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Replacement speakers for an existing 2 x12?
- Thread starter boristhespider7
- Start date
Thanks for the advice....much appreciated from all of you
Is the Delta Pro 12a the same as the Delta 12a? The Delta 12a is v reasonable priced in Europe (only about £80/each) so sounds like it would be a good one to try. I don't think i would make much selling this cab and buying another, besides i like the look and shape of this cab...really easy to carry
Ahh...just looked it up on the eminence site...Pro and standard delta speakers are quite different. Xmax on the Pro is much higher
The 12A is a fine driver of medium sensitivity. The Pro12A is significantly more sensitive, has a smoother and more extended response, and a lower Qts (allowing a less peaked bass response in smaller cabinets - like this one).
That is a crazy long port, are you sure you are not talking about the width?
The port is a long slot the full length of the cab...i think they are known as shelf ports. You can just about make it out in the photo
You need to provide the depth of the port. That is just as important as the other two dimensions.
OK, finally got round to measuring the inside of the port. The shelf goes into the cab for a depth of 20cm. Does that help?
fb: 37Hz
As fb is very low and rather close to characteristic of sealed cabs I suggest loudspeaker Qts >> 0.4
To be honest but fb 37Hz looks like a dummy port (or HiFi port) rather then a reasonable port for vented application as bass guitar cab.
As fb is very low and rather close to characteristic of sealed cabs I suggest loudspeaker Qts >> 0.4
To be honest but fb 37Hz looks like a dummy port (or HiFi port) rather then a reasonable port for vented application as bass guitar cab.
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The Eminence Delta 12LFA will meet your design goals and budget. In your box, with the stock vent, it will yield an F3 of around 56 Hz and exhibit mild bass peaking (+1.6 db @105 Hz). The peaking will add some punch and richness. A pair of them will have a midband sensitivity of about 97.5db/w/m, 3-4 db higher than the stock drivers.
Optimum tuning is a few Hz higher than the stock vent produces, but the stock tuning will be nearly as good. However, the stock vent will produce chuffing with the new drivers (due to their greater displacement). Further, the turbulence will result in reduced cab resonance (= less effective loading). I suggest that you abandon the stock vent - seal it off - and add two 4 inch diameter by 4 1/2 inch long port tubes. You may need to add some bracing, as the cab was designed for relatively light duty use.
Optimum tuning is a few Hz higher than the stock vent produces, but the stock tuning will be nearly as good. However, the stock vent will produce chuffing with the new drivers (due to their greater displacement). Further, the turbulence will result in reduced cab resonance (= less effective loading). I suggest that you abandon the stock vent - seal it off - and add two 4 inch diameter by 4 1/2 inch long port tubes. You may need to add some bracing, as the cab was designed for relatively light duty use.
Wow, thanks guys...i knew someone out that had the tech know how!
I'm really keen to keep the cab box unmodded so simply a drop in speaker placement that is fully reversible. Not sure i understand all of this: "Further, the turbulence will result in reduced cab resonance (= less effective loading)" Does this mean some of the lower end will be effectively cancelled out by turbulence?
I'm really keen to keep the cab box unmodded so simply a drop in speaker placement that is fully reversible. Not sure i understand all of this: "Further, the turbulence will result in reduced cab resonance (= less effective loading)" Does this mean some of the lower end will be effectively cancelled out by turbulence?
ANY drivers that will come close to doing what you want will cause chuffing in that narrow vent. The chuffing is the sound of turbulent air flow in the vent. It will decrease the loading of the drivers. There will be less control of cone motion, resulting in lower excursion limited power handling. The drivers will be more easily farted out.
Note that just about the biggest mod you can make to a cab (short of taking a chain saw to it) is to change out the drivers.
I've got a pair of Delta Pro 12A's in a 4cf box and can attest they work well for bass. That cab sounds better than my GK NEO cabs. They don't like low tuning, however. After a little trial end error, I found they work best in an enclosure tuned to about 54 or 55 Hz. Any lower and you get muddy bass and really low power handling.
I previously had those same drivers in a cab about 3.3 cf and they sounded great in that one too. I only replaced that cabinet because I completely overbuilt it using 1" thick MDF and it weighed about 110 pounds.
Many years ago I tried to get loudspeakers for a 212 cab tuned to fb around 40Hz.
After several inefficient trial and errors I gave up and tuned the cab to around 50Hz according on driver needs.
After several inefficient trial and errors I gave up and tuned the cab to around 50Hz according on driver needs.
So am i right in thinking that i have 2 options if go with the Delta 12LFA?
Seal the vent up? (will this work OK if i simply block it off? Or would i have to cut the shelf off first and then seal the gap?)
Shorten the port to 7-11cm?
I'd look for a different loudspeaker first.
Or finally let the cab as is. Because fb is low means mechanical power handling is already improved.
To me it makes no sense to improve "mechanical" power handling by a higher cab tuning but different loudspeaker.
In different words, you may try to increase power handling with different loudspeakers but higher tuning of the cab likely will turn it all upside down.
Or finally let the cab as is. Because fb is low means mechanical power handling is already improved.
To me it makes no sense to improve "mechanical" power handling by a higher cab tuning but different loudspeaker.
In different words, you may try to increase power handling with different loudspeakers but higher tuning of the cab likely will turn it all upside down.
