Wirrunna
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Posts posted by Wirrunna
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ibigpig,
Is the LaScala still running K-55 / K401 mids and K77 tweeters ?
Recently I used 2 miniDSP 2X4 HDs to triamp my K-Horns. However, I used an Eliptrac horn and B&C DCX464 co-axial mid/hi drivers. ChrisA was a great help and very patient with my beginner questions on using REW. One of the hardest things I found while using REW was getting the x and y axis settings right, sometimes people say to use a particular REW display and when you do it doesn't make sense. ChrisA solved my queries by showing the control panel for the display so I could set the right parameters.
Some more reading for you -
https://community.klipsch.com/index.php?/topic/195572-bc-dcx464-as-the-mid-hi-drivers-for-a-k-horn/&ct=1620012789&_fromLogin=1-
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49 minutes ago, babadono said:
4k output impedance? what?...sure am glad I left that world behind long ago...
What is the input impedance of miniDSP?
From the miniDSP 2X4HD Usr Manual
Analog audio inputs
Unbalanced stereo (2 channels) analog audio on RCA connectors
- Max input of 4V or 2V RMS, jumper–selectable- Input impedance: 10kΩ - THD+N: 0.003% (RCA to USB)
- Dynamic range: 102dB
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Following Claude's strong suggestion for a volume control preceding an N-Core amp I ordered a pair of "FV3 SMD Dact 21 Stepped attenuator 50K Passive Pre-amplifier preamp HIFI audio" to connect between the outputs of the miniDSPs and inputs of the Hypex Ncore NC122MP amps in my tri-amp setup. I chose these attenuators on the theory that being stepped they would be reset-able (by counting the steps from off to the desired volume) with more precision than a standard potentiometer.
Using REW I measured one K-Horn, removed the L-Pads from the mid and hi DCX464 in the Top Hat, cabled the volume control in between the miniDSP and the N-Core amps, set the stepped vol to maximum and measured again. Clicked the vol down one, measure, repeat until the SPL of the mid and hi were exactly the same as with the L-Pad. I expected the SPL to be 1/2 a db or so out and require some dsp gain adjustment but SPL was spot on.
I swapped in the second volume control, set it to the same attenuation as the first and ran another REW sweep. Exactly the same SPL in the mid and hi, so I installed the stepped vol control in the second channel.
I had used L-Pads with the DCX464s to lower their sensitivity and therefore lower the miniDSP noise.
Following on from the opinions on N-Core Hypex amps, the next day I re-arranged the tri amping to use my NAD C725BEE as the mid amp and the N-Core amps for Bass and Hi. After getting the gains adjusted the music sounds a bit warmer, not as dry and sterile as it did with the N-Core amps for Mid range. Time will tell.
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YK Thom,
Ripping your CDs is step 1.
How are you planning on organizing your CD library?
Then, how are you going to play them ?
You are going down a rabbit hole here with a lot of options and pit falls. You need to plan ahead.
Like quite a few members here I went with the Squeezebox server and players, they have kept up and now support most of the streaming services as well as local libraries. A lot of options out there, good luck.
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Langston, thank you for explaining "acoustic" crossover. That is remarkably similar to Chris A's advice but his was in the context of phase growth. I decided to try an "acoustic crossover" between bass and mid.
Got to love DSP, with REW and rePhase I can build a config and load it into the miniDSP, measure it, tweak it, listen to some music and if it sounds awful just start again. I've hardly fired up my soldering iron since I got this little device.
Here is the DCX464 SPL in an Eliptrac horn, brown is raw, green is after EQ, showing natural rolloff (rollup ??) of the driver.
The EQ Target Level is 86db, the 3db down is at 314 - who would have thought ?
Well, the Eliptrac is a 320Hz cut off horn and the DCX464 goes down past 300hz.
So if I want to use an "acoustic crossover" I leave the mid hi-pass out, although I will configure a hi-pass filter at 200Hz to protect the driver where it won't affect the response of the driver.
Also, I remember reading that the crossover in a horn should be at least half an octave from the cut off frequency. What happens with no xo, just rely on the cut off ?The Bass Low Pass should be at 314, but what slope and shape ?
Trial and error showed a bass crossover LR at 24db looked good and measured well.
Bass Green, Mid Red, Blue is the full system with levels adjusted and input PEQs applied.
Last is the K-Horn SPL and Phase with IR Delay adjusted to 0.
Mic at 1m in front and 1.18m high, in other words on the Eliptrac centre axis, 1/6 smoothing.
Limited listening at this stage, but sounds very clear. Mary Chapin Carpenter: One Night Lonely sounds like she is sitting on the wood heater between the speakers. -
Here is a new Q-Sys - https://www.qsc.com/solutions-products/q-sys-ecosystem/processing/core-8-flex/
A half rack width unit, 8 analog ports configurable as input or output, networking and USB connections.
It appears to be able to do all the functions that @gnarly and @Langston are talking about.
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On 6/15/2021 at 1:50 AM, Chris A said:
I actually recommend taking initial sweeps at 90 dB @1m on-axis. The 75 dB number comes from those people using direct radiating loudspeakers that experience significant amounts of compression and modulation distortion. Sometimes you won't see problems in the measurement or amplification circuits until they are turned up a bit to let them "breathe" a little.
The 90db sweep is not quite as socially acceptable as the 75db !
Seeks out the occasional rattle.
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Has anyone run this on Langston's recordings - https://www.libinst.com/Audio DiffMaker.htm
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This old thread may be of interest.....
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On 6/26/2021 at 6:29 AM, Langston said:
With my Khorns the raw response drops above 500Hz (pink trace). This is an outdoor reflection-free measurement using a false wall per Dope From Hope. The green trace is an acoustic 6th order LR low pass, down 6dB at 400Hz. Though the DE750/Tractrix is comfortable with a mirror alignment at 400Hz, I chose 500Hz because I'm running the HF passband about 7dB lower than the bass per my taste.
Langston, I know what a 6th order LR low pass is (36db Linkwitz-Riley) but what do you mean by "acoustic" 6th order LR low pass ?
Also, "running the the HF passband about 7dB lower than the bass per my taste" - doesn't that make the music too bass heavy ?
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4 hours ago, RickD said:
I have Khorns and sit 14-15ft from the speakers. Can you elaborate on first order filters? I am not knowledgeable regarding speaker networks.
I sent Al an email regarding the low volume issue with the Extreme slope networks. He told me he normally listens to his speakers at around 1 watt output. . If the output meters on my McIntosh are to be trusted, my Khorns get quite loud at 1 watt. If needed I can return the ES400 portion and exchange for the Gentle Source version, Al gives a 2 week window to return if not happy.
Rick,
If you sit 14-15ft from the speakers then your room must be quite large and you should be fine with ES networks.
Listeners with small rooms sitting close to the K-Horns by necessity have the volume down fairly low and have reported that the ES networks make the sound "thin".
I sit 13 feet from my K-Horns in a big room and do not think they sound "thin", even at quite low volume.
I don't know how much research you have done on the ES networks or what you are expecting but a couple of old threads may better align your expectations with how they will sound -
the first is when ALK was developing them for S.Fogg
https://community.klipsch.com/index.php?/topic/32872-new-extreme-slope-crossover-requiring-no-zobel/
the next is a discussion where ES networks are put forward as a solution to harshness
https://community.klipsch.com/index.php?/topic/98100-khorn-crossover-capacitors-harshness-problem/
@Deang was very objective in discussions of the "thin" sound of the ES networks in his smallish listening room and hopefully he will chime in.
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Just about anything recorded on Telarc by The Atlanta Symphony and Chorus conducted by Robert Shaw is worth listening to.
Highlights are Beethoven's Ninth Symphony and Verdi's Requiem.
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Chris, the Shift IR makes a significant difference.
What does the minimum phase curve tell us?
The first image is K-Horn bass bin 20 to 700Hz at 89db after EQ in my 10.8 x 6.5 x 2.6 m room.
The second image shows the result of Shift IR.
Edit - The flat black line is Minimum Phase, dotted red line is phase and the black line next to it is Excess phase
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Chris, I kind of understand your technique , but how are you stopping out of band signals going to the drivers?
If I use a 24db LR High Pass on a mid driver then I know that the lower bass signal won't be going through the voice coil of the mid driver. Looking at your Xilica screen shot Dev1 out Ch 2 the yellow trace indicates to me that bass signal is not attenuated and will be sent to the mid driver with associated inter-modulation effects.
What am I missing ?
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Tex, it looks like you need to add another 1ms to get 4ms on the hi and 2.5ms on the mid.
I haven't used a Xilica, but it looks like you need some gain adjustment on 2 of the channels. Is there an output gain adjustment available? I would give the bass +2db, leave the mid at 0db and set the hi to -2.5db
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Tex,
If you added 1.5ms to your tweeter channel to align the tweeter (hi) with the mid, then you add another 1.5ms to the hi to give you 3ms and 1.5ms to the mid.
Then have a look at the plot, then try an extra 0.1ms. In other words step it out until it looks good.
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Texdrone,
Looks like you have the Mid and Hi aligned, so I would start with 2ms for the bass.
Now, on the top right of Spectragraph REW screen there are a bunch of Icons, click on the Limits icon and then click the "Fit to data" field and that will adjust the Y axis to your data and fill the chart without the blue waste of space above 20k. From that you can better estimate the delay required for the Bass.
Another way is to click the GD field which hides in the row of clickable fields that starts with SPL & Phase across the top of the screen.
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On 4/15/2021 at 4:10 AM, tigerwoodKhorns said:
This looks fancy. Not sure what design it is and not smart enough to guess without doing a bunch of reading on the Google, but has mid and tweeter attenuation using the 3636.
Just banged this into LT Spice, set the mid and hi as per mboxler's suggested values (see next post).
Looks like a La Scala 500 / 5800 network to me
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1 hour ago, Ol_mcdonald said:
Now you’ve got me thinking…it would be considerably easier, just build a new motorboard for my existing upper cabinet. Nothing ventured, nothing gained! If I don’t like it I can still build a new cabinet for the MF/HF.Do you plan on using DSP and bi amping your future two way setup? That’s the way I will go to test drive it if I go that way and I am so inclined.
After building my Eliptrac horns I built a new motorboard including Dave Harris Eliptrac tweeter lens.
Then when I bought the second hand B&C DCX464s on a whim I left the tweeter lens installed and then ventured down the DSP path after being unsatisfied with passive crossovers.
At this stage I haven't completed the grill, the new motorboards are sitting in the K-horn top hats. I plan to build a ply frame like the latest K-Horn rather than wrapping the grill cloth around the motorboard and stapling. I'll use velcro to hold the grill frame to the motorboard.
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Langston, I'm looking forward to seeing your measurements and impressions of the B&C co-ax DCX464 in both the Eliptrac tractrix horn and in the B&C ME464 horn.
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What is your bass bin ?
Are you going active crossover or sticking with passive ?
There are new B&C drivers, the DCX464 and DCX462, I have a pair of the DCX464s on a pair of Eminence 1.4 to 2" adapters on my Eliptrac horns with active crossovers.
https://www.bcspeakers.com/en/products/coaxials-hf
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TexDrone,
Before your neighbor Chris A replies, may I suggest some changes in the initial settings measurements.
When I did this for my KHorns, I was very concerned that I might fry a driver, so before I started with the KHorns I hooked up a pair of old AR bookshelf speakers, one to the miniDSP channel I had designated as bass and one to the channel I had designated as mid and familiarised myself with the miniDSP and confirmed that there would be no earth loops or loud clicks. I continued to do this when I started doing the crossovers as well.
Suggestions on Initial measurements -
1.3 - I suggest that you do this using the passive crossover to get a base measurement of the speaker response.
After you place the microphone, measure the height above the floor and the distance from the speaker so it is easy to measure later from the same place.
1.4 Use REW to limit the frequency - Bass 20 ~ 2,000, Mid 200 ~ 20,000, Hi 2,000 ~ 20,000.
Save each sweep.
Here is the write up I did, it needs some editing and fixing up, but starting January 27 I added pdf files where I went into a lot more detail.
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Langston,
You should include the Klipsch "cored 4mH inductor" which is probably a 2304 in your tests.
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Langston,
Look forward to reading your test results. Meanwhile, here is a link to the original thread
edit: another link
https://community.klipsch.com/index.php?/topic/151287-foil-inductors-why-the-new-trend/page/4/
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Active Crossover for La Scala via MiniDSP
in Technical/Restorations
Posted
1bigpig, was the stock '79 LaScala an AA ? I thought they would have been AL3 . I am familiar with ALK crossovers ( see https://www.stereonet.com/forums/topic/118361-k-horn-crossovers-from-ak-3-to-universal-to-es/)
I had changed the K77 to a Crites DE120 and the crossover to 4500 between mid and hi to try and avoid the upper mid harshness at higher volumes, ALK told me to get rid of the K401 horn and use an Eliptrac. That certainly changed the sound and got rid of the harshness and getting phase fairly flat amongst other things brightened up the music.
With the two miniDSP 2X4 HD you could easily change your mid to hi crossover frequency to 4500 if you put in the DE120s .