Thoughts on building a 4x15 cab

[Redbrangus]

Something to reflect upon. Voice of the Theatre A7 is a very nice cab.

http://alteclansingunofficial.nlenet.net/publications/techletters/AN-11_EnclosurePlans.pdf

Sorry, but with all due respect, the A-7 is emphatically NOT a very nice cab, IMHO. The performance vs. size ratio is just horrendous. And they don't do LF very well, rolling off substantially below about 60Hz, due in part to the horn being too small. I pushed an A-7-based PA around for years when I was coming up -- I know whereof I speak.

Just for the record, the A-7 "Voice of the Theater" cabs, as big as they are, are the 'compact' version of Altec's theater speakers -- designed to be used in smaller theaters that didn't have the room behind the screen for the huge 215 and 415 horn-loaded systems that were the actual 'Voice of the Theater" systems. The earliest days of rock and roll concert sound adapted these old large-format bass cabs because that was pretty much all there was, but there's no more need of reviving this obsolete technology than there is of designing a car with a carburetor and drum brakes. Time marches on.

I always felt like the problem with the Marshall bass cabs was they were just too small for four 15" bass drivers. If you're determined to build a 415 cab, I hope you allow enough internal volume for this speaker configuration.

 

[beans-on-toast]

Sorry, but with all due respect, the A-7 is emphatically NOT a very nice cab, IMHO. The performance vs. size ratio is just horrendous. And they don't do LF very well, rolling off substantially below about 60Hz, due in part to the horn being too small. I pushed an A-7-based PA around for years when I was coming up -- I know whereof I speak.

Just for the record, the A-7 "Voice of the Theater" cabs, as big as they are, are the 'compact' version of Altec's theater speakers -- designed to be used in smaller theaters that didn't have the room behind the screen for the huge 215 and 415 horn-loaded systems that were the actual 'Voice of the Theater" systems. The earliest days of rock and roll concert sound adapted these old large-format bass cabs because that was pretty much all there was, but there's no more need of reviving this obsolete technology than there is of designing a car with a carburetor and drum brakes. Time marches on.

I always felt like the problem with the Marshall bass cabs was they were just too small for four 15" bass drivers. If you're determined to build a 415 cab, I hope you allow enough internal volume for this speaker

My point was, if you are going to do a 415, think about it and try to do it right. The Marshall design is not the best option, I think that portability was a big concern and limited the design. Mr. Marshall liked the 412 design because it could be built from a sheet of plywood. I ran bass through two 412 cabs. They sounded good but transport was difficult.

A7 is good for home.

 

[agedhorse]

Sorry, but with all due respect, the A-7 is emphatically NOT a very nice cab, IMHO. The performance vs. size ratio is just horrendous. And they don't do LF very well, rolling off substantially below about 60Hz, due in part to the horn being too small. I pushed an A-7-based PA around for years when I was coming up -- I know whereof I speak.

Just for the record, the A-7 "Voice of the Theater" cabs, as big as they are, are the 'compact' version of Altec's theater speakers -- designed to be used in smaller theaters that didn't have the room behind the screen for the huge 215 and 415 horn-loaded systems that were the actual 'Voice of the Theater" systems. The earliest days of rock and roll concert sound adapted these old large-format bass cabs because that was pretty much all there was, but there's no more need of reviving this obsolete technology than there is of designing a car with a carburetor and drum brakes. Time marches on.

I always felt like the problem with the Marshall bass cabs was they were just too small for four 15" bass drivers. If you're determined to build a 415 cab, I hope you allow enough internal volume for this speaker configuration.

Agreed, they were pretty efficient above ~60Hz but fell like a rock below that. They were also large, heavy and unwieldy. I also serviced plenty of theaters with A2’s and A4’s, those were good down to about 45Hz or so with the baffle wings.

 

[five7]

I would look for a couple of used 2x15 or 2x18 PA cabs instead.

 

[Plain Old Barry]

Did you consider an Acoustic 408 cab? Jaco liked those 4x15 too.

Mine was god-awful. It blew center drivers left and right.

The carcass would have been a decent canoe or coffin though!

 

[Milo Spleen]

I gigged with this 4x15 Sunn from 1973 through 1979. It wasn't fun to haul, but I could do it. Notice that this is the "sealed" version, which is the one that I had, but there is also a ported version. I never pushed this cab and only used a Concert Bass amp with it, but we played in some big rooms and it was certainly capable. I get a better tone with a 2x15, so I recommend 2 2x15s all with the same driver because I'm 71 years old now. lol.

Edit: I just saw that at the bottom, this may have a tiny slot port.

 

[kesslari]

The question to ask yourself is - "Do I want to play loud music with good bass tone, or do I want bragging rights?"
The 4x15 you describe is for bragging rights - I have a 4x15, man.
For good sound, loud - look into some of the alternatives that folks have suggested here.

 

[dawind99]

I'm thinking about building a 4x15 cab and looking for a bit of extra input.

The plan is to copy the dimensions/design of a Marshall 1979 cab which is roughly 35x35x16.
From my understanding Marshall made a couple of other cabs like this; the difference being the speakers. The original 1979 had G15V Greenback. The 1979L6 "Lemmy Cab" I'm not sure which speakers were used. I also think they made a JCM800 bass 415 cab with 15" sidewinders. I know for sure there was a 2x15 JCM800 bass cab with sidewinders in it.

G15V greenbacks are out of the questions. If they ever come up for sale they're too expensive. If I can find a quad of 15" sidewinders at a decent price I'd go with those. The most likely set of speakers would be Weber Werewolf 15's. Obviously I'd go with the bass version. This is their description:

TONECVLT 15″, 60oz Ceramic magnet, Can be used for guitar or bass depending on the voice coil chosen – 80w guitar style or 150 watt for bass, 2″ voice coil, cloth-edged ribbed bass cone, large H dustcap, heavy dope. Crisp, clear tone with tight low end. (Big natural low end.) Even frequency response.

Here's a video from Fuzzlord of an emperor cab with a Grey Wolf and Werewolf speaker. It's mainly with guitar, but there are portions of the isolated werewolf speaker. Hopefully it can give a decent idea of what the werewolf would sound like. There's also a quick demo with a bass at the end, but I think it's both speakers combined.



My intent is to use it with vintage style "all purpose" tube amps. A few examples are Fender Bassman, Marshall Super Bass, Sunn Model T, Orange/Matamp GT120. (side note I'll be building clones of these amps myself). So wattage handling won't be a problem. The cab would be able to handle up to 600 watts and most of the amps will be 100-150 watts. The cab will more than likely stay in my "studio" so transportation won't be an issue. If I do bring it anywhere I have a large dolly & and a truck to haul it around in.

Here's where I'm looking for a couple of opinions.

1. I'd also use this cab with a SVT style amp. SVT's are generally associated with their respective 8x10 cab. Anyone use a 2x15 or 4x15 of similar style I'm planning with an SVT. If so did it sound decent? Or does an SVT really need 10" speakers to sound its best?

2. I've successfully built several guitar cabs. I've done/been doing my research on this 4x15 cab. I think I have it figured out for the most part, but I've also not built something of this caliber. I know bass cabs have more to their design than guitar cabs. At the same time this one will not be ported and is copying a pre-designed Marshall bass cab. Is this a worthwhile project to tackle, or am I possibly setting myself up for massive failure?

3. Any other random thoughts on this project that you think may be helpful.

Do it. Fun project and folks don't seem to be reading your post: 1) you are not going to be moving it around much so weight is not a barrier. 2) you want a 4-15 not a 2-15 and not (2) 215s 3) You did not ask for advice on which "production" cabinet to purchase. Find the Sidewinders! The sidewinders were brilliant drivers for bass, both the 12s and 15s. The 12s were designed for guitar and I built a 412 cab for myself that I used briefly. Briefly because they would peal paint at a 100ft with my JMP50. The tone was also far from optimal for guitar. BUT, for bass or FOH emphatic yes. Celestion only produced them for a few years as the failure rate during manufacture was astronomical due to the ribbon wound voice coils. The only people that could wind them with consistent success were a handful of women that had been at Celestion/Rola from the beginning of time and were artisans. They attempted to train people to do it with little to no success and thus the Sidewinders fell by the wayside. The "ribbon" wound voice coils was key in their extremely fast response, output and higher power handling due to heat dissipation. They had a sensitivity that was rare in that time at @ 101-102db 1 watt/1 meter hanging off a 'coat hanger" in free space. They were extraordinarily loud and clear. AND, with a cast aluminum frame they were very light at a time when 15" drivers were far from. With JBLs (which blew at 100 watts), EVs (which did not and were superb) both sounded great, both heavy. And there were Gauss....massive power handling, super heavy, toneless, slow, "boat anchors". The Sidewinders pushed the envelope in driver design. Build your cab and enjoy. If you need a design I'll help with the porting if you like. Do not make it square! That will be the kiss of death. I built stacks: 115 cabs with 210+tweeter cab on top for Gato Barbiere's band, Robert Palmer's band, The Alman Brothers keyboardist: Chuck Leavell and bassist "Rook" Goldflies. The top cab was not ported and held a pair of 80 watt 10s also Celestions. I do not remember the model of the 10s. I also built my bass player a pair. Yes he still has them and yes, unbelievably they still work and sound very good. They were also very light cabinets. I built them out of 3/4" luan mahogany. Yes, light. The single 15 cab was rather large and had a single port simply cut in the baffle. Best of luck with this fun project!

 

[RandomKaren]

4x15, why stop there? 8x18 is the way to go

 

[agedhorse]

Celestion only produced them for a few years as the failure rate during manufacture was astronomical due to the ribbon wound voice coils. The only people that could wind them with consistent success were a handful of women that had been at Celestion/Rola from the beginning of time and were artisans. They attempted to train people to do it with little to no success and thus the Sidewinders fell by the wayside. The "ribbon" wound voice coils was key in their extremely fast response, output and higher power handling due to heat dissipation. They had a sensitivity that was rare in that time at @ 101-102db 1 watt/1 meter hanging off a 'coat hanger" in free space

Edge wound ribbon wire voice coils have been made successfully for over 6 decades, I can't believe Celestion had so much trouble mastering this basic construction method.

That free-space (outside an enclosure) sensitivity is only valid above maybe 200-300Hz, the low frequency sensitivity is very much cabinet dependent. The sensitivity is higher than most multi-purpose speakers of the day, but on par with the "equivalent" JBL and EV models in an enclosure, broad band.

 

[TheReceder]

In my younger days I had an acoustic 408 4x15 with a model 320 head. I was very happy when my back was hurting from hauling it, and it moved enough air to give a massage.

 

[rogypop]

Building outrageous cabs is fun, do it. However there is a right and wrong way of building speaker cabinets, do it the right way because you are investing yout time and money in it after all.

2+2 baffle configuration is bad, especially with 15 inchers. Your mids and highs will be beaming badly and off axis you will get nothing but muddy thud.

The best way of doing it woud be mounting 3 drivers in vertical or slightly staggered row, with the fourth driver mounted on the BACK of the cab that would add another dimension to the tone by bouncing highs of the wall and cure null zones in bad rooms.

Eminence Delta 15 and Beta 15 are rare drivers which will adequately cover full range of the bass guitar in a sealed cab, allow at least 2 cu ft per speaker.
Anything thicker than 1/2 inch plywood will only add weight, for panel stiffness employ a simple cross bracing structure.

If built this way you will get a formidable but massive sounding bass guitar cabinet, not just a stage decoy.

Best of luck, Igor

 

[walterw]

The question to ask yourself is - "Do I want to play loud music with good bass tone, or do I want bragging rights?"
The 4x15 you describe is for bragging rights - I have a 4x15, man.

exactly!

in fact i'll wager that's the main reason marshall built the thing in the first place, because it would look intimidating and "just because they could"

 

[ajkula66]

exactly!

in fact i'll wager that's the main reason marshall built the thing in the first place, because it would look intimidating and "just because they could"

It was meant to be used in pairs with a Marshall Major head, which in itself didn't look intimidating but had plenty of power - 200W - for 1967. Now, the full stack did look quite intimidating...

 

[dawind99]

Edge wound ribbon wire voice coils have been made successfully for over 6 decades, I can't believe Celestion had so much trouble mastering this basic construction method.

That free-space (outside an enclosure) sensitivity is only valid above maybe 200-300Hz, the low frequency sensitivity is very much cabinet dependent. The sensitivity is higher than most multi-purpose speakers of the day, but on par with the "equivalent" JBL and EV models in an enclosure, broad band.

80+ years I believe but, they did with that particular driver. I'd say training was the issue. And, all the JBLs blew up. All of them. None of the EVs did nor the Celestions. If the JBL was rated at 150 watts at 151 you could kiss it goodbye,

 

[agedhorse]

80+ years I believe but, they did with that particular driver. I'd say training was the issue. And, all the JBLs blew up. All of them. None of the EVs did nor the Celestions. If the JBL was rated at 150 watts at 151 you could kiss it goodbye,

JBL's properly run (not abused) were every bit as reliable as the EV's and Celestions. A good example of a similar scenario was the original Celestion V-30, they too were a reliable driver reasonably powered, but had an astronomical failure rate when abused. The paper bobbin couldn't take abuse, similar to the tight gap of the (vintage) JBL drivers. I reconed a ton of V-30's and D/K series JBLs back in the day, almost always, the root cause of the failure was too much power (both thermal and mechanical).

I also ran a (very large) PA that was all JBL drivers, I don't recall ever having one fail, but it was powered reasonably, and protected reasonably. That was over a thousand shows.

 

[dawind99]

JBL's properly run (not abused) were every bit as reliable as the EV's and Celestions. A good example of a similar scenario was the original Celestion V-30, they too were a reliable driver reasonably powered, but had an astronomical failure rate when abused. The paper bobbin couldn't take abuse, similar to the tight gap of the (vintage) JBL drivers. I reconed a ton of V-30's and D/K series JBLs back in the day, almost always, the root cause of the failure was too much power (both thermal and mechanical).

I also ran a (very large) PA that was all JBL drivers, I don't recall ever having one fail, but it was powered reasonably, and protected reasonably. That was over a thousand shows.

We had different experiences. We'll leave it at that.

 

[Aidenn7]

after going down this rabbit hole. I looked at Lemmys stack. there was a reason for having a 412 and a 415. instead of just a 415. and he had the bass all the way down. So I going say you are prolly pissing in the wind for fun. I come to conclusion a deep Marshal 4x12 with evm 12's with tuned back porting accomplish more and handle bass better. The reason for the Acoustic 408 being better. one easier to move. and it used a solidstate amp. needed no stuffing to work- just the cab by itself.