boomer wrote:
On 1/9/2014 2:37 PM, Ian Jackson wrote:
In message , boomer
writes


We aren't talking multiple arrays in large places. Of course multiple
speakers will provide more gain than one speaker. And horn
speakers get
their "gain" by directing more energy in one direction; there is a
loss
of signal in other directions. It has nothing to do with "impedance
matching to the air" (there is no such thing).

The laws of physics say it is impossible to create energy out of
nothing,
which is what you would be doing if you quadrupled the power (6db
gain)
by placing two speakers in phase. If you "measured" this, you need a
new meter.

I would love to tear apart your "reference".

Non believer in facts. If you don't believe you should do tests,
like me.

I'll skip the horn for now..

If you can't believe two speakers will move TWICE the air doubling
intensity, I don't know what else to say, except test yourself.

Greg


I have (I was an EE major). You can't create energy from nothing. The
laws of physics don't allow it. And I currently have a business which
deals with home entertainment systems.

At MOST, two speakers in phase can move twice the air. No more, and in
reality, because of inefficiencies, it will be less.

I hate to question the law of conservation of energy at all, but I
must say that there could be more energy delivered from two 8 ohm
speakers in parallel than a single speaker powered by the same
amplifier. Many amplifiers have 4 ohm outputs. So, you see the
possibility. You would be delivering the same energy to both speakers
as was delivered to one.

Of course for those who believe in magical energy production, no
reasoning will help.

I personally have a Crown 810 powering a couple of AR SRT380s. The
amplifier has 4 ohm outputs and the speakers are 4 ohms. There is
nothing to be done to increase sound power except buy more efficient
folded horn types. I have neither the space nor money to do so.
However, at 420 watts rms per channel as it is now, I really don't
require more power. Jimmy Hendrix sounds just fine to me. :-)

So, matching output impedance of amplifier to speaker will result in
maximum energy transfer and using the most efficient speakers will
result in of course more acoustic energy produced. All we are talking
about here is not wasting energy in poor efficiency systems.

If I understand things correctly, I don't think that many audio
amplifiers have an output impedance as high as 4 ohms. It's generally a
fraction of an ohm. However, an amplifier will be designed to deliver a
given power into a given load with a specified maximum distortion.

That too is my understanding. I believe that connecting a 4 or 2 ohm
speaker to an amplifier rated at 8 ohms would likely cause distortion.
For those still following this thread here is a simple explanation of inertial dampening.
http://www.crownaudio.com/media/pdf/...ing_factor.pdf

The output impedance of the Crown 810 is rated at less than 10 milliohms.
This is an important specification when you are wanting to hear very
little distortion. There of course other important factors including
Frequency Response, Phase Response, Signal-to-Noise Ratio, Total Harmonic
Distortion (THD), Intermodulation Distortion (IMD), Damping Factor, Slew
Rate, Output Power, and Crosstalk. And of course then there is the whole
science of speakers. Amplifier design is much easier to understand. I
cannot really get my head around all the factors that come into play
designing speakers. It is complicated enough to almost appear to be magic to me.

You would get more distortion with lower z, but it would be mostly depend
on the volume level. Kept low, distortion would be minimal.

Here is another post about damping. It even includes getting gain from two
drivers.
It's old, been there, done that.....

http://zekfrivolous.com/sub/usenet/pierce/damp.txt

Greg