is my amp good enough? STR-DA9000ES

[craigsub]

Here are 2 speaker graphs which show the in room response of our basement theater. This is with no smoothing nor gating:

Graph 1:



Graph 2:

[Lanceb1b]

What speakers were used? Does it matter what speakers were used, or are you just showing us FR of your room? What treatments are you implementing?

What color is the carpet:poke:

[craigsub]

The room is pretty neutral. This is a response curve with no eq or auto-eq used, either.

The question is ... can anyone see a difference between the response curves of these 2 speakers ?

[Lanceb1b]

The room is pretty neutral. This is a response curve with no eq or auto-eq used, either.

The question is ... can anyone see a difference between the response curves of these 2 speakers ?

Well I used GIMP to overlay the 2 and here is my result..

[Mep]

Guessing one is some well know expensive speaker and the other is the WAF-1? At +/- 10 db it seems the room accoustics are the main factor and not the speaker, which isn't surprising.

[blackzarg]

I could only tell the slightest difference between the 3k and 4k frequencies. Lance's graph confirms my eyes! :goodvibes:

Hehe, hope Mep is right with that guess!

[Lanceb1b]

I would like to see down to about 80 or 100hz...

[craigsub]

Guessing one is some well know expensive speaker and the other is the WAF-1? At +/- 10 db it seems the room accoustics are the main factor and not the speaker, which isn't surprising.

The peak is at 87 dB, and the valley is at 77 dB ... which is +/- 5 dB.

And no, this is not the WAF-1.

It is the same speaker, tested twice.

In the Purple graph, it is a pair of speakers being tested for a response curve at the listening position.

In the green graph, it is the same speakers being tested through a speaker switcher, attenuating the speakers by 4 dB using the switcher, but adding 4 dB using the pre-amp, to achieve the same actual SPL.

The purpose of the test was to find out what effect the switcher had on the response curve of the speakers.

[droht]

Sounds like someone is getting ready for a speaker shootout and is trying to resolve any questions about procedure up front...

WAF-1s vs ???

What do you still have lying around from bookshelf shootout?

[etcarroll]

What speakers were used? Does it matter what speakers were used, or are you just showing us FR of your room? What treatments are you implementing?

What color is the carpet:poke:

Does the carpet match the drapes? :no clue:

[Ajax]

What do you still have lying around from bookshelf shootout?

I believe you and I are thinking along the same line. :yes:

[dane]

In the green graph, it is the same speakers being tested through a speaker switcher, attenuating the speakers by 4 dB using the switcher, but adding 4 dB using the pre-amp, to achieve the same actual SPL.

The purpose of the test was to find out what effect the switcher had on the response curve of the speakers.

But that is only measuring dbSPL ... Could the switcher still be imposing phase changes that the SPL measurement would miss?

Are you measuring both speakers or just one?

Could you route one speaker through the "positive" direction of the switch and the second through the reverse direction (from output to selected input)? If there were any altering of the signal other than attenuation it might reveal it better that way.

Alternatively I wonder if putting through the selector switch out of phase and then wiring them back proper-phase from the box to the speakers might help reveal any other anomalies?

I'm not a speaker selector box junkie, so these are all hypothetical questions that I have ... but would also love to know the answer to for OUR next GTG ... :D

thanks!
..dane

[craigsub]

But that is only measuring dbSPL ... Could the switcher still be imposing phase changes that the SPL measurement would miss?

Are you measuring both speakers or just one?

Could you route one speaker through the "positive" direction of the switch and the second through the reverse direction (from output to selected input)? If there were any altering of the signal other than attenuation it might reveal it better that way.

Alternatively I wonder if putting through the selector switch out of phase and then wiring them back proper-phase from the box to the speakers might help reveal any other anomalies?

I'm not a speaker selector box junkie, so these are all hypothetical questions that I have ... but would also love to know the answer to for OUR next GTG ... :D

thanks!
..dane

Dane, I no longer have this switcher here, so most of your questions are moot. However, I suggest you re-read what I posted earlier. You might find some answers already there ... :angel:

[Mep]

Looks like a successful test then and really proves the point.

[dane]

Dane, I no longer have this switcher here, so most of your questions are moot. However, I suggest you re-read what I posted earlier. You might find some answers already there ... :angel:

Alright, overlooked that you said it was a pair of speakers.. :angel:

My other questions I think are still valid -- which can be boiled down to this question, "what type of qualitative information can a dbSPL graph not provide about a system?" or put differently, "what changes to a system can occur that cannot be captured by a dbSPL graph?"

I'm not causing trouble, just always wondered the answer to that question. Certainly when trying to integrate subwoofers into a system phase response issues can manifest themselves as peaks and valleys in a dbSPL graph... But I also suspect that that dbSPL graphs don't do much to provide how detailed a speaker presentation can be at presenting individual frequencies without smearing them together.. so I THINK my question is still valid? :no clue:

..dane