Speaker upgrade, how significant?

Here the Forte III which would be considered ugluy if your amp is an ACA.

Ouch! No matter how flat that speaker is on axis, the impedance curve is in part a reflection of the total power response, which in turn is related to how a speaker will sound in a room (as opposed to an anechoic chamber).

I can hear ugliness just looking at the impedance curve, and it comes with an equally ugly time domain performance and spectral decay.

719KF3-fig7.jpg


719KF3-fig8.jpg
 
The Forte III uses midrange and treble compression drivers. The impedance plot follows what you'd expect. The same is true for the impulse response given the path differences between the associated drivers on their respective horns. Neither of those metrics, however, would indicate a speaker that's going to sound bad unless you were going to connect them to an amplifier with high output impedance.

What does give major cause for concern is the wonky frequency response and uneven off-axis response. In this regard the 600M is miles better. Then again if these are paired with an amplifier with high output impedance all bets are off as to what the frequency response looks like now.
 
Neither of those metrics, however, would indicate a speaker that's going to sound bad ...
That's one of the most surprising ideas that I have heard, at least in the context of a a loudspeakers ability to reproduce the electrical signal inputted into a reasonable facsimile of the original recording, in five decades of working professionally in sound reproduction. Of course if a listener doesn't desire or expect a loudspeaker to reproduce sound that approximates the recorded source inputed into its terminals, then all bets are off. :)
 
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Johnmath - are you sure that your read the 5th element correctly? Although I understand your point, I think you missed part of the post just above yours.

But then, I've only been in pro audio for 4.5 decades, so maybe I'm also missing something. :D
 
frugal-phile™
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I accepted it as a speculation.

Based on solid prior evidence. Go look at the FR of any amplifier with highist Rout on the simulated complex load one can get a very good idea how big the effect is.

Everharmincs has always seemed to lean on measurements… here that we have (mosty) measurements guiding the answer, he wants a listening test. Guess one can never be right?

Here the FR of an amp with similar Rout to the stereo ACA.

119ATM300fig01.jpg


dave
 
Everharmincs has always seemed to lean on measurements… here that we have (mosty) measurements guiding the answer, he wants a listening test. Guess one can never be right?
Only in your own perception, which happens to misguided. I've always advocated listening to speakers when making purchasing decision.

After all these years, still no example of lots of audible sound that can't be measured?
 
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Showing the Forte III example with a selection of Zo. Red with 0.25 ohms, in a system without defects this magnitude of variations might be audible.. Blue with 3 ohms, attainable and less likely not to be heard.

What is it exactly that we're supposed to be showing?
 

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Thank you again everyone. I really appreciate all the information provided.

I live in an area that’s several hours from any variety of audio gear so it would be very difficult to test anything similar to what I have now, and I have a pretty strong attachment to my current diy components. I picked the forte IVs based only on reviews of the sound and for some reason they give me a real nostalgic feeling when I see them.
 
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I realize this is a difficult and crazy question.

My only system is an ACA 1.8, Bottlehead Moreplay preamp, iPhone and Klipsch RP 600M speakers. I built the amp and preamp because I wanted a fun project and I found out I really like the way they sound, even if it’s just with my iPhone. I got the speakers because of online reviews and the recent sale klipsch had.

All else remaining equal, would swapping in a pair of Klipsch Forte IVs make a substantial difference? Is this a Chevy volt to a Corvette, or a Honda Civic to a slightly more optioned Honda Civic? All analogies welcome.
Better speakers also sound better, so you will have a change. But there's one thing that might not make a good sound, and that's bad acoustics.