One DAC to Rule it All

No. Any proof for you is in the listening.

This isn't a simple cable swap. It would mean a lot of rewiring to go back and fourth. I was hoping there would be a consensus as to which way would be better.

The double digital conversion would bug the crap outta me.  How are the reviews of using the DBX as a DAC?  I’d think the OKTO would be the better of the two, but that’s just an uninformed guess.  One thing I’d do is take the DBX out of the system and integrate the subs the old fashioned way and see what you get.  This would take some work obviously, but the prospect of getting a digital crossover out of the signal chain would be well worth it IMHO.  FWIW.

I had been doing it the "old fashioned" way until I got the DBX. I found a great improvement upon sending only 100 Hz and up (48db/oct.) to my main speakers (Reference 3A NEFES II), and just below 100 Hz to the subs (same slope). I wasn't expecting such an improvement in detail, but I must confess it was there. I'm just wondering about the double digital conversion. I truly believe the OKTO to be the better DAC, but it won't do the crossover and other things like parametric EQ. So, it's either both, or just the DBX doing it all.

What is your budget ? My brother has the new DCS Rossini $35k 

land incredible ,but he says he may want their master oversampler 

which mo way I would spend more then a nice car on digital or anything 

my end game dac-preamp is the T+A 200 dac it is only $7200 minus discounts 

that’s one I am saving for ,and a new car. My wife thinks $1k power cord is nuts .

I have been comparing a bunch in our audio get together for digital 

the AQ Tornado -sourse is Very good and just brings the best out of your digital .

In my 2 nd system the Eversolo DMP-A8 is a excellent dac -streamer or under $2k built with judt top quality brand parts and latest AKM 4499EX dacs and matching receiver ,and gen 3 Xmas , the interface app is Excellent ,and is even a SS server up to 4 T , imo Best Buy out there. and with any decent upgrade power cord very good sounding , Anthony Perrotta Consultants , He. gives very good package deals $$ and great service.I will give a rundown on it after full runin ,my friend owns the 6 master edition , which is good but different chipset using Sabre , the top A8 has a true active resistive ladder to relay preamp ,not a digital preamp ishocking all thst for under $2k ,I have a separate freya+ pre with good NOS tubes  which is better but on its own no loss of resolution ,Anyway I just thought I would mention it.

Your setup is pretty unique @koestner

I wouldn’t expect many to have experience with this.
I think the biggest contributor to your listening experience is the DBX unit.
Ever entertained trying a good analog crossover like the Marchand Electronics?

Not saying it wouldn’t influence the sound at all, but pretty sure it would influence it less. Then you can actually get a nice dac and hear an improvement.

I use the DBX DriveRack PA2 to control my subs.  In my opinion you are doing it wrong.  Take one output from your preamp and send it full range to your amp.  Take the second output from the preamp and send that to the DBX and use the software on that to set the crossover and levels etc. etc..  Run the subs with the crossover set to the maximum and set the level to approximate what you want but fine tune with the DBX.  The absolute last thing you want to do is have the DBX in between your preamp and your power amp.  The cheap DA/AD converters in it will destroy the quality of your sound but it is completely irrelevant for the subs.  If you don't have two outputs from your preamp I suppose you could always get a y-splitter.

You system is so convoluted that I'm not sure upgrading a DAC is going to make a difference. When it comes to the audio chain, simpler usually is better. I've heard this proven more than once.

I’m with @soix ​​​​@ozzy62 .  Why so involved?  Now, to play Devils Advocate, I doubt that anyone here has actually heard a setup like yours, and your ears are the ultimate judge, but the conversion back and forth would be enough to drive me nuts 

Convoluted? It's really nothing more than an active crossover (in digital form) splitting the signal between my mains and subs at 100Hz. I realize I could send the full range signal to my main speakers, and just use the DBX to the subs, but as I said I had done that for a long time and recently found that keeping the <100Hz from the main speakers gave me a nice increase in resolution. Other than going to a DEQX Premate to do all these features including the DAC from my server, I don't see any other way to get a 48db/oct. slope out to both the mains and subs for a reasonable cost. Also a 48 db/oct crossover in the analog world would be quite a complex and convoluted thing as well.

I also want to thank everyone for sending in their thoughts. I suppose dipping my toe into the digital realm more than once is considered blasphemy in home audio, but I am getting very enjoyable sound. I am considering the DEQX route as their internal AD/DA are of a higher quality. So even though I am seeking advice, you're all correct in the fact that I just have to try out all these configurations to see for myself. I will experiment and keep everyone apprised.

From my medium technical understanding, the main concern with digital replay is jitter, which is largely a function of timing, followed distantly by sample rates.

A large culprit in jitter is a mismatch or misfit in the clock or something effecting timing, from hardware limitations to design issues to noise from various power sources.

Every truly resolving system I’ve heard had separate, but matched, streamer and ;DAC in a different box with an external or otherwise isolated clock.

Nagra, Lumin, Esoteric would be what I’d be looking at, probably Esoteric for all components.

The only thing I know is that, under certain circumstances, multiple ADC and DAC conversions do not substantially degrade the sound.  I heard a track on a test CD (a Jazz sampler/test signal CD by Chesky Records) that was of a sample of music that had been converted back and forth a hundred times, and the same track that had been converted only once.  I don't think I could reliably tell the difference.  

I don't expect the additional conversion of the OKTO to hurt the sound much, but, then again I don't see how it would help to take a digital signal and convert it to analogue then have an ADC convert it back to digital for processing in the DBX.

That's what I was thinking. Why use the OKTO at all if the DBX can accept an AES/EBU signal from my streamer. That way I will only have one conversion, but I will have to use the 32 bit volume control in my Auralic G1 instead of my Benchmark HP4 preamp. It seems like I will be getting rid of a few pieces of equipment if this works out.

That’s is an interesting question.

the double digital part, I’m guessing could go either way, but I have found for the most part, the simpler the system, the fewer cables, the fewer power supplies the better the sound.

 In the end, your ears will always determine what the best sound is for you.

All the best.

@koestner

I agree that only you will be able to tell if you prefer the sound of the DBX (as a DAC) or your OKTO. I’d try it without the OKTO and perhaps live with that for a few weeks or months.

As I recall, @mijostyn has posted about this in the past and he is a long time user of DSP “preamps” for crossover and bass/room correction. He’s even supporting a very nice turntable with this solution, perhaps he’ll weigh in on this.

I’m still using an analog crossover for subs, however, I am intrigued by the capabilities of digital solutions. And I think they are only going to get better.

I am currently running a similar setup where I high-pass the signal from my DAC to my amp/main loudspeakers, and separately send a signal to my subwoofer. I am also using a DBX solution--however, unlike your setup, mine does not perform additional ADC/DAC to the signal. I am using the balanced XLR output from my DAC to the DBX 223xs active balanced crossover to split the signal at an analogue level, which is then delivered via balanced XLR to my power amp on the high level. You may want to consider this option if you're looking to avoid excessive DAC/ADC conversions in your chain. It sounds great for me, and I agree, relieving the main loudspeakers of the lower frequencies and letting the subwoofer pick them up is a great setup (although in my case, I needed to do it to fix a huge room gain at 43hz--I high-pass the main loudspeakers starting around 70hz and then set the low-pass in my subwoofer's DSP at 30hz plus a -12db curve at 43hz in the DSP's parametric EQ), both are 24db/octave roll-off, and it manages to give me a flat response without excess phase shift since it is a 4th order crossover on both ends. the DBX 223 comes in single-ended version as well.

-Ed

Aqua LaScala

@rhg3 finally found me. Here I am in all my glory.

OK. @koestner the problem is you need a DAC channel in front of every amplifier channel, in your case we are dealing with 4 channels, two subwoofer and two main. The dBx has 6 DAC channels in it. Any additional channels are not required. It is really a small professional PA system unit with features like feedback suppression for microphones. 

Between you me and the woodwork the DACs in the dBx are not so hot. The improvement of a digital two way crossover in managing subwoofers can not be overstated, however I think you need to head in a more streamlined direction. I spoke with the folks at Benchmark recently and they are extremely cost conscious. What they are doing is using a MiniDSP SHD Studio and two of their stereo DACs. They say they are getting terrific results with this. The Studio includes Dirac Live and Streaming. Even more streamlined is getting a full function digital preamp. These usually include an ADC with several analog inputs, some even have a phono stage, bass management, room control and streaming. Examples are the MiniDSP SHD and SHD Studio, Anthem STR, Trinnov Amethyst and my personal favorite the new DEQX PRE series. Prices range from $1300 for the MiniDSP to $13,000 for the DEQX PRE 8. The problem you can run into using separate digital items is they can get confused talking to each other causing jitter. You can handle that with a master clock if the equipment has a clock input. In the past each digital piece had it's own DAC and signals were passed in analog. Now we use much cleaner digital interconnections. Unfortunately that leaves the door open for clocking problems. This problem disappears when the clocking is handled by one piece.

I think you should look into the MiniDSP SHD studio. You have one DAC. Just get another one and you are in business. Should you choose to get one order it with the UMIK 2. It is a much better microphone. Any unit can only be as good as the data you give it.

What subs are you using and what is your crossover point and slope?

My subs are 15" drivers in a 3 ft^3 sealed box. They are powered by a Crown 2500 amp, and the drivers are 4 Ohm. My listening room is large because my home is an open floor plan and the system is in the living room. 

I'm going to the Tampa hi-fi show tomorrow and I will ask around what others are doing too. For now I will stick with the DBX unit to learn all its functions before ditching it for something else. That way I will have more knowledge before embarking down another path. I'm interested in the DEQX units, but they are delaying their release of some new pieces. I don't know why.

@koestner 

I am one of the people testing the Beta programing of the new DEQX units. My Pre 8 is due to be shipped out next week, FINALLY. The first thing that happened was COVID and they lost the supplier of the main processor they were using. They wound up redesigning the units around another, even better processor. It also required revising the programming. All this took two years. Then, a problem developed that required redesigning one of the boards and finally two out of the first 100 units built developed the same intermittent problem. They wanted to make the diagnosis before letting the other 98 units go. They are all PRE 8s by the way. Most people will require only PRE 4s. It is the identical unit without the 4 way crossover. It won't be available for at least another 6 months. So, take your time and play with the dBx. I've been doing the digital thing for almost 30 years starting with a Tact Audio 2.2X and I am still learning. 

Your subs are passives! Did you build them? I have the same situation as you, an open floor plan and passive subs in a large room. Two 15's will do a lot of damage and is enough for a point source system. 

Well, my subs were originally Velodyne DD15', but over time both plate amps broke down and even the one I got repaired broke again. That was it for me, so I opened them up and ran the driver wire to some banana jacks that I installed on the plate amps. So they still look like DD15' (nice glossy black), but they are now passive.

Maybe I'm missing something, but if you go digital into your Driverack, where are you doing your Volume control?  You'd have to do it digitally, before the Driverack. What are your choices of an all digital preamp?

I have done this with a Lynx Hilo (just messing around).... as it does digital routing and attenuation, and has multiple digital Ins & Outs.  It's a very cool studio tool, but sadly does not have remote control.  I did not notice any compromise in performing digital volume control with a 24bit signal path.

@mijostyn This is the first I’ve heard of DEQX. In your opinion, will the DEQX Pre4 outperform the MiniDSP Flex (I have considered that model with balanced analog connections)?

-Ed

@mirolab 

You're right. My Benchmark preamp will not work to control both the mains and subs. Luckily my Auralic G1 server has software volume (32 bit) and works really well through my iPad. As you say I will be just "messing around" with this setup to see how I like it.

@koestner I have a DEQX HDP-5 that I’m planning on selling.  Let me know if you’re interested.  Thanks! 

"recently found that keeping the <100Hz from the main speakers gave me a nice increase in resolution." That part I found myself with various 'full range' speakers, including current Nautilus 805 (which are not known to be weak 'down there' but improved when going from 'full' to 'small' size, cut at 50 Hz)

@eddnog That is not a fair comparison. The DEQX Pre 4 is a $10,000 unit. I will have a lot more to say in a week or so as my DEQX Pre 8 will be delivered this Tuesday. 

@koestner Great solution! I had Velodyne subs way back. Eventually the surrounds fell apart. I kept one to use as a Fish Tank stand. I build my own subs now. I am working on Model 4 at this time. They are four balanced force subs with ultra low resonance enclosures using a total of eight 12" drivers. 

The plate amps in most commercial subs are cheap and the integration is awful with those silly low pass filters. Passive subs give you much more flexibility allowing you to use full two way digital crossovers and your choice of amp.

@kraftwerkturbo Excellent! I seems to be hard to convince people that raising the subwoofer crossover point to 80-100 Hz greatly improves the performance of any speaker. Yes , you use subwoofers to improve your lowest end, but 1/2 the advantage is improving the performance of the main speakers. It requires a full 2 way crossover with time alignment and slopes in the 6 to 8th order range. 

My system isn't as high end as some but I use an analog crossover between the pre and amp for the subs.  Works well with no discernable degradation.  

@emsher22 i do the same thing in my system between my preamp and power amp; I just use a solution that has balanced inputs and outputs, the DBX 223sx.

-Ed

Lyngdorf makes a good processor that is in one box. Of course active crossovers are best but doing all the processing under one brain makes the most sense. There is no way to get the latency correct if you use a stereo , multi sub and surround system in one room.