Both rear and front mount in a cab?

[AntonHu]

Hi guys,

I’m building a 2x12 vertical cab. Straight, closed and dimensions approx 30x20x14 inch. 3/4 Burch ply with a glued baffle.

Speakers to be fane crescendo 12a replica at the top, with a celestion G12t-75 in the bottom. The celestion is there to add bass and balance to the fane. I’m targeting a clean full sound.

I understand the frequency response for front loading is more focussed on highs, with a more precise sound. Rear is more mids focussed and well rounded.

Is there any reason (tonally and technically) I can’t front mount the top fane and rear mount the bottom celestion?

Thanks in advance!

 

[printer2]

Oh goodie, a cab that goes both ways.

Just what I thought when I first saw the title. On difference in tone due to speaker placement? I highly doubt it.

 

[telemnemonics]

I’d be more concerned with practical matters like grille cloth on the front and speakers on the back.
I associate front mount with cheap cabs so maybe that makes the tone shrill too?
I certainly notice too thick of a baffle makes the sound stiff and less warm.
Are you using 3/4” for the baffle?
Can you go to 1/2”?
A glued in 3/4” baffle could be very regrettable.

 

[AntonHu]

I’d be more concerned with practical matters like grille cloth on the front and speakers on the back.
I associate front mount with cheap cabs so maybe that makes the tone shrill too?
I certainly notice too thick of a baffle makes the sound stiff and less warm.
Are you using 3/4” for the baffle?
Can you go to 1/2”?
A glued in 3/4” baffle could be very regrettable.

it does seem rear mounting is the standard in the better cabs.

I can go any thickness for the baffle. Just assumed 3/4 was the industry standard. I don’t want it too stiff. Btw I’m targeting gilmour/floyd tones.

 

[AntonHu]

Oh goodie, a cab that goes both ways.

Just what I thought when I first saw the title. On difference in tone due to speaker placement? I highly doubt it.

That would be interesting . Could call it the bi-cab’

 

[Ringo]

Buzz Feiten used to make a 2-12 cab that had one front and one rear mounted speaker.
Not sure that you'd really hear a big difference but why not try it.

 

[wrathfuldeity]

You might want to not permanently/glue the baffle until you got some time in and you can still change things out. I don't know why you could not experiment with different baffle thickness. 3/4 inch will be more stout/punch and 1/2 will be looser.

 

[Peegoo]

I fairly certain @AntonHu is referring to whether to mount the speakers on the front of the baffle or on the rear of the baffle--not one speaker pointing forward in the cab and the other pointing backward on the back.

Generally, a rear-loaded speaker is a bit 'beamier' than one that's front-loaded (beamier, meaning highs are more greatly concentrated along the speaker axis). Doc Z doubles up on the 3/4" ply of some of his combo and speaker cabs and rear-loads the speakers, and they project like a cannon.

It depends on your application. Playing small rooms? Front load and open back to spread the sound around better. Playing deep stages where you need to shoot your sound forward? Rear load and closed back.

A rear-load with an open back is a pretty versatile compromise; the open back spreads the sound around near the amp, and the rear load beams most of it like a spotlight.

 

[printer2]

A 12" speaker is going to beam, also the highs are more generated at the voice coil and decouple from the rest of the cone to an extent. You find that by micing off center at the cone. So having 3/4" hole to send the sound through is not going to make any difference. The reason most cabs are rear mounted is it is easier and it protects the speaker a little more. Also you can permanently fix the grill cloth and be able to service the speaker with it back loaded. You could make the grill removable and front mount the speaker but most manufacturers would not bother. I really do not buy into the secret sauce of mounting the speaker in the front or back will change the operation of the speaker in the cabinet. Go look at some frequency response graphs and think about the physics behind it. This is not rocket science.

 

[schmee]

I dont see any reason not to do it.
BTW; Think twice before using 3/4" for the speaker baffle, I find it effects tone, and not in a good way for guitar. But you may like it, hard to say.

 

[Ringo]

Apparently Fuchs Audio is making that Feiten cabinet now - here is some info and pictures
Fuchs Feiten 212 Guitar Speaker Cabinet (130 Watts, 2x12") (zzounds.com)

I thought about building one years ago, but it's closed back and for the types of music that I play open or semi open back cabinets seem to work better.

 

[printer2]

Oh I see, two speakers offset. Surprise, surprise I read a couple of paper recently from the 50's on acoustic loading of two speakers and a newer on line array columns. The signal from the bottom is slightly out of phase as compared to the other and the sound is only in phase at an angle to the two. It might cause a lobe in the SPL to be angled up. I haven't the interest to bother thinking of it deeply but is anyone feels like it here they are. I also did a search,"

Mutual Coupling Between Loudspeakers - Mutual Coupling Between Loudspeakers.pdf

http://send.saleslayer.com/4062b995b2f5cc8854c697986682e36a/WP_LINE_ARRAYS-HOW THEY WORK.pdf

This page helps to in explain on multiple speakers sound combining. There may be more, not my interest.

https://www.hifizine.com/2010/06/the-controlled-pattern-offset-bipole-loudspeaker/

I say if you want to try it, it is not a hard thing to do. Make it that you can mount the speakers either way, in the front or the back. The only down side is the front of the cabinet will be greater than if you had the speakers mounted in the back. That can be trimmed off if you decide to go with both internal speakers.