Replacement speaker for an old Acoustic 136 cabinet?

[JimmyM]

What you have is a very different cabinet than the one in the picture you posted initially. That's what drove many of the comments.

I still think a Delta would work for it Might even be better in that one. That looks to be around the same size as a B-15 cab, and the Delta crushes in my B-15 cabs.

 

[Rick James]

As I stated, the picture in the OP was a stock photo not the actual one I own.

That cab is probably tuned to around 65-70 hz, so with any speaker it's going to have a big response hump around 100 hz and weak lows. It could be rebuilt with ducts on the ports, but all things considered I'd seal the ports and use a BP1525, which is made to work well in small sealed boxes.

 

[agedhorse]

I still think a Delta would work for it Might even be better in that one. That looks to be around the same size as a B-15 cab, and the Delta crushes in my B-15 cabs.

Maybe so. I would do the math and see.

 

[BogeyBass]

yes indeed the eminence 154 is very dark and sensitivity is low around 96 db I think so the extra wattage the 4ohm load gives you would bring about the same sound pressure as a 98dB 8ohm.

likewise there is rare EV speakers that have 101dB and the eminence delta pro 15a does 101dB and currently available.

high sensitivity is extremely useful for single speaker applications.

but everyone seems to miss the much brighter 4ohm speaker eminence has which also has a decent 98db sensitivity

the higher budget neo
eminence basslite C2515

 

[agedhorse]

Which delta pro achieves 101db average sensitivity? Let me rephrase this... which one achieves 101+ dB average over the bass guitar range. Look closely at the raw response curve for this drive and you will see that it's less than 100dB all the way up to 800Hz.

That said, the voicing might make it a pretty good choice for a "no tweeter" older school cabinet and the tradeoff that makes it aggressive above 1.5kHz also tends to limit the low frequency performance capabilities. For a smaller amp, and if the response fits the player's taste, it might be ok (but not 101dB ok)

Incidentally, the EVM-15L share many of these same trade-offs.

 

[BogeyBass]

the eminence delta pro 15a
Speaker Detail | Eminence Speaker

from 100Hz to 1k the speaker has
100 dB

from 1k to 4k the speaker has 105 dB

so yes it's average sensitivity is 101.6 dB as rated by the manufacturer

the low end in 45Hz range will be around 96 to 98 which will still outperform any 98dB speaker because those speakers will have low end performance in the 94dB
range

to achieve low end performance we use the typical reflex enclosure or ported enclosure to accent low end performance.

to further extend the output of a reflex enclosure you use a horn loaded/reflex
cabinet. which is what the 136 combo uses a short path rear lloaded horn which achieves same impedance curve as a typical reflex cabinet at 45Hz
it will add a extra 2 to 3dBm in a very small bandwidth from 45Hz to 100hz which gives a lower f3 than what a standard reflex cabinet would at the same 45Hz tuning.

absolutely the end all of reflex cabinets
one of the best reflex ccabinets invented music man electro voice and Yamaha have all produced reflex horn loaded cabinets and Yamaha produced a monster 215 reflex horn loaded cabinet which produces amazing bass output when modern more durable drivers are used.

 

[agedhorse]

the eminence delta pro 15a
Speaker Detail | Eminence Speaker

from 100Hz to 1k the speaker has
100 dB

from 1k to 4k the speaker has 105 dB

so yes it's average sensitivity is 101.6 dB as rated by the manufacturer

the low end in 45Hz range will be around 96 to 98 which will still outperform any 98dB speaker because those speakers will have low end performance in the 94dB
range

Yes, I am very familiar with this speaker... the average sensitivity spec for Eminence speakers is based on full range program signal (such as for PA, or even guitar), not bass guitar. (IIR, it's based on 100Hz - 5kHz) For bass guitar, the sensitivity from 1kHz to 4kHz doesn't matter other than for midrange voicing. For practical, real world reasons the sensitivity from ~50Hz-1kHz is MUCH more representative of what can be expected for bass guitar applications though it obviously will result in lower numbers (like ~98dB).

Specified bandwidth is critical when comparing speaker sensitivity, otherwise a 5" midrange driver with 102dB sensitivity from 1kHz to 4kHz would APPEAR to be a superior performer than a 15" driver with 97dB but measured from 50Hz to 1kHz for bass guitar applications. Now for midrange applications the preference might be reversed, but this is important application specific stuff IMO.

Numbers mean nothing without considering how they are defined, in this case it's the elephant in the room.