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Robbie010

La Scala DSP Settings - Gain & Delay?

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Having now installed Fusion DSP plate amplifiers to my La Scala and dialed in a¬†basic¬†crossover, I have actual music coming from my speakers again!¬†ūüėÉ

 

Big thanks in particular to @Chris A for the patience and pointers.

 

I know there is a long way to go in terms of measuremnets and PEQ's etc, much of which is beyond my knowledeg base at the minute. However, for now, I am just looking to put the speakers back to a basic (listenable) crossover.

 

I have implemented second order low pass and high pass filters, set the crossover points at 400Hz and 4900Hz and inverted the midrange driver to deal with the 180 degree phase shift.

 

However, I am not sure what to do with the gain and delay settings?

 

In order to simply recreate the standard La Scala crossover, what gains and delays should be applied to each driver, if any?

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The delays in a "standard" La Scala crossover (i.e., with passive crossovers) will result in some fairly large time misalignments between drivers/horns.  So to hear the effect of a time-aligned La Scala, you'll need to dial in the delays to zero out those time misalignments.

 

What tweeter and midrange drivers are you using?  I've got a couple of sets of La Scala II settings, one of which that I can offer as a point of departure, but without knowing what you're actually using now, I don't believe these settings will be a lot of use to you. 

 

And when you get a chance, a REW measurement would work wonders.

 

Chris

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22 minutes ago, Chris A said:

The delays in a "standard" La Scala crossover (i.e., with passive crossovers) will result in some fairly large time misalignments between drivers/horns.  So to hear the effect of a time-aligned La Scala, you'll need to dial in the delays to zero out those time misalignments.

 

What tweeter and midrange drivers are you using?  I've got a couple of sets of La Scala II settings, one of which that I can offer as a point of departure, but without knowing what you're actually using now, I don't believe these settings will be a lot of use to you. 

 

And when you get a chance, a REW measurement would work wonders.

 

Chris


All original Klipsch drivers, K77F Tweeter (with Z brackets), K55V Squawker on K401 horns (front mounted) and K33E woofer. 

I have a friend coming round this weekend to help me with REW measurements etc. 
 

35D84ED0-99E3-4D99-88DA-DA4F74C2DB9E.thumb.jpeg.56ec5c2a390f17b7a6866d95ac534cee.jpeg

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1 hour ago, Robbie010 said:

400Hz and 4900Hz

Are you sure those are correct? Careful with that tweeter.

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Okay, I think that I made the translations correctly from Xilica XConsole to Hypex Filter Design (HFD) for the Hypex FA123 FusionAmp.  Enclosed is the exported La Scala II preset file with the following channel assignments:

 

Output channel 1 = bass bin

Output channel 2 = midrange

Output channel 3 = tweeter

 

Here is the exported presets file for that La Scala II case (1.6 mb) that you can import:  <<<<<<<<<removed--it was an incorrect file, see below>>>>>>>>>>>

 

You may have to adjust the relative channel gains since I cannot remember if all three of the amplifiers used to create the original presets had the same gain (the original was done via email for another forum member in late March of this year).  Also, I don't know if I'm interpreting the "Sum" and "Mute" colors correctly, so you'll need to check and toggle each of them if I misinterpreted what the HFD help file said.

 

Let me know if you use this, and whether or not you had to flop the polarities of "Sum" and/or "Mute", and whether or not it sounds okay.

 

Chris

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23 hours ago, Chris A said:

Okay, I think that I made the translations correctly from Xilica XConsole to Hypex Filter Design (HFD) for the Hypex FA123 FusionAmp.  Enclosed is the exported La Scala II preset file with the following channel assignments:

 

Output channel 1 = bass bin

Output channel 2 = midrange

Output channel 3 = tweeter

 

Here is the exported presets file for that La Scala II case (1.6 mb) that you can import:  La Scala II Preset for Hypex FA123.dat

 

You may have to adjust the relative channel gains since I cannot remember if all three of the amplifiers used to create the original presets had the same gain (the original was done via email for another forum member in late March of this year).  Also, I don't know if I'm interpreting the "Sum" and "Mute" colors correctly, so you'll need to check and toggle each of them if I misinterpreted what the HFD help file said.

 

Let me know if you use this, and whether or not you had to flop the polarities of "Sum" and/or "Mute", and whether or not it sounds okay.

 

Chris

 

Hi Chris,

 

Sorry to pester you but I am really struggling to open this .dat file with the hypex software, do you know how to do it?

 

I tried opening the file in REW but its the wrong format......

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On 11/19/2020 at 4:37 PM, Robbie010 said:


All original Klipsch drivers, K77F Tweeter (with Z brackets), K55V Squawker on K401 horns (front mounted) and K33E woofer. 

I have a friend coming round this weekend to help me with REW measurements etc. 
 

35D84ED0-99E3-4D99-88DA-DA4F74C2DB9E.thumb.jpeg.56ec5c2a390f17b7a6866d95ac534cee.jpeg

 

Looking good!  I like the front-mounted K-401 and the trim around the HF section.  Braces are good, too.  Your speakers should sound great once you get them dialled in.

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8 hours ago, Robbie010 said:

 

Hi Chris,

 

Sorry to pester you but I am really struggling to open this .dat file with the hypex software, do you know how to do it?

 

I tried opening the file in REW but its the wrong format......

Interesting--the export function of HFD apparently doesn't save projects to any directory, but to a certain directory.  What is more, the "export" command doesn't actually save the project, but rather some other data file, which I posted above.  Try importing the following XML file, which is apparently the actual project file:  Config.xml

I don't know what the "*.dat" file actually is -but the one I posted above is nothing but zeros (or otherwise called "zeds" across the pond) in exponential format.  Strange...

 

Let me know if the above "config" file works.

 

Chris

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15 hours ago, Chris A said:

Interesting--the export function of HFD apparently doesn't save projects to any directory, but to a certain directory.  What is more, the "export" command doesn't actually save the project, but rather some other data file, which I posted above.  Try importing the following XML file, which is apparently the actual project file:  Config.xml

I don't know what the "*.dat" file actually is -but the one I posted above is nothing but zeros (or otherwise called "zeds" across the pond) in exponential format.  Strange...

 

Let me know if the above "config" file works.

 

Chris


Hi Chris, that file has imported just fine. Thanks.
 

I’ve had a look at the filters, and you can see the delays and gains in the image below. Before I upload the filters, are these figures correct?

 

AE3C3518-A6B2-4358-9BDF-ED473D44FA77.jpeg.f6f6bcff48def9fc8a07827bab0a8069.jpeg
 

To answer your questions RE Mute and Sum, the imported settings were correct, Green is on and Red is off. However, apparently, the Sum function only works with measurements done within the¬†HFD programme, so has no effect¬†on the¬†filter graph!! ūüôĀ

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Yes, those are the correct delays and gains. 

 

I haven't used the HFD application to measure--only REW.  I'll have to read a bit further to understand that part.  What I did see (impulse response, etc.) was quite encouraging.  I'll have a chance to do it for myself in the near future, as I placed my order for two FA122s yesterday to replace my DSP and amplifiers for the Jubilees.  I'm looking forward to the dial-in and the audition of the differences.

 

Chris

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4 hours ago, Chris A said:

Yes, those are the correct delays and gains. 

 

I haven't used the HFD application to measure--only REW.  I'll have to read a bit further to understand that part.  What I did see (impulse response, etc.) was quite encouraging.  I'll have a chance to do it for myself in the near future, as I placed my order for two FA122s yesterday to replace my DSP and amplifiers for the Jubilees.  I'm looking forward to the dial-in and the audition of the differences.

 

Chris

 

The HFD programme has been very good this far, I will be spending some time over the next week or two having a real play with REW, I especially need to work out how the measurements can be gated to take out what the room is doing. That will be interesting.

 

My friend I did some work today and it was very interesting to be able to measure then tweak the filters¬†and actually see the changes to the frequency response!¬†ūüėÉ

 

If you don't mind, I have a few questions regarding the filters that you provided:

 

All of the Low Pass and High Pass filters are first order and I was told in a different conversation that second order filters are prefered for a 3 way setup, is there a reason why you opted for first order over second?

 

Again, during the conversation mentioned above, I was advised that when using second order filters there is a 180 degree phase shift that should be corrected by inverting the midrange driver. On your filter, I noted that the woofer filters have been inverted, why is that?

 

Finally, I noted that the tweeter high pass filter is set at 2500Hz and the spec sheet for the K77 says that the crossover point should be no lower than 3,500Hz. Am I best adjusting the filter in line with the spec sheet?

 

Again, many thanks for all your help with this. 

 

 

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32 minutes ago, Robbie010 said:

All of the Low Pass and High Pass filters are first order and I was told in a different conversation that second order filters are prefered for a 3 way setup, is there a reason why you opted for first order over second?

Yes, just look at your phase response plot in REW.  It will tell you all you need to know.  Also, you can see a big difference in the excess group delay plot using first order vs. second or higher order.  A flat phase response is the name of the game.  That link will tell you why.

 

32 minutes ago, Robbie010 said:

Again, during the conversation mentioned above, I was advised that when using second order filters there is a 180 degree phase shift that should be corrected by inverting the midrange driver. On your filter, I noted that the woofer filters have been inverted, why is that?

This is a more complicated subject.¬† If you are doing the delay adjustments based on REW measurements instead of "rule of thumb" delays (which I don't recommend), then you will see the effect of each order of crossover filters used.¬† In the case of the reversed polarity bass bins, it was chosen to minimize the total phase growth in the loudspeaker and to get much closer to a perfect step response (much more discussion on what I'm doing could ensue here, but I'll leave it at that).¬† The effect on your listening pleasure once the phase response in brought to within ¬Ī90 degrees of phase from ~200 Hz to 20 kHz will knock your socks off.¬† Read the linked thread that I provided just above to understand what it sounds like.

 

32 minutes ago, Robbie010 said:

Finally, I noted that the tweeter high pass filter is set at 2500Hz and the spec sheet for the K77 says that the crossover point should be no lower than 3,500Hz. Am I best adjusting the filter in line with the spec sheet?

I set the tweeter high pass filter to protect the tweeter from absorbing lower frequency signals.  It's actually the PEQs which are protecting the K-77 tweeters. 

 

You can also set the limiter (see page 34 of the Hypex Filter Design manual for the soft clip feature), which will absolutely protect your tweeters from overload voltages, i.e., it's faster than a zener diode in a passive network and without the other issues of having a zener in the circuit, and thus unlike any protection that a passive crossover could achieve.

 

Chris

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Thanks again Chris!

 

We had a play this afternoon and have tweaked some of the filters as dictated by the REW measurements! All of the graphs show a hefty 15db null at 106Hz:

 

New.thumb.jpg.5576e17f4d700b5fa3b3a563b1f3d8f1.jpg

 

Any guidance on whether this null can be corrected using the HFD software and how would be much appreciated!

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You'll have to look at the excess group delay curve at this frequency by selecting the "generate minimum phase" button under the Controls menu, and make sure that the excess group delay curve plot selection box has an "X" in it below the plot.  If the excess group delay curve is flat across and on either side of the null, then you can introduce a boosting PEQ at that point (or remove any PEQs that I've already set in that region). 

 

More likely, though, is that the excess group delay curve is highly irregular at that frequency, indicating that you've got a room mode that is the problem.  You can't do anything about those--you live with them.

 

Also try measuring the loudspeaker with the microphone at a significantly different height above the floor than it is when you took the above measurement.  If the null disappears or simply moves, then you've got a 1/4 wave to a room boundary that is the issue--not the loudspeaker's output.  Most setups will have a local null measured between 100-200 Hz due to this kind of issue. You learn to ignore them if you've identified what it actually is.

 

Chris

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On 11/22/2020 at 12:29 PM, Robbie010 said:

I’ve had a look at the filters, and you can see the delays and gains in the image below. Before I upload the filters, are these figures correct?

 

AE3C3518-A6B2-4358-9BDF-ED473D44FA77.jpeg.f6f6bcff48def9fc8a07827bab0a8069.jpeg
 

 

Hi Chris! Me again..........ūüėĄ

 

I've been having a play with the crossover you sent me and playing around with REW........ it very interesting stuff, even for a novice like me.

 

One thing I was just trying to get my head around was regarding the Delays and Gains. I am assuming these are set based upon the physical dimensions / layout of the speaker drivers and their overall response. If that is the case, can I simply apply these same settings to pretty much any crossover I may wish to design and have the correct delays and gains??

 

Thanks in advance.

 

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Unfortunately, if you change the order of the crossover filters used, the needed delays will also change.  In general, the higher the order of the filters used, the larger the required delays, and that value is 90 degrees of phase shift for every order of the crossover filters used. You can use the excess group delay measurements from REW to set the delays, or alternatively, you can use the spectrogram view.  For your DIY La Scala, I would guess the delays need to be updated from the settings that I forwarded, simply because the horns and drivers are not exactly the same.  Here's a thread on how to do that:

 

 

The gains can be set using the SPL response curve, noting that the crossover points are about 400 Hz and about 4.9 kHz.  Here's a thread that discusses how to set the PEQs, relative gains, and other stuff while changing the crossover filters:

Chris

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Help!¬†ūü§™

 

After more than an hour I have managed to produce a spectrograph that resembles @Chris A's, however, its dissimilar enough for me to have no idea how to interpret it....

 

Crossover points are 400Hz & 4900Hz

 

Have I gone wrong here? Can you please educate me on how to interpret this and what kind of delays are needed:

 

Spectrograph.thumb.jpg.120cbb685b53ddcf37a2ea85bcfcbc56.jpg

 

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If you set the vertical scale (frequency) to "log (db SPL)" instead of "linear" you will get the frequencies below 1 kHz in your plot.  Since the spectrogram plot is linear in the vertical axis, it obscures the frequencies below 1kHz to the point where I'm guessing what the delay on the tweeter and midrange channels should be.  I could guess based on what I see above, but I'd probably get it wrong (I'd guess 3.05 ms added to both the midrange and tweeter channel values to the delays that are already there, but I could be wrong).  You can see the little "dog leg" of the peak energy time curve a 3 ms on the horizontal axis, that's apparently where the bass bin is coming in relative to the midrange, but I can't tell if the frequency is 400 Hz or 200 Hz (where the peak energy time curve will begin to deviate from verticality due to the design of the bass bin itself- which is the minimum phase behavior of the horn/driver). 

 

Here is a screenshot of my settings (both from the "Controls" menu and the "Limits" menu) on top of a spectrogram view so you can replicate what I post:

 

Spectrogram limits and controls settings.JPG

 

You are also showing a great deal of nearby acoustic reflections in your spectrogram.  I'd recommend temporarily placing blankets, quilts, absorption tiles, etc. all over the top of any acoustically reflective objects (and especially the floor between the microphone and loudspeaker) and otherwise within a meter or so of the loudspeaker and microphone, just for the measurements.  This will allow you to get usable phase and group delay information in your REW measurements.  It will quiet the vertical spikes that follow the initial impulse.

 

You can increase the resolution of the smoothing (I've used 1/6th octave smoothing above, but you can use 1/12th or finer smoothing to see a more, albeit with more hash and visual distractions).  If you punch the "Controls" menu button while looking at the SPL& Phase plot, you can also punch the "Estimate IR Delay" (IR is "impulse response" here), then select "Shift IR" to zero the time in the measurement to the leading pulse of the loudspeaker, you will get much better phase plots.  Otherwise, you will get artificially shifted phase plot due to the non-zeroed "0" time point. 

 

Chris

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32 minutes ago, Chris A said:

If you set the vertical scale (frequency) to "log (db SPL)" instead of "linear" you will get the frequencies below 1 kHz in your plot.  Since the spectrogram plot is linear in the vertical axis, it obscures the frequencies below 1kHz to the point where I'm guessing what the delay on the tweeter and midrange channels should be.  I could guess based on what I see above, but I'd probably get it wrong (I'd guess 3.05 ms added to both the midrange and tweeter channel values to the delays that are already there, but I could be wrong).  You can see the little "dog leg" of the peak energy time curve a 3 ms on the horizontal axis, that's apparently where the bass bin is coming in relative to the midrange, but I can't tell if the frequency is 400 Hz or 200 Hz (where the peak energy time curve will begin to deviate from verticality due to the design of the bass bin itself- which is the minimum phase behavior of the horn/driver). 

 

Here is a screenshot of my settings (both from the "Controls" menu and the "Limits" menu) on top of a spectrogram view so you can replicate what I post:

 

Spectrogram limits and controls settings.JPG

 

You are also showing a great deal of nearby acoustic reflections in your spectrogram.  I'd recommend temporarily placing blankets, quilts, absorption tiles, etc. all over the top of any acoustically reflective objects (and especially the floor between the microphone and loudspeaker) and otherwise within a meter or so of the loudspeaker and microphone, just for the measurements.  This will allow you to get usable phase and group delay information in your REW measurements.  It will quiet the vertical spikes that follow the initial impulse.

 

You can increase the resolution of the smoothing (I've used 1/6th octave smoothing above, but you can use 1/12th or finer smoothing to see a more, albeit with more hash and visual distractions).  If you punch the "Controls" menu button while looking at the SPL& Phase plot, you can also punch the "Estimate IR Delay" (IR is "impulse response" here), then select "Shift IR" to zero the time in the measurement to the leading pulse of the loudspeaker, you will get much better phase plots.  Otherwise, you will get artificially shifted phase plot due to the non-zeroed "0" time point. 

 

Chris

 

After setting the impulse response to 0 and smoothing to 1/6 the graph looks like this.

 

The little dogs leg is at almost exactly 400Hz


Also, the frequency scale is set to db SPL but I cant seem to get the scale to change.

 

2103291262_Spectrograph2.thumb.jpg.57aa1d94d0883b525eadb2d02695d0c8.jpg

 

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Interesting.  Well, you can see where the phase blows-up in the SPL & phase plot (or in the Overlays facility--phase plots), and if you select "generate minimum phase" within the group delay dialog, you will see the same frequencies where the excess group delay curve jumps upward (i.e., later arriving or phase lag conditions).  The number of milliseconds that the excess group delay curve jumps upward (lower in frequency than the crossover point) is the amount of delay that you need to add to the upper frequency channels to bring the bass bin into time alignment.  This is actually more accurate than the spectrogram, but if your room is noisy, you can't see the excess group delay curve very well.  That's why I advocate first looking at the spectrogram plot for setting the delays.  The excess group delay curve flattening through the crossover points is the fine tuning method.

 

Try toggling the vertical axis control back and forth.  There are four different settings that I see in the version of REW that I'm running, and the log (dB SPL) is the one I tend to leave it on.

 

Chris

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