Bass Amp to Guitar Speaker Cab

[horax]

My daughter's band at her high school was going to throw away a well used Hartke 1415 bass amp.
Teacher said it was beyond fixing.
I looked at it and saw there were no speaker wires connecting the amp portion to the actual speaker.
He said I could have it. Boo ya.

I don't play bass, but I always wanted to make my own cab so I could have an excuse to buy a few amp heads for swapping, etc.

I tore into this thing....it had old school carpet instead of tolex, so I got it all off. The box is plywood...and it's THICK! It's glued together, too.

Before I spend money on this, will the thickness of the cab and the fact that it's glued affect the tone of the speaker?
I'm sure it will as the cab won't flex like a regular guitar cab....this is like nearly 1" thick.

Thoughts?

 

[2L man]

Thicker and heavier cabin color the sound less so you can use it for guitar. Some bass cabins have "ports or ducts", does yours?

 

[horax]

Thicker and heavier cabin color the sound less so you can use it for guitar. Some bass cabins have "ports or ducts", does yours?

It does. It has the circular port on the back. I was considering making it larger, possibly, but not sure if I should.

 

[2L man]

Then it is simpler "open back" cabinet and depending cab size there comes some "acoustic cancelation" around 300...800Hz when sound wave what leak out of port to the rear comes opposite 180 decree phase (90...270 decree range) to front side. And some acoustic amplification usually to 200Hz and lower frequency range when sound wave comes delayed better 360 decrees (starting from 270 decrees) later. But highs should sound more "open and colored" bit more interesting when cone can vibrate easier when it can "breathe"

 

[radiocaster]

I have the head version of that amp, not bad.

The thickness of the wood, glue, covering have no effect on the sound. The dimensions of the cab do, and the fact that it's pretty deep will make it sound bassy even if you remove the back. Whether you like the sound or not is another matter.

 

[brenn]

It does. It has the circular port on the back. I was considering making it larger, possibly, but not sure if I should.

I'm no amp expert, but I seem to recall that the size and position of the port is a math problem to be worked out, that affects the sound, not a style choice.

 

[SerpentRuss]

I'm no amp expert, but I seem to recall that the size and position of the port is a math problem to be worked out, that affects the sound, not a style choice.

You're absolutely right, there is a lot of math that goes into a good ported design. That said, most guitar speakers are designed to work in an infinite baffle, so a completely open back cabinet. Many bass drivers are not, hence the well-engineered port.

Making the port bigger substantially bigger would be fine if you were mounting a guitar speaker and planning to play guitar through it.

 

[echuta13]

I don't think the porting will have much of an effect since guitar speakers (assuming you replace the speaker) really don't have much in the way of excursion. You could always open up the port to operate more like a open back cab, and/or create a plate for the port to close it up which should tighten/focus the sound. Joinery really doesn't affect the tone IMO provided it isn't a hack job.

I haven't monkeyed much with depth on cabs, but many on the interwebs say that deep cabs = mo'bass. This could mean muddy, boomy, full, or just "accentuated". Take that with some salt.. The fact that it is a beefier cab may minimize this effect.

 

[NoTeleBob]

My WAG is that a thicker, stronger plywood cab is just going to resonate more, not less. Likely a good thing, speaker, humidity, astrology, and wind direction notwithstanding. If it was MDF, then it might be sucking up sound.

I've discussed the issue of cab depth when the cab is fully open with sound engineers before. No strong conclusions that 10" is a lot different than 15" when the back is open.

If you want it shallower though, why not cut it down? Sounds like the type of construction where you could draw a line and run a circular saw (using guide board) around the cab and take 4" off. Then redo the Tolex as I imagine you are planning.

Speaker selection probably makes a bigger difference here than anything. The Eminence Redcoat line tends to be bright (British) and efficient for a very reasonable price. Might compensate for the cab sucking up some highs. Or their Patriot line to cut back the chime a bit.

 

[schmee]

I've found that cab depth and cab wood thickness can make a difference. Bass cabs are thick because of the vibration.
Depth is a bigger factor to my ears. Anything over about 11", maybe 12" max, even open back, starts to get woofy.

 

[horax]

I do want to get a different speaker. The one in there is broken in, but I'd prefer something like a Weber or something....15" speakers are expensive!

Kind of wish this cab was screwed together so I could take it apart and redeisgn if necessary...but iwth it being glued I'm stuck (no pun intended) to using a 15" speaker.

I am giong to re-tolex, yes. Im' going to take the top off of the cab as it is only there to hold the amp portion itself.
I might consider taking some off of the back as well to make it more shallow (with an open back design). Would make it much easier to work with, as well.

 

[cometazzi]

I do want to get a different speaker. The one in there is broken in, but I'd prefer something like a Weber or something....15" speakers are expensive!

Kind of wish this cab was screwed together so I could take it apart and redeisgn if necessary...but iwth it being glued I'm stuck (no pun intended) to using a 15" speaker.

I am giong to re-tolex, yes. Im' going to take the top off of the cab as it is only there to hold the amp portion itself.
I might consider taking some off of the back as well to make it more shallow (with an open back design). Would make it much easier to work with, as well.

You could bolt a second baffle (with a 12" hole) to the backside of the one in there as an adapter. You'll probably have to fasten it in several places so it doesn't rattle. Sounds like the cab already weighs as much as a truck so it won't add too much.