LS-9 and LS-6 digital crossover interest

Syrah · « **Reply #40 on:** 5 Jun 2015, 02:29 pm »

I am excited about this, but I do share bdp24's concerns. In a perfect world, I'd like either a unit like this that has negligable time delay so that it can be confined to the bass section.

I have a vinyl rig and a digital server with DSD capability and a DSD DAC. It seems strange to take those analog signals and then put them through a round of ADC/DAC once more.

Maybe if I had a high end digital phono stage that did ADC and the whole RIAA in the digital domain, and a server that went straight to your DAC keeping it in the digital domain right to the end with only one digital to analog conversion, that might make me more comfortable with the technology.

In terms of vinyl, most reviews that I've read still give the nod to traditional phono stages over those that convert the signal to digital and then do the RIAA curve in the digital domain - although I suspect it's a matter of time before a digital phono stage comes along that's a giant killer.

Any chance this could be DSD capable? I'm using a Chord Qute EX now with a JRiver server and a decent sized DSD collection of music. If this DAC is as good as Danny says (and is better than my Chord) and could do DSD, it would be a real contender.

Thanks!

HAL · « **Reply #41 on:** 5 Jun 2015, 03:24 pm »

Syrah,
Sorry, but the dspMusik is not a DSD DAC and will not be due to the signal processing required. I use it with my DSD DFF files by downsampling to 24bit/176.4KHz PCM in my player. That works very well.

It was compared as a PCM DAC to a EMM Labs DAC2X. The customer that has the dspMusik liked the dspMusik in comparison to his DAC2X. He is the person with the hybrid setup using the dspMusik as the bass management section below 300Hz. woodsyi is a big vinyl person and that setup was an improvement over his original setup.

Does not sound like it is for your system as the crossover point is to high to use it as a hybrid due to the time delay. Sorry it will not work out for you.

Davey · « **Reply #42 on:** 5 Jun 2015, 04:10 pm »

HAL,

You're going to have to attach the drivers to the crossovers to measure/capture the exact electrical response. You are aware of this?

Dave.

HAL · « **Reply #43 on:** 5 Jun 2015, 04:16 pm »

For the NEO8, I can use a resistor as it is a planar.

The woofer is going to be another resistor, but may need a woofer to see the difference in loading.

Starting simply to test the setup.

Would be more fun if I had a pair of LS-9's to measure directly, but this will be a good start.

HAL · « **Reply #44 on:** 5 Jun 2015, 08:21 pm »

First set of crossover measurements completed. Will see what I can do.

rak313 · « **Reply #45 on:** 6 Jun 2015, 12:14 am »

Quote from: HAL on 5 Jun 2015, 04:16 pm

For the NEO8, I can use a resistor as it is a planar.

The woofer is going to be another resistor, but may need a woofer to see the difference in loading.

Starting simply to test the setup.

Would be more fun if I had a pair of LS-9's to measure directly, but this will be a good start.

Can't you trace out the coils and capacitors and draw a circuit diagram to figure out the transfer function?

HAL · « **Reply #46 on:** 6 Jun 2015, 04:59 am »

It is easier to measure the impulse response of the crossover with loads and work from that.

CLIO does the circuit impulse measurement and they are faster to do than building a Spice circuit model with a speaker load.

tubesaab · « **Reply #47 on:** 8 Jun 2015, 06:56 am »

Hello From Denmark

follow this treat with great interest ..because i have used something like this.on my LS9

my first digital crossover was Groundsound 2 ways,,,where i used a Groundsound amp for the bass and my Gryphon Encore amp for the top...it sound really good,,,only problem was ,that my Gryphon amp sounded better than than the Groundsound in all aspect,,,so i could not get the best sound out off the speaker..

next step was to change to passive again,,and upgrade some off the component in the filter,,,

for the bass i use a Jantzhen c-coil with very low resistance ---give me a very dynamic bass

for the neo i change to mundorf supreme caps,,and cross coil all over----all parts with the same value as in the original

Then i use Jriver on my pc ,,and go from usb to my DDdac pcm1794..where i can play hi.res music

the Jriver prog is very nice ,,it have also the same functionality as my former Groundsound digital filter,,,,like room correction and so on

The biggest problem .in my opinion ,is ,the need for to amp in the same quality ,,,remember that the LS9 crossover in a place, where it is important, that the amp is equal good

another important things in digital filter and dacs ,,is the output stage,,,no Opamp is good enough,,,compare to a cap, or trafo, or a good tube output

for now i must say, the sound in LS9 is very very good.....

Best Regards Bjarne

HAL · « **Reply #48 on:** 8 Jun 2015, 11:54 am »

Yes, in biamp situations all the amps need to be excellent sound quality to show the improvements.

The link in my opinion that caused the issue with the Groundsound digital XO is that it uses linear phase reconstruction filter DAC's just like the DDAC. From the units I have researched, no one uses this technique to keep the linear phase process out of the crossover.

It's processing rate is 1/2 the dspMusik and has more time delay through the unit from the spec sheet.

The dspMusik has an opamp based output stage that is DC coupled with very low DC offset. This gives the best bass response of any of the digital filters I have used. Sound quality to me is very good indeed.

Danny Richie · « **Reply #49 on:** 8 Jun 2015, 01:40 pm »

Quote

next step was to change to passive again,,and upgrade some off the component in the filter,,,

for the bass i use a Jantzhen c-coil with very low resistance ---give me a very dynamic bass

for the neo i change to mundorf supreme caps,,and cross coil all over----all parts with the same value as in the original

The Jantzen C-coil is a toroidal style coil wound on a laminated iron core. So you lowered the resistance and picked up some low end output but it will also smear the mid-range. Their coils are also not as advertised. The Copper wire comes from China and is recycled. It averages 94 to 96% Copper. The coil that was on the crossover to begin with was a high quality four 9's pure Copper that was an air core. It was much higher quality than the coil you went to.

Also, the stock crossover used Sonicaps. They are high quality and better sounding than the Mundorf caps you swapped out for.

If you really want some improvements go back to the original parts and add some Sonicap Platinum by-pass caps to the tweeter circuit. This will improve clarity and low level detail by quite a bit.

Davey · « **Reply #50 on:** 8 Jun 2015, 03:07 pm »

HAL,

I think you're confusing folks with your assertions that linear-phase filtering is not desirable....either in the crossover or the DAC portion of these DSP gadgets. Elaboration and some explanation of your point of view would probably be appreciated.
Most users who are in search of information regarding the potential phase characteristics of DSP crossovers, are probably under the impression that linear-phase operation is desirable to minimum-phase operation in all instances.....all other things being equal.

For reference: All DAC's are linear-phase....in the passband (the audio frequency range.) If not, they're not very good DAC's.

"Linear-phase" recon filters remove the phase shift above the limit determined by the sampling rate, but it's questionable how much subjective improvement is gained from that.

Cheers,

Dave.

HAL · « **Reply #51 on:** 8 Jun 2015, 05:03 pm »

Dave,
In the other thread I started for the MS-3 and dspMusik I posted white papers on the subject of why I am not using linear phase filtering in the processing and output DAC used in the dspMusik. Here is that thread:

http://www.audiocircle.com/index.php?topic=132170.0

The DAC's are Wolfson Micro WM8742's for anyone interested. I have selected the minimum phase reconstruction filters for the DAC's in the system, since those sound better to me. It is also using the Apodising filter for the A/D section to minimize the effects of it's linear phase filtering for reconstruction. Those DAC's were developed based on the research in the white papers. The specific part is the pre-ringing in linear phase filters. Minimum phase does not have pre-ringing and from the psycho acoustic testing in the papers the one test subjects preferred.

Those same DAC's have been used in prototypes used at RMAF in a room I know of. Usually reviewers have stated they are state of the art sound quality. Those did not use linear phase reconstruction filters.

In my filter design class in college, filters were discussed as to how the alignment is done. Hence I used the term no linear phase filters. Minimum phase is the alignment used for the DAC filters in this case.

THROWBACK · « **Reply #52 on:** 8 Jun 2015, 09:15 pm »

Danny: May I ask what value of Soniccraft platinum bypass caps you recommend for he LS-9 crossover?

Thanks,
Chuck

Danny Richie · « **Reply #53 on:** 8 Jun 2015, 09:45 pm »

Quote from: THROWBACK on 8 Jun 2015, 09:15 pm

Danny: May I ask what value of Soniccraft platinum bypass caps you recommend for he LS-9 crossover?

Thanks,
Chuck

Technically anything below a .1uF works well. I most often use a .022uF value. It hits a good medium of performance verses price since the smaller values are less expensive.

THROWBACK · « **Reply #54 on:** 8 Jun 2015, 11:40 pm »

Thanks, Danny. I'll order some up.

HAL · « **Reply #55 on:** 9 Jun 2015, 11:46 am »

Anyone else interested in demoing the dspMusik with their LS-9's? I have one system that can be sent for trials.

I need at least one person in the Continental US that wants to demo it so I can verify the digital crossover is correct. I have no way to test it here with speakers. If you are in the MD, VA or DC area, I can setup a demo with your system.

This will be the full HAL MS-3 and dspMusik demo system with TRS to XLR cables, as changes may need to be made and much easier using the Audio Weaver development system on the PC to change things if needed. I just email you a file to load as needed.

So far each demo has been done that way in every system. It is very easy to use and comes ready to play your files with Foobar2000. Just hook up a display, USB drive, keyboard and mouse to the front USB ports and the dspMusik to the back USB port. Connect the XLR connections to source and amps. Then you are ready to play music. If you need single ended connections, I can send TRS to RCA adaptors to use your RCA interconnects.

You can demo the system for 2 weeks to give you time to evaluate the sound quality. Just ship it back to me after the demo time.

In this case it has to be used as the full crossover for the system, not as bass management as discussed above.

HAL · « **Reply #56 on:** 21 Mar 2016, 11:37 am »

First person to try using the MS-3 and dspMusik with his LS-9's is happening.

First he is moding his LS-9's to put the passive crossover outside the chassis. Will be sending CLIO to him to make the crossover measurements and then sending the block diagram for the LS-9's.

In the mean time they will be comparing their MS-1 running Windows 7 to the MS-3 running Windows 10 using the dspMusik as the USB DAC.

KLH007 · « **Reply #57 on:** 22 Mar 2016, 01:49 am »

Rich, What DAC will the dspMusik be compared to in his system?

Syrah · « **Reply #58 on:** 22 Mar 2016, 01:52 am »

I look forward to the results. Such a shame I'm not in the US. I have all external Xovers with LS9s powered by 4 * Dodd 120w. I would have been a good guinea pig for you!

HAL · « **Reply #59 on:** 22 Mar 2016, 02:19 am »

007KLH,
He has both an April Music and a Gary Dodd DAC.

Syrah,
Will keep everyone posted on results. The system shipped out today for trials.