Efficeincy Question

[mitchyz250f]

Let say I have 2 midbass speakers that have the exact same efficeincy. Speaker 'a' is flat to 50hz and speaker 'b' is flat to 60hz.

If I electronically crossover both speakers at 80 hz, negating the need for speakers' to produce those low power draining frequencies, and give both speaker the same power within the same range, will speaker a produce sound at a great efficiency.

Poorly stated, but do you get what I mean?

[Magnetar]

They will have the same efficiency if they are both flat at 80 cycles and have the same radiation pattern.

[mitchyz250f]

I forgot to mention this would be with an electronic crossover, my bad.

Let me ask the question another way. Both speakers are given one watt of power during testing to determine efficiency. If speaker a is no longer using all of the one watt to produce power/sound below 80 Hz isn’t that power available to produce sound above 80 Hz.

[kelticwizard]

No.

In enclosures which the speaker is mounted open to the room-such as the closed box, ported box or transmission line-the bass frequency the speaker is cut off at does not affect the efficiency at, say, 400 Hz.

In bandpass boxes where the woofer is mounted on a partition between two chambers-vented in front, closed or vented in back-then the efficiency of the speaker/enclosure combo can be raised if you design the enclosure to give a higher bass cutoff. But of course, those enclosures only handle bass frequencies anyway.

But in closed box, ported box, or transmission lines, the midband efficiency is the midband efficiency, regardless of the bass cutoff.

[mitchyz250f]

I think I have been stating the question incorrectly. The speaker’s efficiency does NOT change. However, since that one watt is no longer being spread out over such a large range, are you effectively increasing the wattage available at the other (higher) frequencies?

[AndrewT]

Originally posted by mitchyz250f
I think I have been stating the question incorrectly. The speaker’s efficiency does NOT change. However, since that one watt is no longer being spread out over such a large range, are you effectively increasing the wattage available at the other (higher) frequencies?

no.
The efficiency as stated right at the beginning is the same for both speakers.

[ocool_15]

Originally posted by mitchyz250f
I think I have been stating the question incorrectly. The speaker’s efficiency does NOT change. However, since that one watt is no longer being spread out over such a large range, are you effectively increasing the wattage available at the other (higher) frequencies?

If the signal is being filtered before the input of the amp at 80 hz the amp is no longer required to produce below 80 hz at the same level. How much will depend on the filters slope and Q. You will end up with more power available above 80hz. It will also depend on the source/music.

[mitchyz250f]

Thanks

[phase_accurate]

Not only will the amp's headroom increase. The speaker's will rise as well if they have to handle less power at the lower end.

Rergards

Charles

[mitchyz250f]

Is there calculation for this. I think it takes 4 times more power to make a 50 Hz tone than it does to make a 100 Hz tone at the same level. Did I increase my headroom X db? Just throwing numbers out there to help clearify the question,