need some help from the bass players

[xstephanx]

Im going to chase my 11 year old dream and finally get a bass. I decided to build my own amp. Im fine with modelling stuff, i just need to know certain things

How low should a bass amp be able to play? (eg"it should be able to play -6db at 40hz")

will two 15s each getting 100 watts do the trick?

thanks all!

[BassAwdyO]

I dont personally play much bass, but my dad does in a band.

I'd make sure it's flat to at least the lowest string on a 5 string which if I remember correctly is 31hz

High frequency extension is also vital due to the many harmonics produced by string plucking(slapping picking or whatever style you choose to play). I dont know a specific cutoff there, but I'm sure 10k is more than adequate and you can probably get away with Alot less.

[leadbelly]

Bad choice for forum, as a bass rig is far from either being a subwoofer or made with subwoofer drivers.

There's some good threads; here's one:

Building a bass amp and speaker (cont...)

[xstephanx]

sorry, and the bass would be 4 string.

but if the lowest fundamental is 31hz i might be in some trouble, there arent a lot of woofers that will play up to 3khz and drop down to 30hz. within my price range that is.

looks like getting that much LF might be harder than i thought...

[simon5]

If the bass is a 4 string, then you can make it flat to ~40 Hz.
I would use a large ported enclosure with a nice Pro woofer or a coaxial. You need to be flat to 40 Hz if you plan to play outdoors or in very large rooms. If it's for a small room, you could use a shallow rolloff from 200 Hz to about -6 dB at 40 Hz I guess.

[leadbelly]

Originally posted by xstephanx
but if the lowest fundamental is 31hz i might be in some trouble, there arent a lot of woofers that will play up to 3khz and drop down to 30hz. within my price range that is.

Well, you haven't said what your price range is, but I find that statement hard to believe. For budget applications, you can just use a PA speaker instead of a proper bass speaker, and PA speakers are available very cheaply, there are many cheap 15" PA speakers out there. Personally, I would prefer a smaller brand name bass speaker to a bigger no-name PA speaker, but that's just my opinion.

[BassAwdyO]

Pro drivers are probably the way to go.

If you have alot of money to spend on it, and I'm guessing you dont because you said it was a tight budge, you could use a few extremis midwoofers from adire. I think those would be killer for a bass amp. 30hz-5khz but at $100 apeice and 86db efficiency they might not be the best option.

[DSP_Geek]

4 string bass lowest note is low E, 41.2 Hz. 5 strings go lower, but if it's your first instrument I guess you'll be sticking with something known.


Francois.

[theNoid]

Originally posted by xstephanx
Im going to chase my 11 year old dream and finally get a bass. I decided to build my own amp. Im fine with modelling stuff, i just need to know certain things

How low should a bass amp be able to play? (eg"it should be able to play -6db at 40hz")

will two 15s each getting 100 watts do the trick?

thanks all!

Is this going to be for practice, or do you plan to do some shows right out of the blocks? If for practice, then there is no reason for large dual-15" cabs man, not even close.

If I may make a suggestion, while you are learning, and getting started, go with the KISS approach here. Build yourself a cabinet for the Eminence Legend B102 10" Bass Guitar driver and have at it. This driver is an excellent learner/practive driver and covers the top end well enough to where you don't really need the tweet.

http://www.partsexpress.com/pe/pshow...95&ctab=2#Tabs

If, after you learn to play really well, or at least well enough to warrant building anything bigger, then by all means, go bigger and badder.

What amp/head are you panning on using for said learning/practice set-up?

Noidster

[Ahmad_tbp]

hi .. i m playin bass and i m tryin to build a cab myself ...
here is my forum u ll find very useful info there : Subwoofer construction help plzz :(
.. the lowest string on a five strings bass is about 31 hz ... but u don need to find a woofer to handle 31 hz .. cuz in the most of famous ampeg cabs the response freq is startin at 55 hz ! ..
lol . it s concern to what kind of music u wanna play ...
so if it s hard for u to find a woofer to handle 31 hz forget it ... just try to find some good driver to handle 55 hz up ... i suggest EMINENCE ( eminence kappa or kappa pro )... cuz some great company like ampeg use the eminence drivers in their cab ! ...
but if u still want to have a full range respond , use a 18" or 15" driver w a large cab for low freq and a 4*10" cab for harmonics ( and of course a horn driver if u want a full range ) , cuz a 18" driver or 15" cant respond well in harmonics ...
if u wanna use this amp for practice use 2*10" or 2*12" cab at last and they don need to handle 31 hz , MOST of the famous bass combos like marshal ampeg , peavy , etc ...use one 10 or 12 " driver in their cabs ,and they never handle lower than 60 or 50 hz cuz it s really not necessary ... i m playin my ibanez sr3005 prestige model bass in my computer speakers !!! lol ,...
so don worry to handle 31 hz ... and here s the bass preamp i m usin for amp , it s a reall bass amp that made by a real bassist ! lol : http://www.albertkreuzer.com/start.htm ( bass jfet pre amp ) u ll not disapointed ...
so just search a lottttttt ... and try to understand how the famous manufacturer build their cabs and how is their freq response ...
if u think i can help u , just tell me .. i ll help u as i can , CUZ I REALLY KNOW HOW U DREAM FOR A BASS AND AN AMP AND WHAT U FEEL NOW ...