Bass cabinet

[boneless]

Hi, I'm new, and a total novice

Let me get straight to the point: I am fascinated by the idea of building a loudspeaker. I know that there are many cabs and many brands to choose from, but the idea of actually building a personal project quite intrigues me.

Anyway, I am, as I said, a total novice, so I'd like some help.

First of all, I'd like to choose from Ciare for the drivers: it's an Italian brand, and being domestic (for me, anyway) it would be very easy and cheap for me to find their products. They're also supposed to be very good, in terms of quality. I was looking at their PW line of drivers: http://www.ciare.com/consumer_en/pro...ofessional.htm
I may also look at other brands, anyway, ie. Eminence, RCF, B&C, whatever, although I'd like to stick to a high Q/P ratio (that is, spend as less money as possible )

My idea was of making a 2x12" cabinet, with the addition of a small midrange (ie. 5") instead of a tweeter, if someone is familiar with instrument amplification, you might know that for bass, unless you use modern techniques like slap, a midrange is probably best suited, since it sounds better with overdrive (which would sound a bit nasty with a tweeter, with its top-end sizzle). Am I going the right way?

I would obviously pad the inside of the cabinet with soundproofing panels or what you call 'em. Ah, and I'm undecided if opting for a sealed or a vented cabinet, since I'm not after ultralow bass, and actually I'm after a dry tone.

Thank you in advance!

[901Fixer]

If I may make a suggestion as a new fan of Hi-Fi myself, post what you are looking for the speaker to do or how you intend to use them and let the folks here help you with driver selection and cabinet build. I found this site and thought I knew a little bit about speakers from my dabbling with CarAudio, I was mistaken. Not only do things change over the years but members here have vast experience and keep up with all the new stuff. Take your time and consider what advice you are given and ask questions even if they seem simple. Understanding the abbreviations and acronyms is a task in itself. I'm sure there are many members here from near where you live and know how to build the best for the least.

Good luck and enjoy your project.

[PeteMcK]

speakers for an instrument aren't the same as a hi-fi speaker -
a 2x 12 box is ok, but if you want to add a small driver it will need to handle a lot of power- I'd try it at first without.

look at the frequency response of some typical guitar speakers, and chose drivers that are similar from the Ciare range.
These typically have a peak in the upper mids - so you may not need the small driver if you make the right choice

For instruments, don't add any padding, and for dry tone , use a sealed box

[Brett]

Nip over to www.talkbass.com and in the bass guitar amp section, there is a number of DIY threads with an Eminence 3015LF and an 18Sound 6ND410. The poster's name is greenboy and it's called the "fearful".

Before I stopped playing out I'd intended to build something similar. There's a lot of detail there and it might give some inspiration.

[boneless]

Hello to everyone,

after reading some stuff on the Internet, and on Talkbass, I eventually made my own design.

Here is a (rough) "blueprint" of my own cabinet:



There is a mistake in the description, I am actually planning to use a 4th order Butterworth highpass on the midrange. I'm not planning to filter the woofers.

Here is the data regarding:

- the 12" woofer (Beyma SM212): http://profesional.beyma.com/ingles/pdf/SM-212.pdf
- the 6.5" midrange (Beyma 6MI90): http://profesional.beyma.com/ingles/pdf/6MI90.pdf

Here is the WinISD project regarding the 2 12" woofers: http://www.gospel.bo.it/albums/userp...xsm212_wpr.zip

Cabinet is 122 L, tuned to approx. 39Hz. The midrange would be placed in its own sealed cabinet, approx. 5-6 L. Adding driver volume, the sealed midrange section, and overestimating the end results for safety, I have ended with a 142 litre cabinet.

The cab won't probably be terribly loud, since the drivers aren't really very sensitive (96dB for the 12" drivers, 98dB for the midrange but the cabinet will probably have a final sensibility of 98-100dB, which isn't TOO bad, I suppose. I'm not after loudness, anyway. I am using a 450W @ 4 ohms amplifier that probably has never been pushed once in its life.
I am actually making all the calculations at 400W predicted power. Which is probably even too much for me. I don't play in a really loud band, so I don't think I'll ever need it. Anyway, cone excursion, port air velocity and frequency range are all under control.

My main concern, though, is impedance. My amplifier is limited at 4 ohms minimum impedance. This is the impedance curve for the woofers:



Minimum impedance is approx. 5.8 ohms (for each driver, I think). I know that nominal impedance isn't really a very representative value, but would I end with a 4 ohm cab, considering that I'm also mounting a midrange? I don't really want to filter the woofers, for simplicity (of course, I'm going to install an attenuator on the midrange). I'm also prepared to accept a slightly higher impedance rating (4 to 6 ohms maximum), I'm not concerned about the amplifier, since it has a protection circuit and nothing would probably happen, but you know, I'd like to be able to actually use the cabinet

Thanks in advance!

[boneless]

Bump!

[infinia]

If your amp is designed to handle 4 ohms nominal you should be OK even if your bass speaker is 3 ohms min. But the midrange will even load that down further so you should think about a proper lowpass filter for the bass ie series inductor.