab of those dimensions, you could use two 5" or 6" ports, which will fit comfortably on a 27 x 17" baffle. There is also the option of a shelf port, but that's not as easy to calculate reliably using modelling software. Edited January 19, 2018 by stevie Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 19, 2018 Author Share Posted January 19, 2018 I'm happy enough to use front ports Stevie - was just curious. I'd prefer to use 4 ports though , as in the plan, so what size area of front would i need to fit 4 ports ? I can adjust the sizes around to still keep the volume at 4.51 cu/ft Quote Link to comment Share on other sites More sharing options...
stevie Posted January 19, 2018 Share Posted January 19, 2018 Just follow the Fane plan. It's all in there, including a useful cutting list. Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 19, 2018 Author Share Posted January 19, 2018 Righteo Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted January 19, 2018 Share Posted January 19, 2018 For the cab experts; When a cab is tuned to a frequency, 50Hz in this instance, is the effect to accentuate or attenuate the sound for that frequency please? Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted January 23, 2018 Share Posted January 23, 2018 On 19/01/2018 at 12:56, SpondonBassed said: For the cab experts; When a cab is tuned to a frequency, 50Hz in this instance, is the effect to accentuate or attenuate the sound for that frequency please? Tuning the cab to that frequency means the cabinet starts to resonate and produce air movement (sound) through the port. This creates pressure on the back of the cone and damps down it's movement so effectively the port takes over making the sound from the speaker. How the cone moves is controlled by the design of the speaker, the volume of the cab and the tuning. The trick is to balance up the speaker, cab size and tuning so the sound stays the same all the way down and all WinISD and the other programs do is to do the balancing act calculations for you. So, as the speaker starts to lose output the port takes over and adds in a bit more sound, ideally just enough to keep the sound level the same but lets you go deeper. 1 Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 23, 2018 Author Share Posted January 23, 2018 Unbelievably, i have 4 to sort out in just one cab ! Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted January 23, 2018 Share Posted January 23, 2018 4 minutes ago, fleabag said: Unbelievably, i have 4 to sort out in just one cab ! I think that's fairly easy to deal with. The specified port area should be a constant whether it is one port or many, circular or otherwise, no? Quote Link to comment Share on other sites More sharing options...
SpondonBassed Posted January 23, 2018 Share Posted January 23, 2018 14 minutes ago, Phil Starr said: Tuning the cab to that frequency means the cabinet starts to resonate and produce air movement (sound) through the port. This creates pressure on the back of the cone and damps down it's movement so effectively the port takes over making the sound from the speaker. How the cone moves is controlled by the design of the speaker, the volume of the cab and the tuning. The trick is to balance up the speaker, cab size and tuning so the sound stays the same all the way down and all WinISD and the other programs do is to do the balancing act calculations for you. So, as the speaker starts to lose output the port takes over and adds in a bit more sound, ideally just enough to keep the sound level the same but lets you go deeper. Thanks Phil. I was curious because of the dreaded 50Hz mains hum that sometimes gets past all of the screening and countermeasures. For a moment I thought that might have been a design consideration when 50Hz was stated to be a good frequency for reflex bass cabs to be tuned to. I'm really only scratching the surface in this subject although as a young man, lots of folk had speaker cabinets off me. I'd buy the drivers and crossovers at Oxford Street on my frequent trips from Dublin to London and put them in cabinets that I'd make to order. I'd do two and three-way speaker pairs. The Punt/Sterling (pre-Euro) exchange rate and price differences between the two countries meant I could do this with no expense to myself and at the same time I got to play with basic speaker enclosure projects. If I was right in the head I could have made good money from my hobby. It wouldn't have been so much fun however. Quote Link to comment Share on other sites More sharing options...
fleabag Posted January 23, 2018 Author Share Posted January 23, 2018 1 hour ago, SpondonBassed said: I think that's fairly easy to deal with. The specified port area should be a constant whether it is one port or many, circular or otherwise, no? Yeah no probs. Just amazed that there's 4 in one cab Quote Link to comment Share on other sites More sharing options...
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