Cabinet project: How do I chose speakers that 'Match'?

[Dave]

I’m going to be building (or buying) two cabs to go with with my Blackstar HT5. The minimum I want is a 15� cab on the bottom and 12� cab on top in a stack. I’m tempted to do a cab containing both a 12� and a 10� speaker a’la Steve Albini for no other reason than I’m a bedroom fanboi however I don’t know if this would have any benefit. Before I even get to the actual building process I want to identify the speakers I’m going to use. I don’t know how to ‘match’ speakers of different sizes or how to match them to the cab outputs on the HT5 so hoping you guys can point me in the right direction.

I do currently have the Orange 1x12� so it could be that I simply build a 1x15� to match that. Not sure. Ideally I’d like to make it a bit of a creative project including tolexing or covering the cabs in leather-esque vinyl of a cool colour.

Sooooo:

Is there any reason I couldn’t have the 12 AND 10 inch in one cab, as well as the 15� cab? How do I match the speakers to work together well with each other and also with the HT5?

Does having a 10� in addition to a 12� provide a benefit like having a different range of frequencies or owt? Obviously Albini tops it all with a PA tweeter but I’m not THAT arsed.

[NickS]

Essentially I want to creat version of Steve ALbini's stack. He has two cabs, the bottom one is a 15" (also with a tweeter horn in, though that's not really needed in my case) and the top cab is a 12" and a 10".

I could just go with a 15" and 12" as i do at the moment however the 15" is quieter than the 12" and the cabs won't sit on each other. My idea is to buy or build two cabs that work well together and get at last the 12" and the 15" matching. A couple of questions though:

How do I match a 15 with the 12 (and possibly 10)

Getting cabs to match; hmm. Speakers have different sensitivities (usually specifed in dB per watt or milliwatt) depending on their construction - kind of magnet, stiffness of the suspension, etc., so getting a balance between different makes, models or sizes is likely to involve a bit of trial and error. You can use an attenuator to reduce the power going through a particular speaker (some speakers have one on the tweeter) but you are then (obviously) wasting power, and they're not cheap.

Why do you think he uses a 12 and a 10? is there something about the frewquency response that makes this a good idea?

Generally the smaller the speaker the higher the resonant frequency (lower mass for given suspension stiffness/compliance) so it could be he's looking to avoid a honk at a particular frequency. Smaller speakers also tend to reproduce higher frequencies better and larger speakers lower frequencies better (not necessarily always the case, my Altec 15" is voiced for guitar rather than bass, unfortunately). Hi-fi speaker cabinets are generally designed to try and eliminate or make controlled use of the resonance ("tightly-controlled bottom end", hur hur)

Would I be able to have that amount of speakers with my HT 5? I can run two cabs but don't know how that translates to actual speakers/ohms/matching outputs etc.

The specs for the HT 5 are:

5 watts into either 1x8 ohm, 2x16 ohm or 1x16 ohm.

What are the impedances of the 15" and 12" cabs you have at the moment - 16 ohms each? If you have teh exact models it might also be able to take a look at the sensitivity. You certainly could have 3 speakers - one way would be to have 8 ohm 12" and 8 ohm 10" in one cab wired in series, 16 ohm 15" in the other. That way half the power would go to the 15" and a quarter to each of the 12" and 10". How that would actually sound.... don't know.

[George]

i've heard of people using mixtures of different speakers of the same size, but where you have to be careful is mixing different sizes. apparently.

[h8mtv]

I'd make sure they are same ohm and pretty close SPL rating and you should be good.

[Dave]

one way would be to have 8 ohm 12" and 8 ohm 10" in one cab wired in series, 16 ohm 15" in the other. That way half the power would go to the 15" and a quarter to each of the 12" and 10". How that would actually sound.... don't know.

Thanks Nick (and all) for all the sagely wisdom and going into the details. I think I could get blinded by the details and since a truly "try evryhting until works" approach is not financially doable, I'll start off by scouting around for the combination of Ohms above and then try and pin down the other factors based on the speaker specs.

nick - I'll pull my cabs out of their abode at the weekend and get the figures you asked for.