Jono Bolton Posted July 13, 2016 Share Posted July 13, 2016 I've got a 2x15 cab and have given some thought to replacing the speakers; at the moment it has two 3 ohm PA subs, wired to 6 ohms. It sounds good, but it weighs a ton with the cast frames. Ideally I'd like to have it wired to 4 ohms, and to lose a bit of weight from it; in terms of sound I'd like it to be as clear as possible as I use a pretty low tuning and 15s can end up getting a bit muddy and boomy. Any suggestions? Quote Link to comment Share on other sites More sharing options...
3below Posted July 13, 2016 Share Posted July 13, 2016 If you provide the internal dimensions of the cabinet, the current port diameters and lengths, you will find that others will be along with suggestions based on the modelling software. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted July 13, 2016 Share Posted July 13, 2016 Yep, the dimensions are pretty much the starting point. I'd not recommend anything without knowing that at least they match the cab well enough to handle the power you are likely to use. Is there a budget limit? It wouldn't be hard to spend £200 a speaker. Quote Link to comment Share on other sites More sharing options...
Jono Bolton Posted July 13, 2016 Author Share Posted July 13, 2016 Sorry chaps, I'm not very au fait with this sort of stuff. The front grill is a pain in the arse to get off but luckily I found the following over on Talkbass: "Internally, each chamber of the cab is 12" deep, 24" wide, and about 18.5" tall. Each port is 7"x7"x9" and the speaker baffle is 3/4" thick." The ports are triangular cutouts. Quote Link to comment Share on other sites More sharing options...
SubsonicSimpleton Posted July 14, 2016 Share Posted July 14, 2016 As a starting point, you might want to weigh the cab as it is now and demount and weigh one of the existing drivers - just by way of illustration I did this with my ashdown 1x15 extension a while back to see whether I could make loading easier, and the driver was less than 20% of the total weight of the cab, so from a weight saving perspective changing from the existing ceramic magnet driver to a lightweight neo magnet driver would have been very expensive and shaved about 5-7% of the total cab weight. To really make substantial weight savings on the cab in question would have required re-engineering it with more expensive materials (original construction is chipboard/mdf baffle) which seemed a bad idea considering the quality of the driver. The PA subs in your cab might be substantially heavier than the ashdown drivers, so the maths might make sense in your case, and you can at least try adjusting the weight of the cab by removing one or both drivers and adding ballast to simulate reasonably accurately the weight of the new drivers to see if that weight saving is really going to make the difference you are hoping for. Quote Link to comment Share on other sites More sharing options...
Jono Bolton Posted July 14, 2016 Author Share Posted July 14, 2016 The weight isn't my main concern, it's mostly the sound and also the impedance; a lot of our gigs involve cab sharing and I'd rather have a standard impedance like 4 ohms than 6, especially if anyone brings something with valves. I'd also get more power from my head by doing so. It would be nice if the cab was lighter but it's never going to be a one-man lift either way so it'd be nice to have but isn't a deciding factor. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted July 14, 2016 Share Posted July 14, 2016 just looked at the cab in your gear, is it the Peavey that matches the Mk IV head, I used to have one of those, They came with two Black Widow 15's with the metal domes if it is the same cab which gave quite a nice bright tone. If it is then the dimensions are a bit off. Quote Link to comment Share on other sites More sharing options...
3below Posted July 14, 2016 Share Posted July 14, 2016 (edited) 6 Ohms is quite OK. Solid state amps will just deal with that, problems start at low impedance. Some solid state amps will deliver down to 2 ohms, others get a little unhappy with less than 4 ohms. As I understand it, if you have an impedance mismatch with valve amps a speaker impedance less than amp output impedance is preferable (e.g.speakers 6 ohm, amp output 8 ohms). The 'rated' / 'quoted' impedances are not exact since they change with frequency (and quite significantly around resonance). With only 2 ohms difference between 8 and 4 with your 6 ohm cab I would not worry about it, but then again it is not my kit. If you want a 4 ohm 2 x 15 bass cab that is virtually indestructible my advice would be sell the Peavey and add your proposed replacement driver expenditure to that. Use it to buy a BF Dubster or Vintage. It will be (IMO) far more cost effective and someone else has done all the design work for you. Biased viewpoint, I have a BF Dubster and s/h it cost less than the drivers it contains. Edited July 14, 2016 by 3below Quote Link to comment Share on other sites More sharing options...
Jono Bolton Posted July 14, 2016 Author Share Posted July 14, 2016 [quote name='Phil Starr' timestamp='1468525052' post='3091602'] just looked at the cab in your gear, is it the Peavey that matches the Mk IV head, I used to have one of those, They came with two Black Widow 15's with the metal domes if it is the same cab which gave quite a nice bright tone. If it is then the dimensions are a bit off. [/quote] Yep, it is the cab that goes with the head. There were two versions; mine is the shallow version, but there was a larger, deeper version which was more common. Mine would have originally had BWs but the ones from this cab are long gone. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted July 15, 2016 Share Posted July 15, 2016 (edited) OK, If you wanted original I suspect the one I used would be available. It belongs to a friend and sits there unused. There's lots of old Peavey cabs out there with BW's in but beware there are several models I think Eminence Basslites would work well in this cab and give you a worthwhile reduction in weight with a similar sort of sound to the original speakers. The Eminence 3015HO might also work but I'd want to check the dimensions and run a full set of calculations before recommending them firmly. As I remember the cab was actually rather small for the original BW's and tuned too high but sounded nice nonetheless. Unfortunately I know I won't see my mate for the next few weeks, we play in a duo together. That means I can't measure the cab myself. These are both quite pricey recommendations, there are cheaper options if you want. Edited July 15, 2016 by Phil Starr Quote Link to comment Share on other sites More sharing options...
Jono Bolton Posted July 17, 2016 Author Share Posted July 17, 2016 Thanks for all the replies. I took my cab to practice today (for the first time since I got my Peavey head I now realise) and it's safe to say the drivers aren't going anywhere; even though I'm probably getting less than 200 watts out of it it's ridiculously loud and the PA drivers handle the lows, mods and highs better than any driver I've used before. 15s can be quite bassy and muddy but the cab is one of the clearest I've heard. If only it weren't so bloody cumbersome! Quote Link to comment Share on other sites More sharing options...
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