Open-back cabs- Does size matter?

[cousinpaul]

I've been doing a lot of playing through a friend's 1X12 Princeton Reverb along with my own 5E3. Both sound very good to me. Is there any benefit to going with a larger cab? I'm in the process of putting a grab and go cab together to pair with my Quilter Tone Block. Speaker will be an Eminence Lil' Texas.

 

[telemnemonics]

Not really for an open back cab, the same spkr in a PR and a DR cab will sound pretty much the same, though there are semi open designs where size comes into play.

 

[No457 Snowy]

It might depend on the amp and speaker size to cab size I think, I only say this because I do this with a Blues Junior into a larger open back cab with the exact same type 12" speaker (CRex) as I have in the stock cab and it makes a noticeable difference (for the better) with that particular amp.

 

[jhundt]

many people feel that a larger open-back box sounds better, and that smaller open-back cabs can produce some 'boxy' tones.

 

[homesick345]

many people feel that a larger open-back box sounds better, and that smaller open-back cabs can produce some 'boxy' tones.

I agree - this was always my experience.

 

[Silverface]

Yes! A larger open back cab - especially a solid-wood one - will increase the natural resonance...almost a "reverb" effect....of a good amp.

But it has to be a well built, high quality cab. Pressboard cabs of any size are sonically dead, and a larger one may actually kill some volume by absorbing the vibration of the speaker(s).

The design of the open-back i also important. Traditional Fender open backs don't change as much with size as backs with tuned panels (slats and specifically shaped holes placed at very exact positions behind the speaker(s).

Cabinet design and construction is far more important than many would guess, because the majority of players nowadays have only played through amps/cabs that are reissues and/or made of pressboard. Vintage and boutique gear exposure can gve you a completely different perspective.

 

[uriah1]

I heard a 1/4 open cab that sounded phenomenal..

 

[GuitarJonz]

.....The design of the open-back is also important. Traditional Fender open backs don't change as much with size as backs with tuned panels (slats and specifically shaped holes placed at very exact positions behind the speaker(s).....

Interesting. So assuming you were building a larger solid pine cab for a tweed deluxe with a 15" speaker, how would the sound differ between a traditional tweed deluxe style open back cab, and a cab with a hole in the back, perhaps oval, as seen below? I assume the oval would only be effective if the speaker is centered in the cab, not offset.

 

[telemnemonics]

Interesting. So assuming you were building a larger solid pine cab for a tweed deluxe with a 15" speaker, how would the sound differ between a traditional tweed deluxe style open back cab, and a cab with a hole in the back, perhaps oval, as seen below? I assume the oval would only be effective if the speaker is centered in the cab, not offset.

When the size of the opening gets smaller relative to total volume, it becomes a semi open design AKA a ported design.
In this case the opening does not need to be centered behind the speaker, and can be on the sides of the cab.

I'm not sure if that Dumble cab falls into the ported design, but in true open back cabs there are other factors that will make the cab sound different, like baffle thickness, density, and stiffness; as well as perceived difference due to same model speakers actually sounding quite different due to age and amount of use they have had.

The proximity (and distance from walls) of two cabs being compared also strongly affects the perceived sound, and to really get a fair reading on how two different cabs sound you need to find two same model speakers that truly sound the same, and listen to the two cabs at the same angle from a great enough distance to not confuse proximity and angle.
If you've experimented with mic placement you'll have more evidence of how different a speaker can sound from different angles and locations.
When I liked V30s and had lots of them I found some V30 loaded cabs sounded a lot brighter than others, but then noticed that the brightness went with the speaker, not the cab.

If you've been playing loud electric guitar for a good number of years you may find that your left ear hears more or less treble than your right ear!

A lot of small cabs we encounter are made of very dense 3/4" MDF with rigid glued in baffles, where the materials and construction are influence the sound more than the "volume" of a cab which is open to the air and really has no effective volume at all, with regard to damping the cone vibration, or influencing and directing the sound from the back of the speaker.
The wall behind the cab has a great deal of influence on the sound!

 

[mRtINY]

Yes, a larger cabinet will have more extended bass response. When you measure the distance from the back of the driver around to the front, you'll know the half-wavelength where the front and rear soundwaves combine to reinforce the bass response. As you move to down in frequency, the point at which the 1/4 wavelength is as long as the path from front to back, is about as low as you will get useful bass output.

So, a wider, taller, or deeper open-back cabinet will have response to a lower frequency. For example, the Princeton cabinet is 18" wide and 8" deep. So, half the front baffle (9") plus the side (8") plus the diagonal distance from the center of the baffle to the rear corner ( ((8^2)+(9^2))^1/2 = ~12") gives us a pathlength of about 29".

So for frequency, 1/2 wavelength of 231Hz will be the strongest reinforcement and 1/4 wavelength of 115Hz is the lowest frequency supported (AKA - "cutoff"). And, if you've ever tried to get drop-D heavy overdrive sounds out of a princeton, you know that it sounds light on the bottom.....

Move up to my 5e3 cabinet at about 30" wide and 12" deep, and you get a peak at 113Hz and a cutoff of about 57Hz (which is why I struggle with a bass-heavy clean sound).


-tINY



http://www.hi-fiworld.co.uk/loudspe...udspeakers-open-baffles-and-bass-part-15.html