Cab and Speaker recommendations for Keyboard amplifier

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi all, I'm planning to build an amp for my keyboardist, and I'm having trouble deciding what kind of speaker and cab would be appropriate for this task!

I suppose it needs to be at least a two-way system and be able to handle around 100W with a nominal impedance 8ohm.

I've done some sub box design for car audio but I've never put together anything for home or musician audio.

Does anyone have any suggestions?

Thanks!
 
A question of portability: Is it to be a portable install or is it a fixed install?
The answer may affect quality

A question of circuit breakers: If portable use, is the venue random, such as places where an extension cord and regular outlet are used (where you can't yank out 5a of the 15a max just for the keyboard)?
The answer may affect speaker driver and amplifier selection

A question of range: Is the keyboard used over the entire range of a large pipe organ, or the range of a full size piano, or the range of a 61 note keyboard?
The answer affects the size of the speaker (proportional to the range of the instrument)

A question of power (distance to audience applies):
100 watts? Of what? The answer affects speaker driver selection. Okay, really, I'm just saying that you might want to look at this:

87db speaker with 128w = 108db
92db speaker with 50w = 108db
98db speaker with 15w = 108db

92db speaker with 128w = 113db

98db speaker with 128w = 119db

In all cases, those are peaks.
Subtract 24db for approximate live sound output.

For travelling use, you can see that the huge size 98db speaker doesn't need much amplifier power, and that might be more important than speaker size if the entire band is plugged into just one outlet.

And, a very general rule of thumb: The reason that pianos are larger than toasters is for having bass sounds fit inside the piano (the wave is a large size). So, for a realistic sound, each speaker would be at least half the size of a piano. ;)

Another question: Is this a keyboard "monitor" (helps keyboardist hear over the guitar player), or is it a keyboard "main" used for sound reproduction to an audience?

EDIT:
Also consider that it takes a speaker about this big: http://www.parts-express.com/projectshowcase/indexn.cfm?project=MagnaCumLaude to even come close to the performance of "Open Back" DJ headphones.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.