DIY Cab Advice...

[Docaroo]

Hey Chaps,

I'm about to begin building a pair of 2x12 cabs for a stereo set up.

I go from my Boss GT8 in stereo to a Peavey Classic 50/50 Tube Poweramp - which will feed 2 2x12 cabs!

I just need some advice on speaker selection and ohm's and wattage and all that stuff!

What is the ideal ohm/wattage speaker for the Peavey Poweramp- it has the following switching options for output:

Stereo output selection 4,8 or 16 ohms, 50w RMS each side, 28.3v RMS.

Would 16 or 8 ohm speakers be best? and why? Also which models would you suggest? I play Heavy metal/power metal stuff so have heard great things about Eminence - any models I should look out for?

One other thing, would the 2x12's be best horizontal (wide and low) or vertical with the top speaker angle up a bit (like an angled cab sawn in 2) - if you see what I mean? I think if they were verticle and angled it would be better for soudn projection? any ideas?

I'm competent at DIY/wiring but have never got into speaker ohms and all that stuff (yet) so I would appreciate explanations aswell as recommendations!

Thanks in advance everyone!

[Zaphod B]

Regarding the angling of the speakers:

I think its a good idea and there are several ways you could do it.

1. Angle the entire baffle board - say, if the cab will be used horizontally, angle the whole board so that it's tipped back a bit.

2. Angle half the baffle - one speaker

3. Angle both baffles, so that they form a wide "V."

Good luck, and let us know how it turns out!

[Track Rat]

The impedence of the individual speakers you'd buy depends on how you want to connect them together so their TOTAL impedence matchs the load the amp wants to see. Say the amp wants an 8 ohm load, two two 16 ohm speakers wired in parallel would represent a 8 ohm load to the amp, or 32 ohms if wired in series.

[ocnor]

By the time you purchase all of the materials and speakers to build your own it isn't cost effective. You would be ahead of the game by finding an inexpensive 4X12 cab and rewiring it for stereo.

[Docaroo]

track rat... ok that makes sense - but then what is the best way to wire for the peavey do you think?

50w each side and choice of 4/8/16 ohm? Is it best to use highest ohm available to the amp? taking a guess it seems 2 8ohm speakers wired in series for each cab (amp set at 16ohm) seems do-able?? what do you think?

@Zaphod - my thinking was imagine an angle 4x12 cab, bottom half flat and top baffle half angled - then "saw" that straight vertically down the middle...

So you have 2 2x12 cabs standing "high" not "low" with the angle? that's propably what i'd go for... would be a really cool set up i think!

thanks guys!

I th

[Docaroo]

Originally Posted by ocnor

By the time you purchase all of the materials and speakers to build your own it isn't cost effective. You would be ahead of the game by finding an inexpensive 4X12 cab and rewiring it for stereo.

I doubt it... I have a 4x12 cab that I want to sell... plus i want 2 2x12s so i can serperate them for good stereo seperation - i don't see the point in a stereo cab if all the speakers are right beside each other!

4x speakers, off ebay are maybe around £180 max??? wood and stuff is not going to be more than say £50-£100 ?? So I think £300 budget for these cabs is fine? Plus I have my cabs they way I want... do you know where i can get 2 angled cabs like this anywhere lol?

Plus theres the satisfaction of the DIY work...

[iqi616]

I would strongly advise googling cab designs. The cab has a huge effect on the sound. I ran a pair of homebuilt 2x12s for a number of years and wondered why my bass sound sucked until I plugged my amp into a Trace Elliot cab and it was like night and day.

[Zaphod B]

Originally Posted by Docaroo

@Zaphod - my thinking was imagine an angle 4x12 cab, bottom half flat and top baffle half angled - then "saw" that straight vertically down the middle...

Sounds good.

Originally Posted by Docaroo

So you have 2 2x12 cabs standing "high" not "low" with the angle? that's propably what i'd go for... would be a really cool set up i think!

Yep, that would work!

[ocnor]

Originally Posted by Docaroo

wood and stuff is not going to be more than say £50-£100 ?

Just the tolex and grill cloth alone cost $25-$50 a yard. Birch plywood is about $40 a sheet. Then you need handles, corners, jacks, wire, screws , etc.. Decent speakers are upwards of $100 each. Unless prices are very different where you live a budget of £300 isn't going to cut it. I wish you luck on your project.

Originally Posted by iqi616

I would strongly advise googling cab designs. The cab has a huge effect on the sound.

That is good advice.

[Docaroo]

Originally Posted by ocnor

Just the tolex and grill cloth alone cost $25-$50 a yard. Birch plywood is about $40 a sheet. Then you need handles, corners, jacks, wire, screws , etc.. Decent speakers are upwards of $100 each. Unless prices are very different where you live a budget of £300 isn't going to cut it. I wish you luck on your project.

I'm not sure where you get your prices from but they are just wrong! Meant with all due respect:

Eminence speakers are around £20-£40 each...

I don't have to use "tolex" and grill cloth! That's why it's DIY, I'm not sure what I'll cover the wood with yet but it'll be cheaper than $50 a yard I assure you! Instead of Grill Cloth I think I will use black wire mesh.... very cool looking (used on H&K Vortex Cab)...
Handles, corners, jacks, wire, screws, castors - Not very much from ebay!

4 x £40 for speakers - £160
I'm sure the other £140 would cover wood and hardware easily?? surely!

anyway back on track: Speaker wattages!!

I am planning on using an 2x 8ohm Eminence speakers for each cab (wired in parallel so providing an 8ohm load for the power amp) - is this ok?

Also what wattage should the speaker be? I'm seeing people say don't make it too high for the amp? So the amp is 50w RMS - should the speaker be somewhere around 50w-60w or can I go higher?

Also, what if I use the amp in Mono, 100w RMS? Is this possible with 50w speakers?

Thanks!

[Docaroo]

this place seems to be good for wood supplies - nothing too pricey there!

http://www.elitetimber.co.uk/plywood.htm

[travelin travis]

stay away from that chinese plywood. it's shit!

what speakers do you have experience with? any that you particularly liked?

[c7sus]

WTF are you getting 3/4" birch for $40???

Cabinet-grade birch up here is $55/sheet. The good stuff is about $75.

A-Grade Oak is about $95.

[ggunn]

You should make your speaker array have twice the handling power of the rated output of the amplifier, especially with a tube amp. The impedance (ohms) really doesn't matter as long as it matches what your amp wants to see - a bit higher is OK, but not lower.

Do you know how to figure impedances and wattage ratings with multiple speakers?

[travelin travis]

Originally Posted by c7sus

WTF are you getting 3/4" birch for $40???

Cabinet-grade birch up here is $55/sheet. The good stuff is about $75.

A-Grade Oak is about $95.

http://homedepot.bighammersoftware.c...spx?cid=834246

[c7sus]

That explains it.

It's apples and oranges. The stuff Home Depot calls "cabinet grade" ain't the same stuff that the independents around here are selling, it's much lower quality.

[Zaphod B]

Originally Posted by c7sus

That explains it.

It's apples and oranges. The stuff Home Depot calls "cabinet grade" ain't the same stuff that the independents around here are selling, it's much lower quality.

Home Depot cabinet grade is for kitchen cabinets - but it works very well for its intended purpose!

[Docaroo]

Originally Posted by ggunn

You should make your speaker array have twice the handling power of the rated output of the amplifier, especially with a tube amp. The impedance (ohms) really doesn't matter as long as it matches what your amp wants to see - a bit higher is OK, but not lower.

Do you know how to figure impedances and wattage ratings with multiple speakers?

Ok so if I stick with the 2x 8 ohm speakers and have their wattage at 100w or more I'm good??

[Docaroo]

I don't understand why you need "the very best quality wood" for a guitar cabinet.. it really is un-necessary because the wood contributes very little to the sound, it's just a method of making the cabinet air-tight!!

Save the expensive wood for your guitars!!!

[travelin travis]

Originally Posted by Docaroo

I don't understand why you need "the very best quality wood" for a guitar cabinet.. it really is un-necessary because the wood contributes very little to the sound, it's just a method of making the cabinet air-tight!!

Save the expensive wood for your guitars!!!

No one likes a cabinet that rattles.

[Zaphod B]

Originally Posted by Docaroo

I don't understand why you need "the very best quality wood" for a guitar cabinet.. it really is un-necessary because the wood contributes very little to the sound, it's just a method of making the cabinet air-tight!!

Save the expensive wood for your guitars!!!

What you need for a guitar cab is a void-free, non-resonant wood and 13-ply baltic birch plywood is considered the best.

You can also make great cabs with MDF (medium-density fiberboard) although the woodworking purists turn up their noses at it.

The goal, though, is to make a cab that is strong, tight, non-resonant, and tough enough to withstand whatever road torture you plan on subjecting it to.

[travelin travis]

I don't think 'non-resonant' holds true with guitar cabs.

[Zaphod B]

Originally Posted by TravisinFlorida

I don't think 'non-resonant' holds true with guitar cabs.

"Resonant" and "rattling" are the same thing, just at different frequencies.

Particularly with a closed-back cab, any tendency of the cab to resonate translates directly into lost efficiency. I don't guess it matters so much with open-back designs.

[travelin travis]

'rattling' is when something is lose and being vibrated by resonation, such as a piece of hardware or piece of wood (void).

[Docaroo]

wow baltic birch plywood is cheaper than i thought it would be... looks like that could be the way??

Also what's the best material for the baffle? MDF?