Fundamental speaker, receiver, and sound question

[christ1]

I am relatively new to advanced home theater audio, or I have never really bought speakers with any thought to the room they were going in.

So I have a basic question-can a speaker and receiver combination be chosen such that they are too big for the room? If I hook up say a RF-7 as the left and a RF-42 as the right speaker to my receiver, will the volumes be approximately the same from both speakers? Or will the more powerful RF-7 be louder? I would think they would have the same volume because the receiver would be outputting the same power to both speakers-the receiver does not know what the characteristics are of the speaker that it is hooked up to. And that would mean the main difference between any 75W and 250W speaker is the latter can get much louder (when in the same room) because the power is proportional to the volume (obviously there could be other quality differences too). Thus does each speaker have a power range that it sounds best when within? If the room is too small the volume dial would be turned down (thus lowering the power to the speaker) to be at a comfortable sound level, but then you might not be in an optimum range. My guess is the dB as a function of frequency curve changes as the power to the speaker changes, so that turning down the receiver volume may result in the lower frequencies not being heard, for example.

Is any of this true? Do you get to the point when a more powerful speaker and receiver combination for your particular room is just a waste of money because at normal listening levels the cheaper (less powerful) speaker and receiver could easily handle the task and might be a detriment if certain frequencies cannot be heard if the receiver volume is turned too low. As an added complication, I believe I read that if the receiver volume is lowered too much the receiver will stop sending certain frequencies to the speakers altogether.

I have not mentioned anything about distortion but I have a hunch that is a large part of the answer.

Hopefully it at least makes sense what i am trying to get at. Thanks.

[willland]

If I hook up say a RF-7 as the left and a RF-42 as the right speaker to my receiver, will the volumes be approximately the same from both speakers?

RF-7II = 101dB @ 2.83V / 1m

RF-42II = 95dB @ 2.83V / 1m

If your receiver pumped 1 watt(2.83v) at an 8 ohm load into each speaker and you were sitting at a distance of 1 meter, the RF-7II's would be 6dB's louder. So no the volumes would not be the same.

Bill

[WMcD]

I am relatively new to advanced home theater audio, or I have never really bought speakers with any thought to the room they were going in.

So I have a basic question-can a speaker and receiver combination be chosen such that they are too big for the room?

No, not within reason. Not in the circumstances which you discuss.

If I hook up say a RF-7 as the left and a RF-42 as the right speaker to my receiver, will the volumes be approximately the same from both speakers?

Two different models can have different efficiencies, as mentioned by others.

Or will the more powerful RF-7 be louder? I would think they would have the same volume because the receiver would be outputting the same power to both speakers-the receiver does not know what the characteristics are of the speaker that it is hooked up to. And that would mean the main difference between any 75W and 250W speaker is the latter can get much louder (when in the same room) because the power is proportional to the volume (obviously there could be other quality differences too).

You are putting a few different concepts together here. With the same input (gross generalization) the more efficient speaker will have a greater acoustic output.

The power ratings of speakers is a difficult subject. Essentially we are looking at max power input with average music before something burns out.

But you have to look at acoustic output. A speaker which has low efficency might need to tolerate high power input but have less acoustic output.

Thus does each speaker have a power range that it sounds best when within?

Generally, no. The problem is usually that higher levels cause distortion problems. Horn are efficient and thus have less distortion at high levels than direct radiators. The otherwise distortion masks the low level signals in the music. People pretty much uniformly report that they are able to hear the low level music sounds when the overall music level is high.

If the room is too small the volume dial would be turned down (thus lowering the power to the speaker) to be at a comfortable sound level, but then you might not be in an optimum range. My guess is the dB as a function of frequency curve changes as the power to the speaker changes, so that turning down the receiver volume may result in the lower frequencies not being heard, for example.

This depends on a few things. Generally the freq response does not change much, but there is a dynamic range issue. If you have a speaker which is prone to distortion at high levels, turning down the volume will clean things up.

The other issus is the Fletcher Mullen (sp) equal loudness curve -- which has nothing to do with the speaker. Our ears are are doing what you describe. Ears have a relatively flat reponse at 100 dB. But down around 30 db (a quiet room) we only hear a band around 3500 Hz. For example, in a quiet night, you only hear crickets cherping. Other sounds are there but we can't hear them.

The loudness boost switch on amps goose up bass and sometimes treble to solve this problem.

Is any of this true? Do you get to the point when a more powerful speaker and receiver combination for your particular room is just a waste of money because at normal listening levels the cheaper (less powerful) speaker and receiver could easily handle the task

True in a way. But it is not particularly a room thing. Room response is a big topic but I have never seen anthing to indicate that room size introduces any roll-offs because of level, alone. It is true that rooms can boost freqs which you might need or want.

and might be a detriment if certain frequencies cannot be heard if the receiver volume is turned too low. As an added complication, I believe I read that if the receiver volume is lowered too much the receiver will stop sending certain frequencies to the speakers altogether.

No, not so. The volume control decreased all freqs. The only exception to this is when there is some sort of "auto-loud" function which attempts to match the F-M curve. You see this on some AV receivers for a "night" setting. I have not heard this. But basically. All low level signals are boosted and bass and treble are boosted.

There is a similar issue in "The Loudness War" of mixing pop music and radio transmission. It is possible to goose all levels to a narrow band of dynamics.

I have not mentioned anything about distortion but I have a hunch that is a large part of the answer.

Well, it is. I don't think it is much of an issue between the two speakers you discuss. But if you go up to K-Horns, (and to a lesser extent smaller Klipsch bass horns) there is a great deal of magic which I've never heard duplicated.

For the record: It seems to me that speakers with very good low freq extension somehow don't need as much F-M equalization.

Hopefully it at least makes sense what i am trying to get at. Thanks.

WMcD