High efficiency BASS

[otlnoob]

so I am sure this has been asked before, but here goes.

Can one affect sensitivity/efficiency by wiring two of the same driver differently. If so how and does that affect the fas needed for the cabinet?

If not, can anyone recommend a high efficiency driver 8" and under - prefer 6.5" with efficiency over 95.

Thanks

[Helmuth]

Originally Posted by otlnoob

so I am sure this has been asked before, but here goes.

Can one affect sensitivity/efficiency by wiring two of the same driver differently. If so how and does that affect the fas needed for the cabinet?

If not, can anyone recommend a high efficiency driver 8" and under - prefer 6.5" with efficiency over 95.

Thanks

How do you mean different polarity?

Or a closed band pass with 2 drivers to reduce the box volume by factor 2.

efficiency can be increased by acoustic coupling "line array".

[doug20]

Wiring does not change anything about the speaker sensitivity. It just will change the impedance of the set of speakers.

As for speakers with sensitivity, what are your goals???

You should know that 6.5" drivers that are > 95 dB sensivity will not do any sort of bass for you. Its a simple fact of science, you sacrific low frequencies to get more sensivitiy, generally the Xmax gets really, really short. To go low with high sensitivity you need to increase the surface area. IE 15" TD15M is a great driver from 60Hz to 1000Hz.


FWIW, I own these 6.5" >95dB drivders.... PHL1120, 18sound 6ND410, b&c 6md38. I have matched them all to my Neopro5i ribbons. I like the PHL1120 the best but the B&C has great value. The 6ND410 is purely a midbass with great sensitivity, Im considering it as a mid range match to small round waveguide horn but that is a project or two down the road.

btw, the 6md38 is pretty great value, see measurements here Zaph|Audio

Again, the important question, what is your goal here?

[badman]

Originally Posted by doug20

Wiring does not change anything about the speaker sensitivity. It just will change the impedance of the set of speakers.

Not exactly accurate- if you're wiring the voicecoils differently and changing impedance on a multicoil speaker, or multiple drivers in series/parallel/series-parallel, the sensitivity is always affected. What doesn't change is the efficiency. Voltage vs. Power, Sensitivity vs. Efficiency.

[doug20]

thanks for the correction, efficiency and sensitivity does get mixed up.

[ScottG]

Originally Posted by doug20

thanks for the correction, efficiency and sensitivity does get mixed up.

..plus efficiency is almost never expressed as efficiency, but rather at a 1 watt 1 meter spl average (..often centered at 1 kHz).

Real efficiency is downright depressing.

For the OP:

GENERALLY (all else equal) it is:

1. for every doubling of drivers = 3db gain.
2. for every doubling of parallel connection = 3db gain.
3. for every doubling of series connection = 3db loss.

( 2 & 3 rely on a "voltage" amplifier capable of driving the impedance.)