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Can Somebody Help Me Design a Cab? Please :)

#21
The 3015LF is not the driver I would recommend for bass guitar without a mid driver or at least a HF driver that can be safely crossed below about 2.5kHz, and you will probably want to deal with the huge 2kHz peak... which then falls like a rock above 2.5khz. The network required to tame that honky peak is going to cost more than getting a better suited driver. The Kappa 15A is no better IMO.

You might look at the KappaLite 3015 is a FAR more suitable driver for bass guitar (no comparison really) and you MAY be able to get away without a horn too. It would still require a suitable enclosure design.

https://www.eminence.com/pdf/Kappalite_3015.pdf
 
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#22
deadinameadow said:
but I need to find the dimensions and all that of my cab but idk what to do with that info once I have it. Idk how to calculate the tuning of the port or what the current speakers specs are
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Measure interior dimensions. Length, width and height in inches. Then L x W x H divided by 1728 (a cubic ft. 12" x 12" x 12" = 1,728). For example if your interior dimensions are 24"x 20" x 12" that would be 24 x 20 x 12 = 5760 divided by 1728 = 3.333333 so 3.33 Cubic ft. easy yes?
 
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#26
deadinameadow said:
I've recently ordered an Eminence Kappa 15LFA driver and i would like to build a cabinet that is perfect for this speaker...
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If you decide to go ahead with that woofer, I would suggest about 2.3 cubic feet gross internal volume (this means you don't have to subtract for the space occupied by the woofer and ports), tuned to about 50 Hz by two 4" diameter ports, each about 9 inches long.

If you are open to using a different woofer, my first choice would be the Kappalite 3015 (non-LF) recommended by agedhorse. I'd suggest 2.8 cubic feet gross internal volume and two 4" diameter ports each 5.5 inches long, again tuning to the 50 Hz ballpark. This woofer is of course considerably more expensive.

Other possibilities are the Legend CA154 and CB158, both of which will work well in the same box as the Kappalite.

These box sizes and tuning frequencies assume that you tune to low-B. If you tune higher than that, we can theoretically reduce the box size and/or raise the tuning frequency.

deadinameadow said:
One of these days though, I will build a cabinet and it will be awesome. Just need to do more research I guess
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I was an amateur speaker builder for about 25 years before I "turned pro". It's a great hobby, especially if it also supports your music career/passion.

I suggest "The Loudspeaker Design Cookbook", by Vance Dickason. And a good speaker modelling program, that can be quite educational as well. You can model known designs (or come close enough) to get a feel for "where the goal posts are" for designing a bass cab. Personally, my low-end target is the first overtone of low-B, which is 62 Hz. The boxes I suggest above are roughly -3 dB at 62 Hz, so they have a decent but not huge low-B.
 
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#28
Here is my design

5galspeaker2.jpg
 
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#29
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#30
I was building a box some years ago, though my aim was different - I wanted to build even smaller box than what was on the market, to be able to travel with double bass in public transport. I remember that there were two main problems:
1. design the box, and especially the bass port
2. cut the MDF board precisely enough

To do 1., you need information. I'd start here: The Subwoofer DIY Page , eventually you'll need a free computing app WinISD Invalid Link Removed

To do 2., I managed to interest a fellow carpenter with it. You can't really do it without precise cutting machinery I'm afraid. Glue it together is simple, just be patient.

I did two boxes - 8" and then 6" - both works great, and I never heard anybody to say that it plays badly (on the contrary!). Since I learned to measure the sound qualities, I know it does exactly what it should do.
You learn a lot in this quest, and reveal that some important truths about sound the bassplayers believe are a result of marketing. I say go for it.
 
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#33
deadinameadow said:
How do I find the perfect replacement speaker? My cabinet is from the 70s, no information on it anywhere, I'd rather buy a driver that would be the best replacement in this cabinet than build a new one but if I can't get this returned then idk, but I need to find the dimensions and all that of my cab but idk what to do with that info once I have it. Idk how to calculate the tuning of the port or what the current speakers specs are
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That looks familiar...what brand of cab is that, OP? If it's a Kasino Snake Eyes 2x15 I may have some good news for you.
 
#37
Kappa LFA doesnt work very well in small box. Its boomy

Likewise doesnt work well high tuned unless its highpassed for midbass. Absolutely not the application for bass guitar.

Guarantee to get a " muddy slow" 15 with high tuned kappa in the 50s. Reflex eats it up and it aint got no top end. Putting it in small box for power handling and high tuning is no no.

This woofer does well in classic large box for 15. 3.8 to 4 cubic feet tuned low near fs at 40 hz

Only way around a small box with low tuning is a reflex bass shelf.

Negative 6 db extended bass shelf will intentionally use small box to create the top portion of the shelf response. Then tune way way below fs to get the bass shelf. If you enter the driver into winsd it has auto calculation for -6 ebs. Smaller box could help and it wont be typical flubber dubber tuned low. High tuned box at 2.5 lol thats gurantee poopy doopy.

Otherwise it is what it is. Live with it in a typical BB3 . power handling is what it is. It will autually have snap in good old 3.8 at 40hz

Why dont people just make life easy and do a matched pair in a 2x15. 2.5 to 2.8 per driver is ok. But you need the right woofer. The ever so classic 5 cubic foot 2x15 at 40hz lives on and its just as generic as a small block chevy with same old cam and duration thats worked for million years. But guys keep trying reinvent the wheel...
 
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