Wirrunna

Edgar, I have a bit of experience with the B&C DCX464 drivers - https://community.klipsch.com/index.php?/topic/195572-bc-dcx464-as-the-mid-hi-drivers-for-a-k-horn/ and will happily share miniDSP settings etc. , although they have been developed for an Eliptrac.

This post has been edited with a new .pdf file. Rainy day down under today after a few days of 35+C temps, so added a bit to my own instructions on using REW and RePhase. Using REW and rePHASE to create a flat phase crossover for miniDSP 2X4 HD. 1 Use REW to measure and EQ.pdf

Dude, I just looked up the specs on the BMS 4590, that driver at 118db is even more sensitive than the 111db B&C driver I use. I'm sure that the hiss you hear is the same circumstances as my setup. You are cutting the signal level for the super sensitive mid and hi so it is down near the noise floor. After putting the L-Pad in my system I have the mid at +5db and the Hi at +2db. As for the cheerleader's megaphone sound, was it before you applied -10.5db ?

Not quite. In my case the hiss was coming from the miniDSP. The signal chain is Raspberry Pi player >>--> NAD pre-amp >>-> miniDSP output 1 >>-> NAD amp >>-> K-Horn bass bin miniDSP output 2>>-> N-Core NC122MP amp >>-> B&C DCX464 Mid miniDSP output 3>>-> N-Core NC122MP amp >>-> B&C DCX464 Hi Turning up the NAD volume control didn't affect the hiss level but sure did affect the signal from the RPi player. So, I added a 12db L Pad across both the Mid and Hi sections of the DCX464 - hiss all but gone -sticking your ear in the mouth of the Eliptrac you can still just hear it, but I can't from a metre away. Now, when I did a REW measurement the spl from the DCX was down by 12db which required an adjustment of gain in the miniDSP which boosted the signal but not the hiss. So I was assuming that the DSP section in the Fusion amp is adding the hiss just like the miniDSP does. If you have a spare L Pad speaker attenuator you could try it out.

Dude, My miniDSP hissed at me and I spent a bit of Google time and finally came across a reply by Bill Waslo of Liberty Instruments and he suggested an L-Pad. That disappeared the hiss, just had to adjust the gain to compensate. As you can't hear the hiss when it is 9db down, a 9db attenuator should be fine. https://sound-au.com/articles/l-pad-calc.htm#s1 is a calculator I use, I reckon a pair of 4.7ohm 5 watt non inductive resistors should work (calculates to 8.26db). However, you say "it sounds like a tin can" - maybe an SPL plot would explain the problem more.

Ian, How did the replacement K77 go ? I measured it with a multimeter and got 6.8 ohms and a scratchy noise out of it so I assumed it was good to go.

Plug the stereo cable into the 12VDC connector on your receiver and the other end into the "control in" + and - . The "control out" connection is for when you want to daisy chain to another device.

Bubo, I recently set up my NAD amp to turn on a pair of amps in a tri-amp config and I just used a stereo cable, but the controlled amps had stereo plugs. If you just get a cable with stereo plugs and cut one end off and strip the cable, put the shield to the "-" and the core cables to the "+" it should control them.

Dude, I had read either on the miniDSP site or somewhere on diyForums that you use PEQs to flatten the passband, FIR for the xover and phase flattening. Dave A, That you tube link is what I did, but the miniDSP 2X4HD has a different interface.

Deang that is a bit harsh, they give your Jupiter beeswax caps a good write up!

Looking at the frequency plot above I realised it was before applying input PEQs after a full range EQ, so here is the further EQ'd full system, right speaker then left. Chris A and the Dude, I'm interested in your experience with the plate amplifier DSP software. I found that the miniDSP integrates easily with REW and rePhase, however rePhase takes a bit to get your head around and has the ability to make spectacularly bad filters very easily. These N-Core amps are the closest thing to a straight piece of wire with gain that I have encountered.

Further tweaking. Equalisation was an iterative process using REW measurements and the EQ function in REW to calculate the settings then import the REW EQ settings into the miniDSP, run another REW measurement, tweak the EQ settings in REW EQ, import .......... Equalisation is by PEQs in the miniDSP. I picked crossovers at 350Hz and 3,500Hz , the crossovers were set using FIR filters in the miniDSP by rePhase Linear Phase Filters and are Linkwitz-Riley 24db per octave at 350Hz and 3,500Hz. rePhase was also used to flatten phase response. As only 3 of the 4 available outputs of the miniDSP are being used, FIR taps are allocated only to the active outputs. How does it sound ? Well I'm not a speaker reviewer, but there is a noticeable increase in clarity and sound stage and the system can be played quieter than with the ES passive crossovers. I have aimed for a flat response and add a "room curve" with setting bass boost to 2 o'clock on the NAD receiver. I will try some gentler slope crossovers after the holiday season - it is summer down here in Australia and I have family staying for a few weeks.

Subjective test results of European caps, this has been posted several times on the forums but I couldn't see it in this thread - http://www.humblehomemadehifi.com/Cap.html

Ian, Quick fix, send me a PM with your address details and I will put a square magnet K77 with optional Z brackets in a padded bag and post it from the Broulee post office on Monday morning. This will get the K-Horn going, and meanwhile we can explore options for other horns, upgrades etc. and maybe give you an excuse for a ride down the coast. https://community.klipsch.com/index.php?/topic/144700-eliptrac-400-kit-finishing-update/&ct=1557489906 Longer fix, replace the K55 mid horn driver with an A55G and and the K77 with a DE110 and try an Extreme Slope 400/4500 crossover, all parts sitting in a box under the house. Eliptrac assembly instructions.pdf

Ian, I ordered my Eliptrac horns in April -Dave Harris at fastlaneaudio@aol.com, $299US for the kit, $233 shipping for 35lbs of machined mdf. A recent thread - https://community.klipsch.com/index.php?/topic/196538-eliptracs-in-the-house/ I like your knotted pine finish on the K-Horns. Amp I use is a NAD C725BEE receiver pre-out into miniDSP 2X4HD then back to the NAD for bass and to an Audiophonics MPA-S125NC Hypex Ncore NC122MP for mid and hi. With this setup the NAD remote operates the tri-amp system as if it was still just a stereo as the NAD has a 12vDC signal to turn on/off associated equipment that connects to the extra amps via a 3.5mm stereo plug and cable. The miniDSP stays on all the time.

Ian, Ordered the K-Horns new in 1989, they came with AK3 cross overs. Re-capped with a Bob Crites cap kit, then got Bob Crites DE10 tweeters and A55G mid drivers. Built an ALK Universal crossover at 4,500Hz between mid and hi. Then built an ALK Extreme Slope network 400 / 4,500. Then an Eliptrac mid horn and recently added a B&C DCX 464 co-ax mid/hi driver and almost finished tri-amping with a miniDSP 2X4HD - still tweaking. The Eliptrac only needs a new motor (front) board in the top hat, not a complete top hat. I suggest you go for a ride on your bike and have a look and listen. I'm retired so are here most of the time.

Ian, Down at Broulee, on the coast between Batemans Bay and Moruya. I have recently fitted an Eliptrac horn with a coaxial B&C DCX464 to my K-Horns, so have a few spare parts, both original and upgrades from Bob Crites. What crossover did you get ?

Ian, My K-Horns have the connections on the left, I just assumed that to reduce production variation all K-Horns were built the same, i.e woofer access door and terminals always in the same place. Where in Oz are you ?

FIR Filters. miniDSP suggest using rePhase freeware to build linear phase crossovers. There is not a lot documentation available but there are a few hints around. After giving it a go I have settled on LR48 xover filters at 350Hz and 3500Hz. The DCX 424 is rated to 300Hz and is only 2db down at 350Hz in the Eliptrac horn before falling steeply.

jorjen, my understanding is that the DCX462 is a DCX464 with an adapter. I got the DCX464 second hand, so no choice. As a self reward for getting this far I purchased a miniDSP UMIK-1 as my Mitey Mike is probably 25 years old. The two mics were reasonably close with their readings , but the USB connected mic is far more convenient than a mic plus a preamp and then 3.5mm plug. The hiss from the miniDSP has been eliminated by an L-Pad of 18 ohms in series and 8.2 ohms in parrellel with the drivers. Those values were the first 10watt resistors I could find in my parts box that I had 4 off each (2 L-Pads each channel). In the mean time, I have re-read Chris A's guides, explored the miniDSP FIR filters and rePHASE and worked out how to build a FIR filter crossover with EQ for the miniDSP 2X4HD but the limit of 1024 taps per output appears to limit the effictiveness. So I set about to re-measure everything with the UMIK and explore the many crossover slopes available I found that BW24db seemed to work pretty well, eliminating a couple of bumps and holes. Rather than graphs I have attached the REW measurement as a zipped file. The measurement is with the UMIK-1 at 1m on axis with and aiming down the throat of the Elliptrac horn. The crossovers are Butterworth 24db at 400Hz and 3500Hz, delay is 6ms for the mid and 6.2ms for the hi. Levels adjusted for flat response. Next rainy day I will try the FIR filters. Nov 4 Mnt26 Bass 0db 0ms BW24db 400Hz Mid 6db 6ms BW24db 3500Hz Hi 0db 6.2ms BW24db.zip

Hiss in the miniDSP. Dave, I slammed these components together using RCA leads from the box of spares, some have "gold" plating, a couple have tin plating etc. They are a temporary setup stuffed in an old Ikea VCR media stand with the miniDSPs sitting on top of the n-core amps. Cable routing is not optimum! I suspect some of the hiss will be induced by having the digital gear too close. When I first heard it I thought the noise was the fan in my Asus Zen Book laptop but then realised it was coming from the speakers. The noise disappeared when I put the B&Cs on back on the L-Pads I was using with the passive xover. I will follow it up later as I was having too much fun playing with the DSP. The L-Pads knock about 8db off. Early testing was done using an old pair of AR 18BV speakers just to make sure that there were no earth loops, loud clicks when the amps turned off etc and the hiss was not audible, but the ARs are probable mid 80s db/W while the B&C is 112 db/w in a horn. A speaker with that sensitivity is going to expose any inherent noise in the amplifier chain.

Spectrogram - scale -3 to 20ms to show delays - M040L Full System - Spectrogram Full system after input PEQs applied and delays and gain adjustments. Jul 16 M083R2 Full System Input PEQs Bass -3.5db 0ms Mid +5.5db 6.9ms Hi -1db 13.9ms.jpg - IR delay of zero

rePhase contd. Now for all drivers. SPL and phase - M040L Full system - the phase will clean up after time alignment GD or Group Delay - showing Hi at 0ms (Y axis), Mid at 7ms and Bass at around 14ms. M040L Full system - GD

rePhase - I have used rePhase to do Linear Phase Filters for crossovers at 350Hz and 3,600Hz, LR slope 96db and to adjust individual driver phase

This is a re-write of going to active crossovers on a B&C DCX464 to an Eliptrac horn in the tophat in my K-Horn The B&C DCX464 is a 1.4" driver requiring an adapter to mount it on the Elliptrac - https://www.parts-express.com/eminence-ha14-2-1-1-4-aluminum-horn-adapter--290-5626 Here is a recent REW plot of the Left K-Horn. This is the current working config. The rest of these posts attempt to tell how I got to this response. These measurements are taken at 1m from the centre of the Elliptrac using miniDSP UMIK-1 and 1/6 smoothing. Equipment. Sources are FM Tuner and a Squeezebox server with Raspberry Pi based streamers feeding a NAD C725BEE Receiver. REW is run on an Asus laptop feeding the AUX input on the NAD. To do the crossovers I have 2 miniDSP 2X4HD and a pair of https://www.audiophonics.fr/en/power-amplifier/audiophonics-mpa-s125nc-rca-stereo-class-d-power-amplifier-ncore-2x125w-4-ohm-p-12756.html for mid and hi amp channels, the bass is done by the NAD. Due to noise on the line outs from the miniDSP the DCX464 is attenuated by an l-pad of 22 ohm in series with each driver and 8.2 ohms in parallel. I first tried the l-pad resistors the other way (8.2 in series) but while the noise was reduced it was still audible at 1m. When SPL and phase are sorted I will experiment with different gains in the equipment chain. The K-Horns are in a room 6.5m wide, 10.8m long with 2.6m ceilings (height). The process I used for each driver : 1. Measure SPL and phase 2. EQ to flatten the SPL. 3. Measure the flattened (PEQed ?) SPL and phase 4. Load the PEQed measurement into rePhase 5. Use rePhase to set the crossover and flatten the phase 6. Measure the rePhased SPL and phase. Then when happy with measurements of individual drivers, run the system with all drivers : 7. Run a 20-20,000 sweep for all drivers for SPL and phase. Determine gains needed. 8. Display GD to see needed delays and also Spectrogram to confirm. 9. Apply gains and delays in DSP and re-run sweep for SPL and Phase. 10. Examine phase response and go back to step 5 and fix recalcitrant drivers. Also fine tune SPL. Experiment with driver invert. 11. When happy with combined SPL run EQ to fix SPL anonamilies and apply to the input PEQ. 12. Confirm SPL and phase and play some music. Notes : All measurements were taken with a miniDSP UMIK-1 calibrated microphone positioned 1 m from the Eliptrac centre at a height of 1.18 m. All graphs are smoothed to 1/6. Raw measurements. Jul 14 M051R1 Bass 20-700 90db Raw.jpg B&C DCX464 Mid in Eliptrac Horn - Jul 14 M063R1 Mid 200-7000 90db RAW.mdat B&C DCX464 Hi - Jul 14 M071R1 Hi 3000-20000 Raw.mdat Now to EQ K-Horn - EQ Jul 14 M051R Bass 20-700 90db TL89db 20-500 1db Equaliser: miniDSP 2x4 HD Jul 14 Filter 1: ON PK Fc 36.05 Hz Gain 5.20 dB Q 5.803 Filter 2: ON PK Fc 42.00 Hz Gain -6.10 dB Q 3.846 Filter 3: ON PK Fc 69.80 Hz Gain 2.80 dB Q 2.002 Filter 4: ON PK Fc 91.00 Hz Gain -4.30 dB Q 3.266 Filter 5: ON PK Fc 132.0 Hz Gain -5.00 dB Q 4.573 Filter 6: ON PK Fc 159.5 Hz Gain -5.30 dB Q 5.218 Filter 7: ON PK Fc 210.0 Hz Gain 14.40 dB Q 5.712 Filter 8: ON PK Fc 239.0 Hz Gain -7.70 dB Q 4.130 Filter 9: ON PK Fc 282.0 Hz Gain 2.70 dB Q 6.892 Filter 10: ON PK Fc 355.0 Hz Gain -1.80 dB Q 8.950 B&C DCX464 Mid - EQ Jul 14 M063R1 Mid PEQ TL86db 330-4000 1db 1on6S.txt Equaliser: miniDSP 2x4 HD Jul 14 Filter 1: ON PK Fc 422.0 Hz Gain -2.00 dB Q 8.662 Filter 2: ON PK Fc 466.0 Hz Gain 2.00 dB Q 10.000 Filter 3: ON PK Fc 548.0 Hz Gain -3.40 dB Q 8.148 Filter 4: ON PK Fc 771.0 Hz Gain -4.90 dB Q 5.059 Filter 5: ON PK Fc 1065 Hz Gain -4.70 dB Q 6.909 Filter 6: ON PK Fc 1318 Hz Gain -2.50 dB Q 5.577 Filter 7: ON PK Fc 1712 Hz Gain -4.70 dB Q 3.909 Filter 8: ON PK Fc 2047 Hz Gain -3.80 dB Q 2.607 Filter 9: ON PK Fc 2800 Hz Gain -2.80 dB Q 4.412 Filter 10: ON PK Fc 3810 Hz Gain 3.00 dB Q 10.000 B&C DCX464 Hi - EQ Jul 14 M071R1 Hi TL 84.5 3600-20000 1db Equaliser: miniDSP 2x4 HD Jul 14 Filter 1: ON PK Fc 3600 Hz Gain 2.00 dB Q 30.000 Filter 2: ON PK Fc 4180 Hz Gain -1.70 dB Q 10.000 Filter 3: ON PK Fc 5030 Hz Gain -1.20 dB Q 10.000 Filter 4: ON PK Fc 5650 Hz Gain 5.10 dB Q 15.000 Filter 5: ON PK Fc 7000 Hz Gain -1.00 dB Q 10.000 Filter 6: ON PK Fc 8800 Hz Gain 0.50 dB Q 8.000 Filter 7: ON PK Fc 10000 Hz Gain -2.00 dB Q 1.000 Filter 8: ON PK Fc 12200 Hz Gain 2.00 dB Q 15.000 Filter 9: ON PK Fc 14130 Hz Gain -1.50 dB Q 10.000 Filter 10: ON PK Fc 17380 Hz Gain 3.00 dB Q 20.000