New cab on the way

[jonny deep]

I doubt that you need to go bigger for the iso box. Speaker do not really "move air".
What will happen is that the box will have its own resonant frequency (plus 3 major standing waves and all the harmonics!) which might be nice or nasty, lap of the Dieties mate!

Two major factors will govern sound leakage. Mechanical coupling of the cab to the box, so stand the cab on some soft foam to de-couple it from the base.
Then the box must be airtight and so you cannot use jacks for connecting speakers instead use XLR 4 (to avoid confusion with mics. SM57s are tough but they will not be happy with 20volts of amp!).

Dave.

Hey Dave - thanks for your input, maybe I'll stick with the box size as is, then. I'm confused as to why I can't use jacks - any cable, XLR or otherwise, will have to come out the box lid or maybe into a port installed into the wood - please can you explain, I think I'm missing something?

[ecc83]

Hey Dave - thanks for your input, maybe I'll stick with the box size as is, then. I'm confused as to why I can't use jacks - any cable, XLR or otherwise, will have to come out the box lid or maybe into a port installed into the wood - please can you explain, I think I'm missing something?

Well the neatest way to do things is to mount the connectors on a stout ally plate then take the wires thru the inner wall sealing them with plenty of builders white sealer (or snot as it is known in the trade here!) But any small air leaks can whistle or "chuff" and jacks will leak even with a plug inserted.

How were you thinking of rigging the mics? I would have short XLR "tails" in the cab wired out to said ally plate..Threes of course!

I have not built an iso cab (yet! Might make one at work.) but I have built many speaker cabs. Hi fi, line source, bass G, you name it. The connection thing applies for sealed cabs, as indeed it does getting audio thru a wall.

Dave.

[jonny deep]

Well the neatest way to do things is to mount the connectors on a stout ally plate then take the wires thru the inner wall sealing them with plenty of builders white sealer (or snot as it is known in the trade here!) But any small air leaks can whistle or "chuff" and jacks will leak even with a plug inserted.

How were you thinking of rigging the mics? I would have short XLR "tails" in the cab wired out to said ally plate..Threes of course!

I have not built an iso cab (yet! Might make one at work.) but I have built many speaker cabs. Hi fi, line source, bass G, you name it. The connection thing applies for sealed cabs, as indeed it does getting audio thru a wall.

Dave.

Ok, got you - thanks! I currently intend to run speaker and XLR mic cable between the lid and body of each box - there'll be rubber draught excluder glued onto the lid that will squish around the cable (and be generally useful for sealing the join), and I can drill partial holes to facilitate this further.

However, I had entertained the idea of installing XLR and jack ports on the sides of the boxes to avoid broken seals at the lid joint, but I'll avoid jacks if I do this. This thing will be out in the garage, so doesn't have to be perfectly silent, but I do need to attenuate the sound considerably.

I will require long speaker and XLR cables to run from the studio to the garage and back. I've read I can just use any two core cable (like cheap lamp cable) for the speaker cable. I guess I need proper XLR cable for the mic cable? Any ideas anyone?

[jonny deep]

Actually, I have a drawer full of XLR mic cables - I'll join them all together.

[jonny deep]

The cab arrived yesterday. It looks great and sounds really good too. I was surprised at how different the sound is to my 1x12 G12H30. I knew it would be different and I've watched those videos of speaker comparisons, but I was still surprised. I think the 2x12 cab size/configuration adds low end, plus the Greenback-type speaker is a darker speaker.

I opened up the back, expecting to see two 16ohm speakers in parallel, but was disappointed to find two 4 ohms in series. I was planning to switch one out with my 16 ohm G12H30 to give a different sound and two recording options, depending where I stick the mic. Much Googling later I find that there's no sensible way I can use these speakers, except as a pair in series. This was a bit disheartening and I was starting to think I'd paid for two useless speakers and would end up having to buy another pair to use this cab, or I'd have to get into an argument with the man who builds these to resolve it.

I phoned the guy this morning and he immediately suggests sending out a pair of new Celestion Greenbacks. I decided that as I'm getting new speakers, I'd get a Greenback and a V30 (the V30 is the same sensitivity as my G12H30, so might be more balanced, although I'm only going to use for recording in an iso-box). He's going to charge me an extra £25 as they are new speakers, which I'm more than happy with, especially considering I now get three speaker options. He'll cover the postage costs to send the new ones and get the pair of 4 ohm speakers collected.

So, big thanks to Paul at ZillaCabs! He did describe it to me as a parallel-wired 8 ohm cab, so immediately rectified the situation as best he could. Distance selling regulations here do protect me, but it's so nice to not have to argue and fight for those rights as one often has to with bigger companies. I am once again a happy camper .

(Sorry for the essay!)

[Greg_L]

Good deal! So you're gonna have what now? A V30 and a G12H-30 in one cab, and a Greenback in another?

[jonny deep]

Good deal! So you're gonna have what now? A V30 and a G12H-30 in one cab, and a Greenback in another?

If I put the V30 and G12H30 in the 2x12, then I'd get a balanced sound as they're both 100dB. I guess I'm going to experiment as to which speakers I like best to record and have those in the 2x12 in the iso box. The remaining speaker I'll keep in my 1x12 inside the house for practice and another recording option.

Which leads me to a question I've been meaning to ask. When you record one speaker in your 4x12, how much do you find the other speaker interferes with the recording (if you can tell at all)? If you have a louder speaker in the same cab, might this spill in or even overwhelm the sound, even when the quiter speaker is close-miced with an SM57?

[Greg_L]

If I put the V30 and G12H30 in the 2x12, then I'd get a balanced sound as they're both 100dB. I guess I'm going to experiment as to which speakers I like best to record and have those in the 2x12 in the iso box. The remaining speaker I'll keep in my 1x12 inside the house for practice and another recording option.

Which leads me to a question I've been meaning to ask. When you record one speaker in your 4x12, how much do you find the other speaker interferes with the recording (if you can tell at all)? If you have a louder speaker in the same cab, might this spill in or even overwhelm the sound, even when the quiter speaker is close-miced with an SM57?

The speakers in my 4x12 are all relatively the same efficiency/sensitivity/whatever you wanna call it. They don't interfere with eachother. If the speakers are mismatched and one or more is significantly louder than the others, the potential is there for some interference. But I think if you're close miking, the interference would be negligible. But just as a precaution, if I off-axis mic a speaker, I point the mic away from the others.

Having said that, my 2x12 V30 cab is louder than the 4x12 at low to moderate volumes. I can dial in my amp, and mic a Greenback or G12T-75 in my 4x12 and set the gain on the pre to record at a certain level. Fine, no problem. If I keep everything the same, but switch cabs and move the mic to the same exact spot on one of the V30's, it will track a few db's hotter. I have to turn my pre down about two clicks to get the V30's to track at the same level as the Greenbacks or G12T-75's with everything else being equal.

[jonny deep]

So my new speakers arrived yesterday . I just finished installing them and putting the cabs back together this morning. I haven't done any soldering since I was a kid when my dad taught me - seemed to go ok.

I've got the Greenback and G12H30 in the 2x12 and the V30 in the 1x12.

I've had a bit of a go on both cabs this morning: the 2x12 sounds great now, I much prefer to when it had the two Greenback clones in it. Also, the V30 sounds great in the 1x12. That said, none of these speakers are really run in yet (two are brand new), and I guess they'll get a bit warmer/darker as they get used.

I don't have the time to be experimenting with different combinations at the moment or for recording samples for you, I'm afraid. I have to pack the house to move in a couple of weeks and the studio gets packed first - otherwise, nothing gets done!

I will say this, though. It doesn't seem to matter how much money and time I spend on buying, building and modding gear - I'm still shit at playing guitar .