Center channel Impedance.

[E-Stat]

Although amp will not have trouble driving the load, but by connecting speakers in series, it does change the electronic characteristic of speakers.

Isn't that essentially what I said in the two sentences you quoted?

I tried two speakers in series, and notice that not only it pretty much kill speakers bass responce, it made them sound lifeless.

For starters, bass response for the voice track really isn't that critical. You might be surprised how many speakers use series wired components. Aren't you one of the Roger Russell disciples? You do realize that his IDS speaker is wired thusly, right?

rw

[Smokey]

You might be surprised how many speakers use series wired components. Aren't you one of the Roger Russell disciples? You do realize that his IDS speaker is wired thusly, right?

Don't know who Roger Russel is

If speaker have series wired components, then its specification is designed to have 20 volt rail cross whole combined resisitance to have optimum sound. That would be different from combining two speakers that have optimum sound that was designed to have 20 volts cross each speakers.

As a corollary of what you have said, does that imply that by running speakers in parallel at 4 ohms , the speakers should sound even better? I'm not being facetious, I really don't know. If I were to guess, I would think that, in parallel, there would be 20 volts across both speakers and the amp would just double the current output with no change in sound, except for the 3 db increase by having two speakers instead of one.

That would be true if amp can handle excessive double current. But most amp can't which mean with excessive current also come excessive distortion. I rather have one speaker with less distortion than two with added distortion. There is old saying in electronic that "there is no free lunch". Which you have to give up something (distortion) to gain something else (volume).

As an example... P = 20 volts squared/5 ohms = 80 watts for a single speaker, but in series... P = (20/3)squared / 5 ohms = 8 watts per speaker. Does that sound correct?

Now considering my speakers... They are rated down to 100 Hz at which point I assume the impedance increases, so power is not wasted below that point. I have the speakers set to small and the crossover set to 200 on them so that I have 8 watts of electrical power available to drive each speaker from 200Hz to 16kHz. Besides that, by running three speakers, each additional speaker adds a 3db increase in acoustic power for a 6db increase.

The formula is correct, but I am not sure adding more speakrs that have the same volume neccesary equal to added 3 db acoustice power since the loudness have not changed. I could be wrong here though so may be somebody else can chime in on this.

In total, I have 8 watts of electrical power available but the 6db acoustic output gained by using 2 additional speakers gives me the equivalent acoustic power of 32 watts. In other words, I would get the same output running one speaker at a maximum of 32 watts. Does this make sense?

I don't think that is correct. Since each speaker will have the same volume, adding more speakers with same volume does not equal "linear" added acoustic. Just like having a table fan in a room with 40 db acoustic noise. By adding more table fan to room, the noise level will not increase 3 db per fan since the noise level has not change.

For example, if you add 10 more fans to room, the noise level will increase slightly, but not 3 db per fan (or the noise level in a room with 10 table fans will make you go deaf ). I hope you see the relation.

[E-Stat]

Don't know who Roger Russel is

You haven't missed anything worthwhile.

I could be wrong here though so may be somebody else can chime in on this.

You are mistaken. I get a similar +6db gain from using double New Advents. Half of the acoustic gain comes from using doubles. The other half comes from the Threshold's added power. Which is not even breathing hard driving that load.

rw

[StevenSurprenant]

That would be true if amp can handle excessive double current. But most amp can't which mean with excessive current also come excessive distortion. I rather have one speaker with less distortion than two with added distortion. There is old saying in electronic that "there is no free lunch". Which you have to give up something (distortion) to gain something else (volume).

I checked my amp specs and it supplies approximately 50% more power each time the impedance is halved which is a far cry from doubling. I realize that distortion increases with power output but as long as its below audibility, would it really matter? I only say this because at the volume I play music, I've never had too little power. At present, I use a Trends TA 10.1 digital amp on my stereo which puts out about 6 clean watts. That is more power than I need for the speakers I use and the room it's in. I built my own speakers so I'm guessing that they are about 91db efficient, at least that's what the tweeter is rated at and I don't have it padded down.

The formula is correct, but I am not sure adding more speakrs that have the same volume necessarily equal to added 3 db acoustice power since the loudness have not changed. I could be wrong here though so may be somebody else can chime in on this.

I don't think that is correct. Since each speaker will have the same volume, adding more speakers with same volume does not equal "linear" added acoustic. Just like having a table fan in a room with 40 db acoustic noise. By adding more table fan to room, the noise level will not increase 3 db per fan since the noise level has not change.

For example, if you add 10 more fans to room, the noise level will increase slightly, but not 3 db per fan (or the noise level in a room with 10 table fans will make you go deaf ). I hope you see the relation

As I said, my knowledge is limited and I went by what I've heard repeated many times, especially on the speaker building sites. BTW, When I first built my speakers, I was using two SEAS drivers per box and a Newform ribbon, but I was also bi-amping through a digital crossover and so level matching speakers elements was a none issue. However, when I went to passive crossovers, two drivers would overpower the tweeter so I reduced it to one per box which sounds about right. I suppose the point here is that two drivers compared to one really does increase acoustic output. This correlates to what I've read. I didn't measure the increase, so I don't know if the suggested 3db increase is accurate. BTW, the SEAS woofers were wired in parallel.

Again, thanks for your help.

[Smokey]

I At present, I use a Trends TA 10.1 digital amp on my stereo which puts out about 6 clean watts. That is more power than I need for the speakers I use and the room it's in. I built my own speakers so I'm guessing that they are about 91db efficient, at least that's what the tweeter is rated at and I don't have it padded down.

No matter how sensetive your speakers are, 6 watts of power is definitely not enough. Alot of poeple associate more power with more loudness which is not true because amp also have to have dynamic headroom which can go well above 100 watts.

If you don't have dynamic headroom to take of music spikes, the result would be excessive distortion better know as Total Harmonic Distortion (THD). That is why low power amps always have high THD

[E-Stat]

That is why low power amps always have high THD

Ridiculous. Low powered First Watt amplifiers most certainly do not have high THD even with zero NFB.

rw

[StevenSurprenant]

No matter how sensetive your speakers are, 6 watts of power is definitely not enough. Alot of poeple associate more power with more loudness which is not true because amp also have to have dynamic headroom which can go well above 100 watts.

If you don't have dynamic headroom to take of music spikes, the result would be excessive distortion better know as Total Harmonic Distortion (THD). That is why low power amps always have high THD

I understand what you're saying and it's true, but keep in mind that it depends on how loud a person listens. I designed my system for ultra clarity, at least that was my goal, and so I can listen at very low levels and still hear everything. Also, the system is in a very small room which also allows me to reduce the volume. I know this doesn't mean much, but I normally run my volume control at 1/4 of the max. I tried the system in a larger room and there wasn't enough power.

When I had my Quads I was pushing them with a Mark Levinson 331 which was rated at 130 watts per channel. Of course, power wasn't a problem, but personally, I think the Trends TA sounds much better. The last time I said that, the guy got mad at me and told me, in so many words, that I was out of my mind. I don't think the ML was the correct choice for my speakers, that's all. I think the Pass Labs Aleph 3 at 30 watts would have been a better choice.

I remember many years ago listening to a ML system driving Wilson Watt/Puppies and thought to myself that it was decent, but then I found another store driving the same speakers with a Pass Labs amp similar to the Aleph 3 except it put out 45 watts. The difference was astounding. Comparatively speaking, the ML system sound flat like wall paper. ML products are great, but system matching is always a must. Anyway, the sound stage with the Pass Labs was so defined that I could have walked between the performers on the stage. I remember seeing (actually hearing) the drummer placed way back in the room on the right. This was the first time (only time) that I thought that there was too much separation between instruments and performers. It was surreal. The space between the performers was as defined as the performers themselves.

I suppose that what I'm trying to say is that more power is always good, but there are some things that transcend pure power.

The soundstage I get is nowhere near what I heard at that store, but it has a certain magic. I would go for a bigger amp, but I would not trade off the sound quality. There are better amps, but at what price?

Read this...

6moons audio reviews: Trends Audio TA-10

Also

TA-10 Modifications

I've supplied a graph of the output power just in case you're interested. No need to click on the links if you're not. I would guess that the Trends amp would be similar to the Super-T on the graph.