My new ideas to have quality sound effect.

[space2000]

Hi all,

Thank you for your comments in past. I had made few amps and realized that there is no solution using only one amp to have purely three dimensional sound effect. I just came out with my own new ideas. I like class-A mid and treble sound very much but the problem is bass. I had decided why not use two amps to get nice and quality sound effect.

I have posted my ideas pic. I want to use two amp.

Mid and treble = Class A 50w
For BASS = class D 150w.

Hope for more ideas and discussion from you all.

Best regards
Michael

[Greg Erskine]

hi space2000,

Ideally, the "crossovers" should be replaced by active filters before the amps.

See ESP:

http://sound.westhost.com/bi-amp.htm

regards

[AndrewT]

I disagree with ESP (and most other authors/builders) on the power requirements of the various frequency band drivers.

I contend that using drivers of the same sensitivity require the same voltage supplied to the driver, irrespective of the frequency range.

If the treble, mid and bass drivers are all 8ohm, 90dB/W/m, then they all need 40Vpk to reproduce a transient peak of 110dB @ 1m.

When one mixes drivers of different sensitivity and/or impedance, only then should an adjustment be made to the supplied signal voltage to each driver.

[paulb]

I think the ESP article only refers to the spectral content of typical music, not sensitivity or gain requirements. They all need the same gain but tweeters will require less power because less of the music power is in their range.

[AndrewT]

Originally posted by paulb
but tweeters will require less power because less of the music power is in their range.

that's precisely where we disagree.

The transient peak voltage requirement must still be met.

[Nordic]

Thanks for answering so many of my questions...
Yep Andrew that makes sense... if gain determines that output should be xV and it is connected to Yohms it is going to require Zamps...regardless of the frequency

[sreten]

Originally posted by AndrewT

I disagree with ESP (and most other authors/builders) on the power requirements of the various frequency band drivers.

I contend that using drivers of the same sensitivity require the same voltage supplied to the driver, irrespective of the frequency range.

If the treble, mid and bass drivers are all 8ohm, 90dB/W/m, then they all need 40Vpk to reproduce a transient peak of 110dB @ 1m.

When one mixes drivers of different sensitivity and/or impedance, only then should an adjustment be made to the supplied signal voltage to each driver.

Hi,

Well the implication you are making is transient peaks in music can
occur anywhere in the frequency range, which is true is terms of CD
red book standards, but ignores typical high quality music spectra.

The latter is the more pragmatic approach. The former is rigourous
but over-engineering. I am not suggesting amplifiers should be
chosen on average spectral power either, the difference between
say bass / mid and treble amplifiers should be less than this implies.

The argument regarding voltage is a non argument. It applies whether
the c/o point is 100Hz, 1Khz or 10Khz, i.e. it misses the point completely.
100W for below / 100w for above 10Khz is obviously nonsense.

/sreten.

[AndrewT]

Originally posted by sreten
100W for below / 100w for above 10Khz is obviously nonsense.

I don't agree on nonsense.
I believe the transient peaks are very similar when looking/listening at/to a whole range of music.

That's where discos fall down. The treble SPL levels are way down on the rest of the frequency range. This leads to gross overloading of the treble and removes all semblance of realism, particularly on female vocals and similar HF content.

[Andre Visser]

Originally posted by sreten
The argument regarding voltage is a non argument. It applies whether
the c/o point is 100Hz, 1Khz or 10Khz, i.e. it misses the point completely.
100W for below / 100w for above 10Khz is obviously nonsense.
/sreten.

I agree with AndrewT, the output voltage of the amps should be the same. You can get the same amplitude HF and LF in music.

[sreten]

Hi,

Well you are both missing the point completely, some engineers .......

Your saying two 100W amplifiers can be used split at 100Hz,
1kHz or 10kHz and it makes no difference, it is "technically correct"
because of voltage capability, you cannot see the wood for the trees.
At 10kHz it only makes sense for white noise and fried tweeters.

FWIW :

Take 100w / 400w amplifiers , the 400w has x2 voltage capability.

Take 4 x 100w amplifiers optimally split, you can argue about this but
lets use pink noise, so they all need ~ the same width in octaves.
Say 115Hz, 640Hz, 3.5khz c/o points.
(edit :
do you seriously think 4 x 100w is correct for 5khz, 10kHz, 15kHz ?)

What theoretically is the maximum equivalent voltage swing of these
4 amplifiers into a 4-way speaker, ie. what single amplifier offers
the same maximum voltage capability in each band simultaneously ?

The answer is 1.6kW ....... even though max average = 4 x 100W,
(edit) wideband and only 100w continuous sine wave power.

So should the input to the 4-way active crossover be limited to be
the equivalent voltage capability of each amplifier ? of course not,
unless the only input allowed is a sine wave, where it makes sense.

/sreten.