best speakers for open backed cabs??

[jdavis]

I have an old Pacific Woodworks 4x12 cabinet I'm thinking of upgrading with new speakers. I bought it in 1987 and it still has the celestion GM12-70 watt speakers it came with. The cab has seperate inputs for each side, so it is essentially 2 2x12 cabs. The bottoms are Thiele ported and the tops are 1/4 open backed. I'm leaning heavily towards EV speakers for the bottoms but I'm not sure of the best speaker to use for an open backed cabinet. Anyone have any suggestions? I have built 4 1x12 cabs using the measurements of the Theile ported bottom of my 4x12. I have 2 loaded w/ 25 watt Greenbacks and 2 loaded w/ GT12 75 watt speaks. These are both great in ported cabs but I'm not sure if they would be what I'm looking for in an open backed application. Your thoughts....?????

[BrianGT]

I use open back Matamp cabs and I use Celestion Century Vintage speakers.
Forgetting that they are really light in weight they are a great speaker.....very well balanced in frequency and don't over power with any nasty frequencies.
They sound far better than a V30 clean and crunch up just as good.

I see you have two TT's....I also use these speakers in my RV50 combo
and they have given it a nicer clean sound.

One caveat though.......they do take longer to break in but once they do the top end mellows and the bass becomes stronger and rounder.
I can say this with confidence because I own 8 of them and they are in various states of being broken in!!:D

[a.hun]

Very difficult question(s) as there are so many possibilities, so many variables.

For starters I'm not quite sure what your Krank sounds like, or if you'll even be using it with the cab or just the Oranges. But some speakers work with some amps much better than others. (And IMO the G12T75 is one that doesn't suit Oranges that well.)

Quite apart from tone (and open / closed back considerations), and the need to think about impedances of course, the two other main factors with speakers are power handling and efficiency.

Power handling is <i>fairly</i> easy. Just make sure that the amp is never going to overpower the speaker. Any higher speaker power handling rating isn't a problem, only too low a rating.
But with some speakers, like your 25 watt G12Ms, pushing them hard will get you lots of cone break up, (distortion), which may or may not be desired. If desired you'll want to make sure thay see enough power to cause that. If not you'll need to make sure they don't.
Other speakers tend to stay clean much closer to their rated power handling and break up usually isn't a (desired or actual) factor. EVs typically have high power handling and stay very clean up to high power levels.

Also do you want to have similar power handling capabilities for the two sections of the cab or not? Are you likely to want to use the cab with much higher powered amps in the future or not?

Speaker efficiency ('loudness') can be tricky. The rating is in
dB/w/m
basically meaning the sound pressure level (volume) in decibels which you'll get with 1 watt amp power measured at 1 metre distance.
Basically how loud a speaker or cab is for a given amp power.
But it isn't an absolute guide to how loud the speaker will sound with any given amp. For starters (apart from Eminence) most manufacturers only rate the efficiency for a single frequency (usually 1kHz). Some lower rated speakers (like the 98dB G12M25) can sound louder than their overall rating because much of their energy is put out in the midrange where our ears are most sensitive. Different guitar amps put out different frequencies more or less strongly.

Speakers like the EVs you are thinking about tend to be <u>extremely</u> efficient, meaning lots of volume for a given power input. (The G12T75s are a good bit less efficient for example.) So if you want the speakers in the open section to match those in volume you'll need something that can really punch out the decibels.

What do you want tonally from the cab? Do you want different contrasting sounds you could maybe mic up separately. Or different contrsting sounds you'll hear well from out front? (If primarily for mic'ing then efficiency differences matter much less as you can tweak the mic'd signal levels to balance them via the PA etc. Acoustically though out front you'd hardly hear the contribution from less efficient speakers in an open backed section. Though maybe more so from close by and beside the cab. Technically of course the Thiele sections arent 'closed' either, they are 'ported' which will give a much wider bass spread than a sealed cab.

As to which speakers work best in open cabs compared to closed ones that is an almost impossible question to answer. Different ears will tell different stories on that. The main limitation I can think of is that if pushing speakers very close to their power handling limit you are better off putting them in sealed cabs. That will give the cones some support from the air sealed in the cab, and that dampening effect helps prevent excess cone travel. But again you don't have any sealed cab sections here...

So why are you thinking of using EVs? What do you want from the cab overall? What do you want from the two main sections? Are you wanting an ultra efficient cab for low powered amps / high powered amps / both? Are you mainly interested in how it is going to sound acoustically or are you mainly going to be mic'ing up for live / recording use?

What are your own thoughts / wishes / needs really...?


aNDyH.

[irish_admiral]

Lots of good advice & questions from Andy above there to which i'll add a couple.

What sort of music are you intending to play? Using which guitars, distorted sounds, scooped sounds, mid-heavy? Any clean blues or jazz? What sort of sound do you have in your mind when you're thinking about this?

[Tibor]

i use 2 EV12L in my Orange Overdrive 120 Combo...and they stay clean even with the Amp turned full UP!...some people who played over my amp don't like the analythic (my english isn't the best!) sound of the amp...it shows off all of your playing mistakes...and they are extremly effective the amp now seems double loudes than with the G12-T75 which it came with (yes it was a 90's reissue Combo BUT I LIKE IT!) REALY NEGATIVE IS THE WEIGHT!!! You carry around 30 pounds more than before!

before the speakers went to the combo i used them in a closed 2x12 cabinet and i didn't like it looking back...the tend to be sounding harsh and trebly...in the open cab they can "breath" more freely...