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La Scala AL5 What a Painful Experience


GlennyC
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So, before I throw my AL5s under the bus, I am experimenting with angling the speakers more or less towards the listener/SPL Meter. As the frequencies get higher they become more directional. I want to make sure I am forming a good triangle between the angle of the speakers and the listener's head (or SPL Meter). More more measurements/testing to follow. 

 

PS: Thank you Chris A for your help.

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I recommend posting measurements with the microphone taken from 1 meter or less in front of the loudspeaker with the microphone centered on the loudspeaker top-to-bottom...one loudspeaker at a time.  Additionally, I recommend posting full sweep measurements, not just HF measurements, and the vertical scale resolution at no more more than 5 dB/vertical division, and smoothing at 1/6th octave or greater (i.e., 1/12th, 1/24th, etc.). 

 

Otherwise, there isn't much that a reader here can do to interpret what you've actually got.

 

Chris

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Ok, so I measured each speaker independently with a Behringer microphone 1 meter from the center of the high frequency portion of the La Scala AL5 pair.

 

BLUE LINE - Left channel (speaker) of my AL5 pair.

GREEN LINE - Right channel (speaker) of my AL5 pair.

PURPLE LINE - Switched in my Heresy III for the Right speaker of my AL5 pair - all else stayed the same just the wires at the back of the speaker were moved from the AL5 to the Heresy III - then re-ran the right channel test.

 

Looks like the crossover or the tweeter is bad on my Right speaker of my AL5 pair!!!

Left AL5 OK Right AL5 BAD Right Heresy OK.jpg

Edited by GlennyC
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31 minutes ago, GlennyC said:

Looks like the crossover or the tweeter is bad on my Right channel (speaker) of my AL5 pair!!!

 

These guys are like, miles above me....but could it be as simple as a loose wire either on the driver or in the crossover?

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1 minute ago, Coytee said:

 

These guys are like, miles above me....but could it be as simple as a loose wire either on the driver or in the crossover?

Yes... it could have loosened in shipping. But it is internal to the high frequency box of that speaker. The midrange in that box is working. Not the tweeter though.

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I'll start with the dealer Crutchfield tech support tomorrow when they open. They may give me the tech support number at Klipsch. If it is as simple at removing the back panel of the high frequency box and then jiggling a wire, I'm down to do that. Better that than sending the high frequency box back to Klipsch.

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26 minutes ago, GlennyC said:

Better that than sending the high frequency box back to Klipsch.

 

Only way I'd do that is if it was one way.....  There's no way I'd trust the shipping companies to not damage it somehow or another.

 

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LaScalaNoEQ.jpg

 

This is a lot more unbalanced than I've seen any other La Scalas in-room--and I'm not really talking about response above 4 kHz.

 

Could you post a picture of them in-room and describe where you had the microphone relative to the loudspeaker when this measurement was taken? 

 

Chris

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I had the AL5s about 10 feet (12 feet center to center) apart and the microphone was 12 feet back from the center point between the two speakers. I also had my subwoofer on. It kicks in below 55 Hz. And the AL5s were not angled to point the higher frequency drivers at the microphone. The speakers were straight not angled (pointed perpendicular to the line between them). So I was doing a lot of things wrong. I will remeasure with the subwoofer off and speakers angled at the microphone. 

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...and at 1 metre (instead of 3 metres), with the microphone directly in front, centered on the front baffle? 

 

All you're doing measuring so far away from the loudspeaker is picking up all the non-minimum phase room modes and early reflections.  Those room factors need to be minimized during the measurement.  Those early reflections and room modes are the reason why "room correction software" has so much trouble getting it right in-room, because the makers of those software packages tell the user to put the microphone much too far away from the loudspeakers when the software is trying to EQ the full spectrum of each loudspeaker.

 

Chris

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5 minutes ago, Chris A said:

Nevermind...

Does that mean I'm a hopeless case? I do have to thank you Chris A for pushing me to measure each AL5 separately. That's the only way I would have found the tweeter problem in my right speaker.

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Never measure more than one loudspeaker at a time...because all you get is garbage in terms of measurement results.

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I am afraid the suggestions are being lost.

 

Measurement should be close (1 meter or less). This is what the speakers is putting out (mostly). First thing is to get that right. Once accomplished then maybe you want to measure at the listener's position (I said maybe). If you measure there, then you are getting  the output of the speaker interacting with the room. Do you make adjustments above this frequency region (that is a loaded question)?

 

There is a spectral region where you might want to make adjustments (relatively low frequencies) and there is a spectral region region where you do not want to make adjustments (relatively higher frequencies &  you should leave it alone). Where is this dividing line (low vs high)? The answer is more complicated but it is typically  around 300 to 500 Hz and I am being deliberately vague. Check in Toole's book and he will give you a better understanding.

 

IOW, correct "room issues" at the low frequencies but not the highs.

 

Good luck,

-Tom

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