Robbie010
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Posts posted by Robbie010
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Now that I have gone active with my clone La Scala, overall sensitivity and crossovers are no longer a concern and a world of driver options has opened up to me.
I have already installed Crites CT120 Tweeters, which has given the top end a real boost and clarity.
This has got me thinking..... is there a drop-in 15” woofer driver on the market that will replace the stock K33’s and get me closer to 20Hz without needing physical alterations to the cabs? -
53 minutes ago, Chris A said:
I'd have to look at that .mdat measurement file and your FusionAmp project file to understand what is occurring. It looks like there is a doubled output of the midrange and tweeter above 3 kHz. PM me and I'll send you my email address.
Chris
PM sent, Chris. Thanks.
A little more playing around with the gains and delays has got me to this point:
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2 hours ago, Chris A said:
One metre. The only time you might take a measurement at the listening position is when measuring well below ~100 Hz (subwoofers mainly) but not above that frequency. The issue in that case is being in the extreme near field of the loudspeaker due to the very long wavelengths at those low frequencies will affect the measurements. In general, I take measurements almost always at one metre.
Chris
Hi Chris,
See the new spectograph below, this has been done with only the basic crossover filters applied but I'm struggling to smooth out the kink at 3,000Hz and there is the small dogs leg between 200Hz & 400Hz. Is there any insight you can gain from the graph??
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17 hours ago, Chris A said:
With the Hypex FusionAmps, I would first dial-in the crossover filter slopes and the delays, then start to work on flattening the SPL response. When you run a measurement sweep with each individual channel (all the PEQs reset to zero_, then you can use REW to find the suggested PEQs to add to flatten the response. You can use the thread that I linked on the first page of this thread for that portion).
With the Hypex FusionAmps, they apparently have no input channel PEQs, so you'll have to run individual sweeps of the woofer, midrange, and tweeter and produce a nominal -3 dB of each driver just at the center crossover frequencies (nominally 400 Hz and 4.9 kHz, or whatever you actually chose).
Once you get the individual drivers/horns flattened and carefully attenuated to about -3 dB at the crossover frequencies, then run a sweep with all three drivers playing, then you can set the individual channel gains to bring all three driver channels to the same SPL level, and set any remaining PEQs to further flatten the response.
With the exception of attenuating room modes, it is possible to achieve ±1.5 to ±2 dB flatness (using REW's psychoacoustic smoothing) from about 70 Hz to 16-18 kHz. Once that is done, you've got the 99% solution in hand.
If you've flattened the SPL response after setting the delays and crossover filters (the SPL response will change), then it's time to listen. If you want any further fine tuning, you can PM me for my email address to send the measurement files (*.mdat).
I think you'll find that they sound a lot different now--and better--with the time alignment much closer and the SPL response flat on-axis. You should have a very large soundstage and balanced timbre for your best quality recordings.
Chris
Thanks, Chris. I’ll drop you a line for the email address, it will be interesting to get an opinion on the filters.
When it come to dealing with the delays, is better to use a full frequency sweep done at 1m or at the LP?
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I had a play around today with the spectograph and delays in the new version of REW and managed to get to here:
I'm not sure where to go from here, even small changes to the timings seem to make the spectograph worse from here........
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2 hours ago, Chris A said:
V5.20 Beta 61 presently. The beta version of REW really isn't what I'd really call beta--its more mature than that, and many of the better features reside in that version, leading the "released" version by a year or more.
Thanks, Chris. I've downloaded the beta.
I've just re-read your basic guide (below) and I think I may have gone wrong at the outset.......
I started from scratch this morning and the process I went through was as follows:
First, I loaded the basic crossover points for each driver, first order 400Hz low pass (inverted) for the woofer, first order 400Hz high pass for the midrange and first order 4,500Hz high pass for the tweeter. All good.
I then set the umik mic at 1m from the speaker, at my listening position ear height for the woofer and took a sweep within a limited frequency range of 20Hz - 2,000Hz and flattened its response using REW. I then did the same thing for the midrange, mic at 1m from the midrange horn, sweep between 200Hz - 8,000Hz and flattened the response and again for the tweeter, mic at 1m from the tweeter, sweep from 1,000Hz - 20,000Hz.
However, I struggled with the levels. Prior to making each individual sweep, I tried to set the levels for each driver at 75db using the pink noise test tone in REW and I used the volume control on the plate amplifiers to level match as far as practical. However, whenever I used my digital sound meter at the mic location to confirm the levels, they were all over the place.
What is the correct way to complete these first steps? Should I to set the level with all drivers playing and then simply mute two of the drivers and run a sweep on one driver at a time, without any further level changes, or was my method the right way to do it?
🥴
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18 minutes ago, Chris A said:
You can magnify into the group delay vertical scale so that the most minor divisions are 0.5 milliseconds (500 microseconds), then you'll be at about the right level to see group delay clearly. Right now you're zoomed out to the 50,000 foot level. The control is on the upper left hand of the plot itself when you place the cursor in the plot area, and you will see the scale controls light up when you do.
Yes, the tweeter delay is much closer, but the excess group delay curve --when zoomed in to see the 500 microsecond tick marks--will tell you what you need to know to fine tune the delay settings. The phase curve in the SPL & Phase plot will also get much better, but probably will still extend out of the boundaries of the vertical scale, even when zoomed all the way out.
Don't be afraid to "split hairs" trying to get the delay just right, as I've found it does have an effect (though very small) on sound quality. I try to get the midrange-bass bin delays good to the nearest ~0.05 ms, and the tweeter to midrange crossover within ~0.005 ms (or less depending on the frequency at crossover--which can be a significant phase shift if not right).
And yes, the ear can hear this stuff over extended listening times...believe it or not. If I can hear it, then I'm sure others can too (i.e., I don't really have golden ears).
Chris
There must be some differences between my version of REW and yours, I can't get my scales to match up to yours at all. What version of REW do you use?
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Ah Ha! 😃
Here is a new graph with a 1.5ms delay added to the tweeter......... it looks to like a further 0.5ms may bring that further in line, which I assume is what I'm aiming for!?
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8 minutes ago, Chris A said:
This looks like you need to add ~1.5-2 ms delay to the tweeter. Look at the excess group delay plot to see where the curve is plateauing below the ~6 kHz crossover point.
Its going to take me a while to get to grips with all these graphs and how to read them...... here is the group delay plot:
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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:
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.
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Help! 🤪
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:
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I'm sure its a silly question but here we go........what effect can cabinet fillings have on the frequency response of a speaker??
Can adding a filler material to a bass cabinet have a substantial effect on the lower frequency response of a speaker, such as the la scala. More specifically, could one use cabinet filling to help deal with speaker boundry issue?
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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?
Hi Chris! Me again..........😄
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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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:
Any guidance on whether this null can be corrected using the HFD software and how would be much appreciated!
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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! 😃
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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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?
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!! 🙁
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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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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.
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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! 😃
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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I am just starting to dial in the DSP settings for my clone La Scala but when I read various threads online, I am seeing variations in the mid to high crossover point, some saying 4000Hz, some 4500Hz and some saying 6000Hz.
I appreciate that I can tweak this to my hearts content, as and when I am comfortable playing around and measuring but what is the accepted norm for this crossover point?
Thanks
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I am just attempting to dial in the basic setting on the DSP plate amps for my la scala, the first section asks for the impedeance and the maximum power handling of each driver.
I am ok with the impedance but what is the max power handling of the K33E, K55V and the K77M?
Out of the box, the amp provides 125w for the woofer, 125w for the midrange and 100w for the tweeter. My initial thought was to leave the woofer channel at 125w, maybe 100w for the midrange and 50w for the tweeter?
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I have taken the plunge and bought Hypex NCORE FA123 DSP plate amps for my clone La Scala........... However, I am an absolute DSP newbie.
I have taken some Umik measurements of the in-room response, but I would welcome any guidance / pointers on the basic DSP settings I should implement.
This is the basic graph with a Psychoacoustic smoothing applied:
I would welcome any pointers on where to start here, however, please keep it simple........
I was initially going to follow the guide below on setting-up a basic 3 way crossover with my specific plate amp, but I would really appreciate input from anyone who has advice.
https://www.diyaudio.com/forums/class-d/333733-setting-fusion-amp-3-step-step.html
Are there any pre-set filters that I could use?
Also, I see a lot about "house curves" if anyone can enlighten me?
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I bit the bullet and went with the FA123 plate amps....... Watch this space!! 😃
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4 minutes ago, Chris A said:
I'd actually recommend using these FA 122s or FA 123s on Jubilees and the K-402-MEH, for instance if everything performs as advertised. It certainly will clean up the clutter of my rack mounted D-75A amplifiers, eliminate the need for a First Watt amplifier (a class-A room heater) driving the K-402/TADs, the Xilica XP crossover, the miniDSP 2x4 HD, and allow me to finally eliminate my AVP in favor of a PCIe-to-AES digital-to-digital conversion card (like the RME HDSPe AES card running in a desktop PC).
I'm thinking I'll go with the FA123, as this can do both 2 way and 3 way and gives a little more flexability.
One of the main things that has put me off going down the DSP route thus far is the thought of all the extra boxes - pre-amp, DSP box, multple power amplifiers etc etc. This unit seems to eliminate all that hastle.
La Scala - Change of Woofer??
in Technical/Restorations
Posted
Thanks to all for the responses.
Can I ask what subs you are using @baron167?