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[Mitchco]

Hello, I have a 3-way horn loaded (mids and tweets) speaker system and would like to replace the passive XO with Acourate digital XO and have a few questions that I am sure the forum can help me with.  I already use Acourate for digital room correction: http://www.computeraudiophile.com/content/529-acourate-digital-room-and-loudspeaker-correction-software-walkthrough/

The amplifiers I have are DIY Nelson Pass Class A amps and I have to build up a few more to tri-amp.  One question I have is that I presume the mid and tweet amps should have input level controls to match the horn sensitivities to the woofer?

With respect to converters, I am using a Lynx Hilo, which to my ears is very transparent sounding, but will not work in a tri-amp configuration.  Given that I like Lynx products, I am wondering if the Lynx Aurora 8  would work as I require 6 channels for tri-amplification?  Alternatives?

JRiver 18 is my music player and Convolver.  My plan is to plug the analog outputs of the Lynx Aurora 8 directly into the amplifier inputs (with level controls for mids and tweets) and use JRiver's digital volume control. Any drawbacks to this approach?

Best regards,

Mitch

[mwillems]

Hello, I have a 3-way horn loaded (mids and tweets) speaker system and would like to replace the passive XO with Acourate digital XO and have a few questions that I am sure the forum can help me with.  I already use Acourate for digital room correction: http://www.computeraudiophile.com/content/529-acourate-digital-room-and-loudspeaker-correction-software-walkthrough/

The amplifiers I have are DIY Nelson Pass Class A amps and I have to build up a few more to tri-amp.  One question I have is that I presume the mid and tweet amps should have input level controls to match the horn sensitivities to the woofer?

With respect to converters, I am using a Lynx Hilo, which to my ears is very transparent sounding, but will not work in a tri-amp configuration.  Given that I like Lynx products, I am wondering if the Lynx Aurora 8  would work as I require 6 channels for tri-amplification?  Alternatives?

JRiver 18 is my music player and Convolver.  My plan is to plug the analog outputs of the Lynx Aurora 8 directly into the amplifier inputs (with level controls for mids and tweets) and use JRiver's digital volume control. Any drawbacks to this approach?

Best regards,

Mitch

I use JRiver as the crossover in a bi-amped system with horn-loaded highs, and it works great.  In response to your specific questions:

1) There's nothing wrong with having adjustable volume on the amps, but there's no need for it either as JRiver can adjust volume up or down to an arbitrary extent.  I use block amplifiers, and use JRiver's volume control to match the channel volumes.  To be fair, my horn amp is much lower wattage than my mid-bass amp so I only have to adjust the volume four or five dB in JRiver.  But an amp volume control is definitely optional.

2) Many folks on the forum use the Lynx Aurora 8 for exactly this.  I personally use a Steinberg UR824, and it works great (for less than half the price).  Finding a multichannel DAC that's low enough noise for horn drivers has been challenging, and the Steinberg passed with flying colors. It has eight channels of assignable output and nearly equivalent noise performance to the Lynx (based on the specs).  It's also a USB interface.  Check out this thread for more options : http://yabb.jriver.com/interact/index.php?topic=55607.0

3) I plug the analog outs of the steinberg directly into my block amps, and use only JRiver for attentuation/volume control.  JRiver's volume control has been rock solid for me (user error is still a problem, but that's true of any volume control).  A 16 bit signal has a theoretical 96dB of dynamic range (that effective dynamic range can be more, but let's assume 96).  If you're doing really intense digital attenuation with a 16-bit output, you might potentially compromise some of the dynamics in the recording.  But the attenuation would need to be severe and the recording would need to have really extreme dynamic range.  I've never encountered a recording that had much content even sixty or seventy dB down.  And if you're outputting in 24 bits (regardless of the bitdepth of your source), you get an extra 48ish dB "for free", so even if you're attenuating your horns 20 dB or more, you'd be able to reproduce a 16-bit source perfectly.

[mojave]

With respect to converters, I am using a Lynx Hilo, which to my ears is very transparent sounding, but will not work in a tri-amp configuration.  Given that I like Lynx products, I am wondering if the Lynx Aurora 8  would work as I require 6 channels for tri-amplification?  Alternatives?

According to a conversation I had with someone at Lynx Studios, you can use the Lynx Hilo as a 6 channel device and drive amps from the headphone outputs. I had a chance to play with a Hilo a few months ago used it worked fine for 2.1 using both line out and monitor out as 4 channels. I can't remember if its menu screen allows one to do 6 channels, though. You should experiment with this first.

If you go with the Aurora 8, don't ever turn it on/off accidentally without having the amps off. It has the loudest pops of anything I've tried. I also have the Steinberg UR824 and love it. It has minimal pops on on/off (unaudible in my system) with the amps on and it doesn't make any noise when changing sample rates. I'm not using active crossovers, but do go directly to 6 different amps.

My surrounds have an efficiency of about 102 dB so I use the individual channel levels in the Steinberg mixer to attenuate my surround channels. This keeps maximum headroom for the mains/subs in JRiver and the Steinberg. You can save your settings in the Steinberg mixer so the channel levels are always set to the right level. I use internal volume in JRiver for volume control.

If you ever want anything external to attenuate the signal going to the mids and tweeter you can use an SM Pro Nanopatch+. It is a balance passive volume controller and it seems quite transparent. I bought one in case I needed it for an audio GTG when using some high efficiency speakers.

[mwillems]

If you go with the Aurora 8, don't ever turn it on/off accidentally without having the amps off. It has the loudest pops of anything I've tried. I also have the Steinberg UR824 and love it. It has minimal pops on on/off (unaudible in my system) with the amps on and it doesn't make any noise when changing sample rates. I'm not using active crossovers, but do go directly to 6 different amps.

In re the pops: I can hear the Steinberg's power on and off pops in my system (my horn drivers are 113dB at 1 watt 1 meter), but the pops are soft enough that they aren't a cause for concern (the power on pop is about twice as loud as the power off pop, but not distressingly loud).  My amps have a two or three second softstart, so if I turn everything on together with a switch (which I usually do), I never even hear the power-on pop. 

Slightly off topic: @Mojave, I actually bought the Steinberg at your suggestion, and it has more than lived up to my expectations (I was afraid it wouldn't be quiet enough, but it's really perfect, even with 113 dB/watt speakers).  I just wanted to take the opportunity to thank you for the recommendation 

[Mitchco]

mwillens and mojave, thanks! Good info.  My midhorn is 110 db 1W/1m and the treblehorn 114 dB sensitivity and the woofer at 103 dB.

mojave, I left a note on the Lynx forum asking about using the Hilo headphone out.  Thanks for the pointer to Nanopatch.

The Steinberg UR824 looks interesting.  Does it switch sample rates quickly?

re: ..."use JRiver's volume control to match the channel volumes."  Interesting, how to do?  If choosing the UR824, looks like an option to adjust the levels there too...

Thanks again.

[mwillems]

mwillens and mojave, thanks! Good info.  My midhorn is 110 db 1W/1m and the treblehorn 114 dB sensitivity and the woofer at 103 dB.

mojave, I left a note on the Lynx forum asking about using the Hilo headphone out.  Thanks for the pointer to Nanopatch.

The Steinberg UR824 looks interesting.  Does it switch sample rates quickly?

re: ..."use JRiver's volume control to match the channel volumes."  Interesting, how to do?  If choosing the UR824, looks like an option to adjust the levels there too...

Thanks again.

If you mean mechanically how to adjust it, go into JRiver's DSP Studio under parametric equalizer (which is where I do my crossovers and other channel routing), select the "adjust volume" filter and pick the channel you want to adjust and how many dB.  The steinberg also provides similar options, but I "trust" JRiver's internal audiopath more (mostly because I'm more familiar with it).  Either way should work and it's set and forget. 

If you mean how to determine the amount of the adjustment, you'll need a mic or dB meter.

[Mitchco]

If you mean mechanically how to adjust it, go into JRiver's DSP Studio under parametric equalizer (which is where I do my crossovers and other channel routing), select the "adjust volume" filter and pick the channel you want to adjust and how many dB.  The steinberg also provides similar options, but I "trust" JRiver's internal audiopath more (mostly because I'm more familiar with it).  Either way should work and it's set and forget. 

If you mean how to determine the amount of the adjustment, you'll need a mic or dB meter.

Yes, I mean mechanically. I use JRiver's Convolver and Acourate, so not sure how the parametric eq comes into play.  Wrt measuring speaker systems, I wrote his article:http://www.computeraudiophile.com/content/529-acourate-digital-room-and-loudspeaker-correction-software-walkthrough/

[mojave]

Slightly off topic: @Mojave, I actually bought the Steinberg at your suggestion, and it has more than lived up to my expectations (I was afraid it wouldn't be quiet enough, but it's really perfect, even with 113 dB/watt speakers).  I just wanted to take the opportunity to thank you for the recommendation 

You're welcome. I'm glad you like it. I plan on writing a review sometime.

Did you download the latest firmware and get a free upgrade to 176.4 and 192 kHz support?

Firmware V1.00 to V1.50
Added the 176.4 kHz and 192 kHz settings to the sample rate selection. For details on setting the sample rate and limits regarding higher settings, refer to the latest manuals downloadable from the Steinberg website.

[Mitchco]

mojave and mwillems, can either of you confirm that the Steinberg device does automatic sample rate switching?  Also, the tech specs says the ASIO driver is multi-client.  Can either confirm that this is really the case?

I see that Uli is having issues with the Aurora 8 in auto sample rate switching: http://www.lynxstudio.com/forum/forum_posts.asp?TID=4795&OB=ASC
And the Lynx driver for the Aurora 8 is not multi-client.

[mojave]

Yes, the Steinberg does automatic sample rate switching. You didn't ask, but it has asynchronous USB. I don't think the ASIO driver is multi-client, but can test tonight. Where exactly do the tech specs indicate the ASIO driver is multi-client?

You can use the AES16e with the Aurora 8. If the AES16e is set as the master clock then you will have automatic sample rate switching. I believe the AES16e is multi-client with channels 1-8 available for one client and channels 9-16 available for a second client. I haven't tested mine yet, though.

[Mitchco]

Mojave, thanks, I assumed async USB.  Re: m/c ASIO driver: http://www.cubase.net/phpbb2/viewtopic.php?t=101066

Interesting on the AES16e, but that and an Aurora 8 out of my price range I am afraid...

[Matt]

Slightly off topic: @Mojave, I actually bought the Steinberg at your suggestion, and it has more than lived up to my expectations (I was afraid it wouldn't be quiet enough, but it's really perfect, even with 113 dB/watt speakers).  I just wanted to take the opportunity to thank you for the recommendation 

You've got my attention

Is it right that the UR824 only has a software volume, so it's effectively always running at +4dBu (not -10dBu)?  And it's still quiet with 113 dB/watt speakers?

That's really different than my experience with the MR816x:
http://yabb.jriver.com/interact/index.php?topic=77508.0

[mojave]

Mojave, thanks, I assumed async USB.  Re: m/c ASIO driver: http://www.cubase.net/phpbb2/viewtopic.php?t=101066

Interesting on the AES16e, but that and an Aurora 8 out of my price range I am afraid...

Here is my discussion about the driver you linked to:  ASIO Line-in/Loopback for any single ASIO device

I just confirmed that the ASIO driver for the UR824 is not multi-client.

[Mitchco]

Mojave, thanks for the link.

Back to the Hilo for a moment.  It does appear that I can do 6 channels and will try as an experiment.  However, I have been a 2 channel person for so many years, I have no idea how to map 6 channels from JRiver to the Hilo.  Is there a bit of a tutorial on how to do this? (i.e. the JRiver part, I know how to assign in the Hilo).

[Matt]

Mojave, thanks for the link.

Back to the Hilo for a moment.  It does appear that I can do 6 channels and will try as an experiment.  However, I have been a 2 channel person for so many years, I have no idea how to map 6 channels from JRiver to the Hilo.  Is there a bit of a tutorial on how to do this? (i.e. the JRiver part, I know how to assign in the Hilo).

DSP Studio > Output Format > Channels > 5.1 channels.

[bobkatz]

Finding a multichannel DAC that's low enough noise for horn drivers has been challenging, and the Steinberg passed with flying colors.

Really it's not a case of finding the right DAC, as long as the DAC's signal to noise ratio is fine and the power amplifier's signal to noise ratio is fine---there is a solution. With your very efficient speakers, perform the following test:

1) Short the input to the power amplifier with a shorting plug. If you don't hear any noise at say, one meter from the speakers, then the amplifier is quiet enough for your efficient loudspeakers.

2) Connect the DAC to the power amplifier locked to a digital source, but not playing, such as a CD player in stop or JRiver in stop. Just make sure the DAC will produce sound when you do play.  If you now hear meaningful hiss, it does mean that the DAC's noise is audible with your efficient loudspeakers, but all is not lost. Chances are very good there is excess gain in the system. You probably do NOT have to seek another DAC.

3) The solution is to insert an attenuator between the DAC's output and the power amplifier's input. You can build a balanced one by making a balanced "o" pad, very simple to make. Pin 2 of the XLR input to a 2k resistor, pin 3 to a 2k resistor. Then hook the other end of each 2k resistor respectively to each leg of the variable portion of a 5k trimpot. Then hook the 2 trimpot legs to pins 2 and 3 of the output XLR. This is approximately a 6 dB pad and hopefully will not be too much attenuation (if it's too much attenuation another solution has to be devised).   Think of this as a "passive preamplifier".

This is your calibration trim, it will also reduce the noise from the DAC by about 6 dB or more depending on the spl that you calibrate your system to. Most power amplifiers have excess gain and with balanced DACs producing typically +4 dBu at -20 dBFS it's a lot of output, no matter how efficient your loudspeakers are. Setting your DAC to an alternate output level may not be as good a solution either as the external attenuator, depending on the circuit path that the signal goes through when you run the DAC at a lower level. And chances are if you run the DAC at a lower level, with your efficient speakers you'll hear noise again, so once again the external attenuator is the best solution.

BK

[bobkatz]

I said "balanced o pad", but technically I meant a balanced "u" pad.

[Mitchco]

DSP Studio > Output Format > Channels > 5.1 channels.

Thanks Matt.  I did that, but here is the part that baffles me.  Where do I map the output of JRiver to the 6 channels of my Hilo?  For example, in my tri-amp scenario, left and right bass (or channels 1&2) goes to Hilo USB Play 1&2, left and right mid (channels 3&4) goes to Hilo USB Play 3&4, and left and right treble goes to Hilo USB Play 5&6.  This is just for example as I don't know which channels are assigned to bass, mid, or treble as I don't know JRiver's mapping.  Are there pull-down menus for this or a grid?  Once I get the digital signal to the Hilo, I know how to map the 6 channels of analog output. 

I also use JRiver Convolution engine, which will host the 3-way digital XO and room correction FIR filters.  I assume that these are also mapped or is it automatically mapped or?

Best regards,

Mitch

[mojave]

Your convolution software should handle the mapping. Audiolense takes care of it just fine and I assume Acourate would do the same. You can see in the attachment that Audiolense has assigned channels 0-2 for L and 3-5 for R. You can then change the routing order when taking the measurement. In the attached example I changed it so the first two channels are the L & R bass, the next two channels are the midrange, and the last two channels are the tweeter. This is how I would do it with the Lynx so that the same DAC pairs are outputting to the same drivers in each speaker.

If not using convolution, you can manually map channels use Parametric Equalizer and Parametric Equalizer 2 in the DSP Studio. You use Mix Channels to copy L & R to other channels and then add high/low pass filters, level adjustment, delays, etc.

[mwillems]

You've got my attention

Is it right that the UR824 only has a software volume, so it's effectively always running at +4dBu (not -10dBu)?  And it's still quiet with 113 dB/watt speakers?

That's really different than my experience with the MR816x:
http://yabb.jriver.com/interact/index.php?topic=77508.0

Yes, I can confirm that the UR824 only has software/firmware volume and is very quiet with 113dB efficiency speakers, but a key caveat is that I am using it with a fairly low gain amplifier.  However, the UR824's noise performance is rated significantly better than the MR816X, so it's reasonable to believe that it would be lower noise in any system.  It's definitely lower noise than the Asus Essence ST, even though the ST is theoretically rated as lower noise (at least as the ST operates in my PC, others may have better luck).

@Mitchco, you could use the parametric equalizer to adjust channel volume even with convolution, but if you're using convolution to do your channel routing, you would have to position the PEQ module after the convolution obviously.  JRiver let's you choose the order of operations so you can position one of the PEQ modules after the convolution module.  Or you could use the firmware volume (if there is any) in the HiLo to adjust the volume.  Global volume adjustments (adjustments that affect the whole channel) should be frequency response and phase neutral.  Sorry for the late reply, I was out of town over the weekend.

@Bobkatz- I considered using such a "passive pre-amp" solution, and actually constructed an in-line input attenuator, but ultimately my solution was to get rid of the excess gain by constructing a lower gain power amplifier.  Coupled with an appropriately low-noise DAC (the Steinberg), my problem is solved, but your approach would almost certainly serve others in the same position very well.  I found that even with my reduced gain amplifier, some DACs were still producing miserable noise in the speakers: the UR824 is the lowest noise DAC I've heard in person (but also the most expensive).

@Mojave, I did indeed download the latest firmware, although I was unaware of the upgraded capability.  Nice!

[Mitchco]

Mojave, excellent!  That clears it up for me and thanks for the recommendation on the DAC pairs - will try it out.

Mwillems, thanks for info on the PEQ and order.  The Hilo has analog level control on 4 of the 6 analog outs.  I was thinking of trimming the mids and treble using this approach.

Thanks again for everyone's assistance!

[kstich]

This may already be a done deal, but you since you stated in the original post you have DIY Pass amps, why not check out a DIY solution?

I use the Exadevices U2I for Asynchonous USB to I2S conversion and it works perfectly in multichannel mode with JRiver. I have it in 2.1 system right now but it has eight output channels. I have it connected to two Buffalo DACs, one for mid/high with a discrete output stage and one for the low end with an op amp based stage. I would highly recommend this combination. It sounds fantastic. The Asynchronous USB interface made a noticeable sound quality improvement over a high end SPDIF interface with galvanic isolation. The benefits of this solution is primarily that's its a custom solution. I have my output stages gain matched to my amp to get good noise performance (my single ended main amp only needs 600 mV for full scale for the front L/R while my sub works well with 2 V on the amp's balanced input).

It also natively accepts 32 bit digital PCM from J River ensuring negligible loss in fidelity from 24 bit audio even with the digital volume control engaged in JRiver. You also have the option of 32 bit volume control in the DAC itself which works quite well too. Having the ability to change volume through a remote or JRemote on my phone is pretty awesome though.

My future plans include experimenting with Acourate after reading your very well written articles Mitchco. Question, did you like Acourate solution enough to leave Audiolense? I will eventually be moving to active 2 or 3 way with sub, which would work better for that purpose?

On a side note, DSD is off little use in your system, as in mine, and I haven't bothered with that function.

[Mitchco]

kstich, thanks for the pointer to Exadevices U21.  Looks like from the same company that produces: http://www.exasound.com/Home.aspx which has a good reputation for quality sounding DAC's.  Currently, the U21 is on back order and the store does not list a price...  It appears not to have a an ADC, which is required for taking acoustical measurements, but that can be solved too.

Based on Mojave's suggestion above, my existing Hilo should work in a tri-amp scenario as the Hilo has 8 channels of digital I/O over async USB and 6 analog output channels.  I designed a 3-way digital XO in Acourate, and using JRiver's Convolution engine, was able to get it working using the Hilo.  All that is left is to build the Pass amps in which I am waiting on parts from the diyAudio store.  However, if the Hilo does not work out as planned, the U21 looks like an excellent DIY option - thanks again.

Re: Question, did you like Acourate solution enough to leave Audiolense?  Yes.