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KPT-942-4 Xilica tips


CJ Wolff

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Hello,

 

I have the 942 b(4) connected to a monolith 7x200 fed by a bluesound node2i.  I swapped out some passive crossovers with the xilica.

 

I have the L and R from the node2i coming into input 1 and 2.  The channel 1 output goes to the right 402 horn, the channel 2 out goes to the left 402 horn, the channel 3 out goes to the right bass box and 4 out goes to the left bass box.

 

I've noticed that the bass from the right bass box is nearly non existant while the left bass box will drive you out of the house.  I know I'm missing something here.

 

I"m attaching my high pass and low pass xilica settings for any help you can provide.  Thank you.  Please help. :)

 

Christopher

 

 

LPsetting012601.png

HPsetting012601.png

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8 minutes ago, Dave A said:

Chris, Post all four channels here. Need to see what is different. Chris is the resident Xilica guru. Do your neighbors love you yet?

@Dave A this has been a fantastic project.  I'm 95% of the way there.  I'm so glad to hear from you.  I don't have any neighbors on the adjoining lots but my wife is loving me, that's for sure.  

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1 minute ago, babadono said:

Bypass is enabled on PEQ filters 5,6,7,and 8 on left channel. Level is 0dB so should not make any difference....but

Ok I added bypass tonight for grins.  Left channel is great.  Right channel has the bass problems.  I’ll back out the bypass.  Thanks for bringing it up.  

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7 hours ago, CJ Wolff said:

...I've noticed that the bass from the right bass box is nearly non existent while the left bass box will drive you out of the house.  I know I'm missing something here...I"m attaching my high pass and low pass Xilica settings for any help you can provide.  Thank you.  Please help. :)

 

Christopher

I've found that one of the reasons why we have independently adjustable channels with DSP crossovers is due almost entirely to the "sparse room mode" low frequencies, generally below 200 Hz that gives us so much variation in SPL response from loudspeaker locations and listening positions in-room, and time alignment issues between drivers/horns within a loudspeaker itself.  Higher frequency settings between loudspeakers tend to be less variable, in my experience. 

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If you look at the Klipsch Cinema settings, they assume some sort of positioning in the front, top or sides of the theater as a starting point for actually dialing in the loudspeakers for some sort of happy medium to cover as many theater seats with as flat an SPL response as possible.  Whether or not there is a screen that the loudspeaker is shooting through, and the brand and type of screen itself--these are also variables that probably encourage the theater owners to have everything dialed in using measurements from more than one audience location.  This is probably a larger part of the reason why these "suggested cinema settings" don't work for home hi-fi duty.

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For home hi-fi, however, the needs are also fundamentally different.  The room reflection time delays are usually dramatically shorter than commercial cinema, and the reverberation times in home hi-fi rooms never really get down to the -60 dB level that larger venues use as their reference.  I've also found that nearfield listening in home hi-fi places specific demands on the other half of the transfer function response: loudspeaker phase response, especially at low frequencies. 

 

To understand the differences in home hi-fi rooms of the low frequency response of the different loudspeakers, we also need to know two more things:

 

1) the position of the loudspeakers (say its the left, center, right loudspeakers, etc. in a multichannel array) to the room boundaries--walls, ceiling and floor, usually in that order of importance. Symmetry of loudspeaker and listening position placements and distances to walls is usually assumed but rarely found in actual practice in home hi-fi.  A picture of at least the front of the room with your loudspeakers is usually the best way to respond.

 

2) individual REW measurements of the loudspeakers in the home hi-fi array (I'm now assuming stereo only for your setup).  Considerable variation in low frequency response is still found in even very symmetrical setups.  These show us many things to answer your question--"why is there still variability in low frequency response?"

 

If you want a reliable answer to your question, these two sources of information must be known to those trying to provide an answer.  If only one of the two is possible, it must be the full REW measurement files of each loudspeaker separately using one metre microphone distance from the front of each loudspeaker location, on-axis, because much of the position of the loudspeakers is revealed from REW measurements.  You can send me a PM to me for my email address so I can help you in this way.

 

Chris A

 

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That K-402 centerline is a little high for your flat screen TV.  Have you thought about rotating the bass bins 90 degrees sideways and setting the K-402s on top of them?  That would place the K-402 centerlines almost at the same height as the flat screen, and would get the K-402s closer to the centerline of the woofers--thus reducing the polar lobing between the bass bin and the K-402s at the crossover frequency).

 

Here's a vertical polar map of the KPT-942/4 with the K-402s on the bass bins in your present orientation:

 

1597218319_KPT-942-4VerticalPolarMap.GIF.792f437276e96224e8be93109dc962d8.GIF

 

Notice the jog to the left between ~500-250 Hz.  That's the polar lobing that I was referring to.  Moving the K-402s closer to the centerline between all four woofers reduces this effect.

 

It's just a thought...

 

Chris

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I would suggest based on what I’ve read so far that you verify that the (4) woofers in the LF giving issues are wired properly and all working in polarity.

 

I suggest you remove the amplifier speaker wire and then using a 1.5v to 9v battery to apply voltage to the speaker input terminals verify that all (4) woofers are moving in the same direction.  (Battery +) to (Speaker +) and (Battery -) to (Speaker -) should move all the cones outward and if not then check all wiring for proper polarity connection to the drivers.

 

I also suggest if you have a meter that you read the resistance at the speakers input terminal and verify it reads the same as the speaker that sounds like it is operating correctly. If for any reason the drivers aren’t wired correctly in series/parallel you will see that in the meter reading and again warrants checking the wiring for proper series/parallel connections for the system.

 

miketn

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First of all I need to reach out and show my gratitude to @Chris A @Chief bonehead @Dave A @richieb@mikebse2a3@babadono for helping me step through this.

 

It turns out that there was a polarity mismatch.  Two of the four woofers were pushing and the other two were sucking. 

 

60 seconds with a screwdriver fixed the problem.  Now I have LF response again.  lol

 

Next question which I will save for another thread is GAIN. 

 

 

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