I was looking for a not too expensive multi-channel DAC so that I could experiment with active crossovers in the digital domain using APO equaliser.
The product I purchased is an ASUS XONAR U7. This has quite good specs for a 7.1 DAC and I'm very happy with. It's USB powered and very quiet.
I've implemented a 3-way crossover using Linkwitz-Riley filters which can be implemented in APO by cascading 2nd order Butterworth filters.
The only minor downside is that being such a small device, 3.5mm stereo jacks are required to interface it.
The product I purchased is an ASUS XONAR U7. This has quite good specs for a 7.1 DAC and I'm very happy with. It's USB powered and very quiet.
I've implemented a 3-way crossover using Linkwitz-Riley filters which can be implemented in APO by cascading 2nd order Butterworth filters.
The only minor downside is that being such a small device, 3.5mm stereo jacks are required to interface it.
Yes I did look at minidsp, but it's 3x the price. It has 8 RCAs which is more convenient and I believe it's possible to implement filters in XMOS if you are into programming. What put me off more than anything is that they don't quote any distortion or S/N specs. It also needs an external power supply as the XMOS device is quite power hungry.
I recently tested the Behringer FCA610 (USB+Firewire interfaces) under Linux. I found that I could use it as an 8-out (10-out if you also connected an SPDIF-input DAC). Measurements of the audio outs showed performance was pretty good. On the downside, whenever changing the sampling rate and starting to play there was a noticeable "pop" just as the audio started up. I have also used this under Windows and did not experience this problem. Under ALSA/Linux there are no drivers so all you can do it get data (use the inputs) and send data (use the outputs) but that is just like any other DAC.
New FCA610s go for $199 but you might be able to pick up a used one for $50 less or so.
New FCA610s go for $199 but you might be able to pick up a used one for $50 less or so.
I've been playing with a Behringer UMC1820 from Windows 7, which requires a UAC2 driver. (Newest Win10 apparently has a native driver, at last...) Like your FCA, the UMC pops during initialization, whether boot or changing sample rate. Turning on the amp after boot & resampling everything to 96KHz works okay, though I'm not exactly happy about this sort of thing in 2017.
But I'll live with it for $30ish/channel.
But I'll live with it for $30ish/channel.
I have also used my FCA610 on a laptop running Windows 10 and I there was no pop or it was barely noticeable, at least not enough to get my attention. Under that OS I get a control panel for the FCA610 and maybe this is helping to run it properly.
On the other hand when I tried using it under Ubuntu 16.04 or with the latest Raspbian release on an R-Pi I did get the pop that I mentioned. Not exactly sure if this can be corrected or not - I haven't even tried yet. Your suggestion of turning on the amps after and off before the FCA is the workaround. But I was thrilled to see that the most recent Raspbian image works with it, because I can use it as a multichannel ADC and DAC on that platform, including SPDIF coax and toslink I/O.
On the other hand when I tried using it under Ubuntu 16.04 or with the latest Raspbian release on an R-Pi I did get the pop that I mentioned. Not exactly sure if this can be corrected or not - I haven't even tried yet. Your suggestion of turning on the amps after and off before the FCA is the workaround. But I was thrilled to see that the most recent Raspbian image works with it, because I can use it as a multichannel ADC and DAC on that platform, including SPDIF coax and toslink I/O.
I use the Esi card in my system.
Compared to the Behringer FCA610, the Esi is much better. More stable (as in ROCK stable on win 7), better sound, cheaper etc. I have heard, that the Esi plays way above the asking price. I have not had a chance to A/B with the focusrite scarlett 18i20 - But I tried the focusrite against the FCA610, and I would say that the difference was subtle.
It is difficult to describe sound, but I would say that the Esi sounds natural. Not harsh at all, but not mellow/soft either.
The FCA610 is more sterile in comparison. The Esi simply sounds better. Also the analog in, is not good at all. Second, I have had no luck getting the digital inputs to work...
For the asking price, I dont think there is a better alternative to the Esi. The downside though, is the lack of inputs, mic inputs etc.
Compared to the Behringer FCA610, the Esi is much better. More stable (as in ROCK stable on win 7), better sound, cheaper etc. I have heard, that the Esi plays way above the asking price. I have not had a chance to A/B with the focusrite scarlett 18i20 - But I tried the focusrite against the FCA610, and I would say that the difference was subtle.
It is difficult to describe sound, but I would say that the Esi sounds natural. Not harsh at all, but not mellow/soft either.
The FCA610 is more sterile in comparison. The Esi simply sounds better. Also the analog in, is not good at all. Second, I have had no luck getting the digital inputs to work...
For the asking price, I dont think there is a better alternative to the Esi. The downside though, is the lack of inputs, mic inputs etc.
Just saw your response now. The ESI sounded interesting so I looked at the specs from the manufacturer. I see some problems:
The analog output Level is:
- -10dBV unbalanced
- -10dBV nominal
- +0.5dBV maximum
Even the maximum output of +0.5dBV is only 1.06Vrms. That is too low to drive some amplifiers to their full power, and this is the PEAK/MAXIMUM output! There is zero headroom above this voltage. I see this as a very serious problem, and one that is overlooked too often with DACs.
While the unit can playback audio at 96kHz, the number of channels must be reduced to 2 channels do so: Here are the sampling rate specs:
- up to 8 channel playback at 44.1 kHz and at 48 kHz
- 2 channel playback at up to 96 kHz
Just like the sample rate, the bit depth must be reduced if you want to use all 8 channels. Resolution:
- up to 8 channel playback with 16-bit data
- up to 6 channel playback with 24-bit data
If these limitations are fine for your application then the ESI unit seems like an interesting option. Other specs like THD+N look fine.
On the other hand, the Behringer has inputs (four analog and a SPDIF input) and can make use of all inputs and outputs simultaneously while running at 24/96. I measured my unit and it seems to have low enough distortion and is quiet enough for my needs. It also has almost 2Vrms output capability, so I can even drive pro amps (I am using one in a current build). The Behringer is a great combination of features, low price, and performance that is not equaled in any other product that I have come across.
CharlieLaub:
Thank you for additional information. I use mine in a 3-way configuration with FIR filters via Jriver and Rephase (48 kHz 24 bit) - Both Jriver and Rephase use 64 bit depth resolution, so the loss should be "close to zero".
I have Jriver configured so all sound are either upsampled, downsampled or left untouched to 48 Khz. I find this a good compromise, because I use my system for both CD, youtube etc streaming and video playback.
It took me a long time to pull the trigger on the Esi card, because:
1) I was not sure whether the output (from usb-bus power) was enough. I find the output to be fine. Most of the time I have the output in the Esi control panel turned down 12-14 dB! - So quite some headroom left. My amplifiers is icepower 125asx. I have a small room though (20 squaremeters). For a normal two-way I would say that there is enough headroom. I think my bass-midrange driver would run out of steam If I turn the volume all up - I have of course compensated for baffelstep - Around 4-5 dB.
2) was about the lack of inputs. I have got the analog inputs to work on the Behringer FCA, but I find the sound mediocre. I have not got the digital inputs to work with Jriver - Even if though it should work the way I have done it - ASIO in via Jriver. Have you got yours to work with digital inputs?
I agree that the Behringer is good value - No other soundcard comes near the combination of features vs low price. It has low noise on the outputs - Which is not the case with for instance the Focusrite.
But the sound is not as good as the Esi card, as I mentioned earlier. And it is even cheaper (At least in the EU). I also find the software to be VERY crappy. Both the user interface but also the stability. This of course comes down to personal opinion and system settings. My system is set up to audio, i.e clean formatting and all that. On the other hand, I have had close to zero problems with the Esi card - It just works. The Behringer card is kind of hit and miss IMO.
It have heard that the Esi card perfoms WAY above its price. I do not think for instance one of the "cheaper" RME of Steinberg cards would be much better - soundwise - If better at all. This is of course postulation, because I have not compared them, but I have read about such comparison. If I were to opgrade I would consider one of the MUTU soundcards.
Thank you for additional information. I use mine in a 3-way configuration with FIR filters via Jriver and Rephase (48 kHz 24 bit) - Both Jriver and Rephase use 64 bit depth resolution, so the loss should be "close to zero".
I have Jriver configured so all sound are either upsampled, downsampled or left untouched to 48 Khz. I find this a good compromise, because I use my system for both CD, youtube etc streaming and video playback.
It took me a long time to pull the trigger on the Esi card, because:
1) I was not sure whether the output (from usb-bus power) was enough. I find the output to be fine. Most of the time I have the output in the Esi control panel turned down 12-14 dB! - So quite some headroom left. My amplifiers is icepower 125asx. I have a small room though (20 squaremeters). For a normal two-way I would say that there is enough headroom. I think my bass-midrange driver would run out of steam If I turn the volume all up - I have of course compensated for baffelstep - Around 4-5 dB.
2) was about the lack of inputs. I have got the analog inputs to work on the Behringer FCA, but I find the sound mediocre. I have not got the digital inputs to work with Jriver - Even if though it should work the way I have done it - ASIO in via Jriver. Have you got yours to work with digital inputs?
I agree that the Behringer is good value - No other soundcard comes near the combination of features vs low price. It has low noise on the outputs - Which is not the case with for instance the Focusrite.
But the sound is not as good as the Esi card, as I mentioned earlier. And it is even cheaper (At least in the EU). I also find the software to be VERY crappy. Both the user interface but also the stability. This of course comes down to personal opinion and system settings. My system is set up to audio, i.e clean formatting and all that. On the other hand, I have had close to zero problems with the Esi card - It just works. The Behringer card is kind of hit and miss IMO.
It have heard that the Esi card perfoms WAY above its price. I do not think for instance one of the "cheaper" RME of Steinberg cards would be much better - soundwise - If better at all. This is of course postulation, because I have not compared them, but I have read about such comparison. If I were to opgrade I would consider one of the MUTU soundcards.
@ Rokytheman:
No worries - if the ESI is working for you, that's great!
I have committed to using the Behringer in my system build. It's an active speaker system with the crossover run under Linux on a Raspberry Pi. I can either stream PCM audio over WiFi to the system, or use the analog inputs on the FCA610. I have not tried the digital inputs on the FCA610 yet but I intend to test them. In my Linux system the sample rate must be known ahead of time so that the audio processing software can read in the data at the correct rate. I also up/down sample everything to 48kHz. For testing purposes I have a couple of options: I can use a MiniDSP miniStreamer to stream from a laptop via coax at 48kHz. I also have a MiniDSP miniDIGI which is a hardware ASRC with two coax and two Toslink inputs and fixed 48kHz output. I could connect its output to the FCA610 digital input so that I can accept up to 192k data.
I have not been able to do a critical evaluation of the sound quality of the FCA610. At this point I see its strengths as very low noise and no hum or other interference, lots of inputs and outputs, and ability to make use of them from Linux.
On the downside, the pop from the FCA610 when starting playback (under Linux) is pretty nasty. Luckily I have some software that can turn amps on and off, or connect/disconnect relays, at certain times and I will need to use this functionality to create a start-up and shut-down sequence that will prevent any pops or other noises from reaching the speakers. This might also include LED/LDR muting of the amp inputs. For now I can turn the amps on and off manually, but automating everything is my ultimate goal.
I just got the system up and running with a rudimentary crossover and I am still evaluating everything, including the sound quality from the FCA610. I still have a lot of development in front of me.
No worries - if the ESI is working for you, that's great!
I have committed to using the Behringer in my system build. It's an active speaker system with the crossover run under Linux on a Raspberry Pi. I can either stream PCM audio over WiFi to the system, or use the analog inputs on the FCA610. I have not tried the digital inputs on the FCA610 yet but I intend to test them. In my Linux system the sample rate must be known ahead of time so that the audio processing software can read in the data at the correct rate. I also up/down sample everything to 48kHz. For testing purposes I have a couple of options: I can use a MiniDSP miniStreamer to stream from a laptop via coax at 48kHz. I also have a MiniDSP miniDIGI which is a hardware ASRC with two coax and two Toslink inputs and fixed 48kHz output. I could connect its output to the FCA610 digital input so that I can accept up to 192k data.
I have not been able to do a critical evaluation of the sound quality of the FCA610. At this point I see its strengths as very low noise and no hum or other interference, lots of inputs and outputs, and ability to make use of them from Linux.
On the downside, the pop from the FCA610 when starting playback (under Linux) is pretty nasty. Luckily I have some software that can turn amps on and off, or connect/disconnect relays, at certain times and I will need to use this functionality to create a start-up and shut-down sequence that will prevent any pops or other noises from reaching the speakers. This might also include LED/LDR muting of the amp inputs. For now I can turn the amps on and off manually, but automating everything is my ultimate goal.
I just got the system up and running with a rudimentary crossover and I am still evaluating everything, including the sound quality from the FCA610. I still have a lot of development in front of me.
Update:
I had a little more time to work with the FCA610 and it seems pretty good with low noise. I came up with a workaround for the pop on startup: I have a small script that is automatically run to start up the audio and it just waits a couple of seconds before turning on the amp via a 12V trigger. I use a GPIO pin and a relay to toggle the 12V on and off and it works like a charm.
I had a little more time to work with the FCA610 and it seems pretty good with low noise. I came up with a workaround for the pop on startup: I have a small script that is automatically run to start up the audio and it just waits a couple of seconds before turning on the amp via a 12V trigger. I use a GPIO pin and a relay to toggle the 12V on and off and it works like a charm.
CharlieLaub: Very interesting system!
Yes it is nice that the FCA610 has VERY little noise via the output. Way less than the Focusrite i tried in my system. Though the focusrite may sounded a TINY bit better than the FCA610 (as in almost the same), alone the noise was enough to decide to hand it back to the seller for a full refund.
Yes it is nice that the FCA610 has VERY little noise via the output. Way less than the Focusrite i tried in my system. Though the focusrite may sounded a TINY bit better than the FCA610 (as in almost the same), alone the noise was enough to decide to hand it back to the seller for a full refund.
I thought I would drop a note here about a new DAC and ADC that others might be interested in: the Behringer ADA8200. It's a 24-bit, 8-in/8-out (analog) ADAT unit that can operate at 44.1k or 48kHz. I have this working with a Raspberry Pi 2 using the latest release of Raspbian, updated with the latest patches as of today. I am using the miniDSP USBstreamer usb interface with the ADAT firmware. There are optical connections between the USBstreamer and the ADA8200, so there is no electrical interference. IMHO the sound is pretty good!
Here are some details on how I got this all working:
1. Purchased the Behringer ADA8200 on Ebay. Paid about $150.
2. Purchased the USBstreamer (kit) from miniDSP. About $120 shipped.
3. Downloaded driver and firmware software from miniDSP for the USBstreamer.
4. Connected the USBstreamer to a computer running Windows 8.1 and updated the firmware to ADAT_I2S.
5. Connected the ADA8200 to the USBstreamer and did some test playback under Win8. I explored various options for clock (source=USBstreamer vs ADA8200).
6. Prepared the Raspberry Pi 2 with a fresh install of Raspbian, latest version, and updated it.
The USBstreamer appears under ALSA as a new device which you can play to using a music player (e.g. VLC).
I found that if I set the clock source to the USBstreamer there was a small pop when I started to play a track but this was not the case when I set the clock source to the ADA8200 so I chose the latter. This means that the sample rate is fixed at either 44.1k or 48k and you MUST send audio at that rate to the USBstreamer.
In any case, it all seems to be working and I will do some more listening tests over the next few days. I am currently doing stereo listening with the first two outputs connected to a preamp and headphones. I will test the inputs some time in the future but that is lower on my list.
Here are some details on how I got this all working:
1. Purchased the Behringer ADA8200 on Ebay. Paid about $150.
2. Purchased the USBstreamer (kit) from miniDSP. About $120 shipped.
3. Downloaded driver and firmware software from miniDSP for the USBstreamer.
4. Connected the USBstreamer to a computer running Windows 8.1 and updated the firmware to ADAT_I2S.
5. Connected the ADA8200 to the USBstreamer and did some test playback under Win8. I explored various options for clock (source=USBstreamer vs ADA8200).
6. Prepared the Raspberry Pi 2 with a fresh install of Raspbian, latest version, and updated it.
The USBstreamer appears under ALSA as a new device which you can play to using a music player (e.g. VLC).
I found that if I set the clock source to the USBstreamer there was a small pop when I started to play a track but this was not the case when I set the clock source to the ADA8200 so I chose the latter. This means that the sample rate is fixed at either 44.1k or 48k and you MUST send audio at that rate to the USBstreamer.
In any case, it all seems to be working and I will do some more listening tests over the next few days. I am currently doing stereo listening with the first two outputs connected to a preamp and headphones. I will test the inputs some time in the future but that is lower on my list.
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That definitely works, should you happen to have hardware with a PCI (or even PCI-e) slot... Wouldn't work for an SBC, however, and everything has at least USB 2.0 these days, which has plenty of bandwidth for multichannel audio.
I recently tried to put an Asus Xonar DX PCIe card in a Linux box PCIe slot but had problems so I returned it. I find USB with its plug and play operation to be very convenient and perfect for my needs.
I recently tried to put an Asus Xonar DX PCIe card in a Linux box PCIe slot but had problems so I returned it. I find USB with its plug and play operation to be very convenient and perfect for my needs.
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