miniDSP Tide16 - Holy Grail with 16 Channel Atmos/DTS:X, high SINAD

[rzrike]

I also got a bit tripped up by their comment, but it is true that if using solely digital volume control then the DAC noise level would be fairly fixed regardless of whether the DAC is at quiet output or loud. If the noise is fixed then turning down the signal would bring the two closer together, making the noise/hiss audible after 26dB of amplification.
Analog volume control is usually preferable for quality for this reason, it allows the signal at time of creation to put maximum distance between itself and the noise floor, where you then bring both down to the desired level afterward. AVRs and some AVPs do this, block diagrams (when published) will indicate.

Ironically after doing some of the napkin math on ideal gain staging (@mdsimon2 did this above, great work!) I ended up warmer on AVRs. I hate to come to the conclusion that using high performing gear like miniDSP and Hypex amps can result in worse performance somehow, but I can’t see a way to very easily manage analog volume control in these types of setups.

Yes, the hiss on my system is very likely the DAC noise floor. It doesn’t matter what source the HTx is set to (it is still present if there are no sources physically connected at all), and it is the same level no matter what the digital volume is set to. The only thing that cuts the hiss is a device with analog volume control (like my Topping A90 Discrete) or a voltage attenuator (like the ones I got from Sescom). The results with the voltage attenuators are the reason for my understanding of the HTx always being 4V out of TRS balanced. Given the hiss is cut by a voltage attenuator, I concluded the hiss is contingent on the voltage. Given the hiss remains the same level no matter the volume the HTx is set to and no matter the input device, I concluded it is somehow always 4V out. Possibly the DAC noise floor is at a constant level while the rest of the signal is not; I have no idea.

I don’t intend to pretend to have an understanding of the engineering whatsoever. This is just the conclusion I came to from my own tests and after about 50 emails with miniDSP, VTV, and Deer Creek.

I am satisfied with my current set-up after purchasing the voltage attenuators. It’s maybe a little awkward having my L/R piped through my Topping A90 Discrete (it is after the HTx in the chain), but it adds two advantages: I can boost the L/R on the fly when I feel like it (I like to do this when watching basketball since they mix the commentators too high), and I can change the Topping to its headamp mode to use headphones.

I just wanted to put a comment in here about my experience with using the Hypex MP amps with an HTx and how that might reflect on using the amps with a Tide16. I’m likely to get a Tide16 myself in a year if reviews go well.

Side note: are you saying traditional AVRs like my Denon X3700H use analog volume control? I wasn’t aware of that; just assumed it was digital.

 

[TimoJ]

Side note: are you saying traditional AVRs like my Denon X3700H use analog volume control? I wasn’t aware of that; just assumed it was digital.

It's an analog volume control IC that is controlled with digital bus signals. It's not a multi-gang potentiometer anymore. For example, the HTP-1 uses Cirrus Logic CS3318 chips.

 

[PGAMiami]

We can argue whether Dirac ART, Trinnov Waveforming or an Audiolense convolution filter is best. But what’s certain is that below the Schroeder frequency (200-300hz for most rooms) the room modes dominate, not the speakers and certainly not electronics or silly things like cables. There will be nulls and peaks whether you have Wilson or Radio Shack speakers. Each one of these DSPs deals with the room effects differently, but they all do what room treatment can’t do at lower frequencies. If you want to see what can be done with Wilson using Audiolense, check out what Chris has done on his site audiophilestyle.com. I’m using Dirac ART now but I also have used Audiolense. I think in my case Dirac is better. All these DSP work for 2 channel and immerssive. In the case of ART, it will use all your speakers to smooth out the bass. On two channel music you will only hear two channels but all the speakers will be producing and sometimes absorbing sound so the bass is best it can be in your room.

 

[PGAMiami]

Yes. Physics is physics. I spent decades trying to get things right. Had all the name brand gear, Wilson, Cello, Levinson, Spectral, MSB, Pass, Quad, Dunlavy, Magico, Berkeley. You name it. And tried ASC Tube Trap and RPG. Also digital tools like Z System. Nothing really improved things in a meaningful way like properly done modern DSP.

 

[markus]

Have you opened it and checked how these capacitors are doing? Still looking normal or with tops bulged and leaking?
View attachment 507833

Many thanks for inspiring me to excavate my amp from its cozy rack habitat

Where are those bulged and leaking caps?

 

[TimoJ]

Many thanks for inspiring me to excavate my amp from its cozy rack habitat

Where are those bulged and leaking caps?

Looks good! How does your amp's top cover/panel look like? Is it perforated?

Here is an example how those capacitors could look when air circulation is not properly done:

Nord MP NC252 SE Amplifier Review

Thanks as always Amir. I wonder how many customers have received units in this condition without realising it.

www.audiosciencereview.com

 

[markus]

Looks good! How does your amp's top cover/panel look like? Is it perforated?

Here is an example how those capacitors could look when air circulation is not properly done:

Nord MP NC252 SE Amplifier Review

Thanks as always Amir. I wonder how many customers have received units in this condition without realising it.

www.audiosciencereview.com

KJF Audio MA-01 Review (Multi-channel Amplifier)

This is review and detailed measurements of the KJF Audio MA-01 6-channel Amplifier populated with Hypex NC252MP stereo modules. It was kindly sent to me by a member. I configured it using their online tool and it shows a cost of US $1,868. Not much to see or talk about as far as the case...

www.audiosciencereview.com

 

[TimoJ]

KJF Audio MA-01 Review (Multi-channel Amplifier)

This is review and detailed measurements of the KJF Audio MA-01 6-channel Amplifier populated with Hypex NC252MP stereo modules. It was kindly sent to me by a member. I configured it using their online tool and it shows a cost of US $1,868. Not much to see or talk about as far as the case...

www.audiosciencereview.com

Having dual fans explains it.

 

[markus]

Having dual fans explains it.

Not really. They never come on.

 

[peng]

the HTx always being 4V out of TRS balanced. Given the hiss is cut by a voltage attenuator, I concluded the hiss is contingent on the voltage. Given the hiss remains the same level no matter the volume the HTx is set to and no matter the input device, I concluded it is somehow always 4V out.

Now I can understand why you might think that, but it is not possible! If you want to prove it, you just need a cheap multimeter and measure the output, if it does output 4 V even with no input connected you should contact miniDSP, they usually respond within 48 hours. Something else is causing the hiss you are hearing, wish I was there to troubleshoot it but..

Think about this another way, if it outputs 4 V all the time, how could you be hearing music, or even hiss, the SPL (sound pressure level) would have been dangerous high and damage your hearing already, when you connect the "4V" to your power amp and speakers.

I would suggest you take the time to find the real issue, there are simple enough steps that may take time, but you will be able to find the culprit.

 

[Sokel]

Now I can understand why you might think that, but it is not possible! If you want to prove it, you just need a cheap multimeter and measure the output, if it does output 4 V even with no input connected you should contact miniDSP, they usually respond within 48 hours. Something else is causing the hiss you are hearing, wish I was there to troubleshoot it but..

Think about this another way, if it outputs 4 V all the time, how could you be hearing music, or even hiss, the SPL (sound pressure level) would have been dangerous high and damage your hearing already, when you connect the "4V" to your power amp and speakers.

I would suggest you take the time to find the real issue, there are simple enough steps that may take time, but you will be able to find the culprit.

Yep.
It's bizarre even to think about it, to output 4V of what? AC? At any freq above 20Hz-30Hz one would know REALLY well.
The hiss is probably at the uV range but I'm still surprised by it, minDSP is all about low noise and measurements (well, at least when they don't mess DSP) .

 

[peng]

I have the PC version of DIRAC live / DLBC and I have to use 44.1 or 48 sampling for measurements or the HF will be way off (low). Not sure why there would be any concern about using 48 KHz sampling for any purpose as you cant hear frequencies anywhere near 24 Khz and the lower sampling rates saves a lot of processing power.

Most, if not all people are prone to Placebo effects and different sorts of biases, so if given enough reasons (including those not applicable), they would believe what they heard, thought they heard regardless. It is like believing and hearing even power amplifiers with verified audio specs that indicate transparency for normal humans still have audibly different sound signature described in a spectrum of cold to hot, sound stage from narrow to wide, dry to soaking wet, soft and sweet to crisp and punchy, etc etc..

So yes, they can hear >>24 kHz, and often mentioned more "air" as proof..., probably because some professional reviewer started saying so long time ago so that one has taken root.

Take a look of the following, bs (I trust he truly believe it, so unintentional bs):

miniDSP Flex HTx Digital Audio Processor Review - HomeTheaterHifi.com

Hong Kong-based miniDSP has been manufacturing affordable, high-performance audio DSP(digital signal processing) products for the past...

hometheaterhifi.com

To ensure an apples-to-apples comparison, I set the Flex’s configuration to match that of my miniDSP 4x10HD by manually copying the parametric eq “biquad” and crossover settings from my 4×10 to the Flex HTx using the miniDSP Device console. Once configured, I gave the system a listen using the “direct” mode on my Meridian G68 and a variety of high-quality stereo material streamed from Qobuz via my MeLE Roon endpoint. The sound was clean with perhaps a tiny bit less “air” on the top end than I experienced from my 4x10HD. This difference was subtle, and discernible only at the upper limits of the audible frequency range with high sample rate source material. I expect that this small difference might be attributed to the 48kHz internal sampling frequency of the Flex HTx vs the higher 96kHz sampling rate of the 4x10HD. I reached out to miniDSP for comment, and the support team indicated that the 48kHz limit applied to both the Dirac and non-Dirac versions of the Flex HTx and that higher sampling rates would increase the cost of the Dirac Live license, which would drive up the overall cost of the product. Since an affordable price point is always an integral part of miniDSP’s formula, something had to give, and this was deemed a reasonable tradeoff. To make things interesting, the miniDSP dev team mentioned that feedback from users was considered, but that they did not make comments or commitments about future functionality. That means that this 48kHz limitation might be removed in the future, or not. Only miniDSP knows.

Give him the credit of seemingly attempted to ensure apples-to-apples comparison, but also seemingly didn't bother to do it blind, even the simpler just level matched single blind, yet he managed to notice that suble difference, did use the expression "might be attributed to the 48 kHz...., but then serious/sure enough to contact miniDSP support team. Presumably he would know that miniDSP is not going to say, you need to do it under DBT and the differences heard would disappear, as even honest engineers have to make a living by selling..

 

[peng]

Yep.
It's bizarre even to think about it, to output 4V of what? AC? At any freq above 20Hz-30Hz one would know REALLY well.
The hiss is probably at the uV range but I'm still surprised by it, minDSP is all about low noise and measurements (well, at least when they don't mess DSP) .

I think it would help us troubleshoot remotely if he can post a connection diagram from the source to the speakers and include the types/length of wires/cables. It is really an interesting case, to me anyway.

 

[rzrike]

Now I can understand why you might think that, but it is not possible! If you want to prove it, you just need a cheap multimeter and measure the output, if it does output 4 V even with no input connected you should contact miniDSP, they usually respond within 48 hours. Something else is causing the hiss you are hearing, wish I was there to troubleshoot it but..

Think about this another way, if it outputs 4 V all the time, how could you be hearing music, or even hiss, the SPL (sound pressure level) would have been dangerous high and damage your hearing already, when you connect the "4V" to your power amp and speakers.

I would suggest you take the time to find the real issue, there are simple enough steps that may take time, but you will be able to find the culprit.

That's why I started my comment saying I know the math nerds won't like what I am saying. I troubleshooted this for nearly six months last year. I tried different cables, different power outlets, power conditioners, etc, etc. Notably a very different sound from a ground loop. Had a call with Deer Creek where he got into the miniDSP Device Console remotely. Talked to VTV extensively. The only solution again and again was a voltage attenuator. I guess there's still the lingering possibility the HTx is just busted, but it sounds perfectly fine through RCA and through TRS with the voltage attenuators. It functions as expected in every other way. VTV believed the amps and the HTx are functional and up to spec and suggested the voltage attenuators (he has a bias toward believing the amps are functional since one of them was within his warranty period, but he obviously doesn't have a bias toward believing miniDSP's products are functioning).

Here was miniDSP's last email to me. Not sure where they got the idea I had a multiway setup. I was very clear in my communication. Their previous email was asking about a ground loop within the amplifier (I tried a shorting plug to confirm that was not the issue):

"In answer to your question, we unfortunately don't have that specific module and able to reproduce this issue but few things
- HTx is 4Vrms out. Your speaker supplier already suggested that with adding some pad correct? . For a tweeter that only need 1w to produce 86dB = very loud, you'd want to make sure that you pad that tweeter feed. That's how it's done on all/most of speakers (via passive xover OR in active via some smaller amps). You're more sensitive to it I guess for this setup
- Did you source these pads already? (not mentioned anymore after that). It's simple to do a passive attenuatione. The problem with that Hypex amp is that it has zero volume control. Max level all the times so not really fit for a direct drive in a multiway setup I'm afraid."

 

[rzrike]

I think it would help us troubleshoot remotely if he can post a connection diagram from the source to the speakers and include the types/length of wires/cables. It is really an interesting case, to me anyway.

The hiss existed (without attenuators) with just a simple connection from the HTx TRS-out to XLR-in of either of the Hypex amps to speaker wire to any of my speakers. No sources connected to the HTx (HTx only connected to power). The hiss was the same if I connected a source or if there was no source connected. I tried multiple brands of TRS-to-XLR cable (currently using Canare Star Quad). I tried multiple lengths. The HTx is close to the amp, so the cables are currently 3' I believe. The hiss was the same across different lengths of speaker cable (because the hiss was present on all of the speakers), shortest is about 4'. Some basic 14 AWG speaker wire from Amazon. I tried with my normal banana plugs and with raw wire.

 

[JohnnyNG]

Not crazy.
Bass performance is equated to 30% of speaker performance, EQ/DSP is mandatory to get a good bass result in virtually all rooms. ART is achieving results not previously possible even with 2.0, 2.1 or 2.2 systems. Maybe in time people will even add surrounds purely as support speakers, might even see specifically designed support surrounds for ART.

MiniDSP has the vision to tap into this. The Tide16 looks like a brilliant bit of kit

I run 2.1 but it's a 4-way active setup so this could fill multiple roles for me. The idea of "surrounds purely as support speakers" really sounds intriguing depending on placement requirements.

 

[peng]

That's why I started my comment saying I know the math nerds won't like what I am saying.

It is not a matter of like or won't like what you are saying at all, I, for one, just am very curious about your case of "hiss" and very interested in helping to solve the puzzle but obviously it is hard to do remotely. I have had a 2X4 HD, a HT and a HTx that I have been using with a buckeyamp that is also a Hypex NC502MP based and as i mentioned I never experienced any audible hiss, hence why I might be super interested in understanding your case issue.

I troubleshooted this for nearly six months last year. I tried different cables, different power outlets, power conditioners, etc, etc. Notably a very different sound from a ground loop. Had a call with Deer Creek where he got into the miniDSP Device Console remotely. Talked to VTV extensively. The only solution again and again was a voltage attenuator. I guess there's still the lingering possibility the HTx is just busted, but it sounds perfectly fine through RCA and through TRS with the voltage attenuators. It functions as expected in every other way. VTV believed the amps and the HTx are functional and up to spec and suggested the voltage attenuators (he has a bias toward believing the amps are functional since one of them was within his warranty period, but he obviously doesn't have a bias toward believing miniDSP's products are functioning).

I also have a VTV amp, a Purifi based one and have used it with the HTx too, no issue at all. I think Warren now has more understanding of "gain" and input sensitivity, but when I first dealt with him, I had to explain things to me and at time he still seemed stuck in his own understanding, though based on more recent posts on the topic ("gain") I believe he has the concept now. Still, if I were to get troubleshooting help outside of the amps he supplied, he might be the best person (a very helpful person though).

Here was miniDSP's last email to me. Not sure where they got the idea I had a multiway setup. I was very clear in my communication. Their previous email was asking about a ground loop within the amplifier (I tried a shorting plug to confirm that was not the issue):

"In answer to your question, we unfortunately don't have that specific module and able to reproduce this issue but few things
- HTx is 4Vrms out. Your speaker supplier already suggested that with adding some pad correct? . For a tweeter that only need 1w to produce 86dB = very loud, you'd want to make sure that you pad that tweeter feed. That's how it's done on all/most of speakers (via passive xover OR in active via some smaller amps). You're more sensitive to it I guess for this setup
- Did you source these pads already? (not mentioned anymore after that). It's simple to do a passive attenuatione. The problem with that Hypex amp is that it has zero volume control. Max level all the times so not really fit for a direct drive in a multiway setup I'm afraid."

That may be pointing to something, but as you alluded to, they might have the right picture of how your system is connected. So same to me, or may be others as well, that a more detailed interconnection diagram including the source, the HTx, the VTV amp, and any other amps in use, and the speakers will help.

But if for whatever reason, the attenuator is working well for you then I fully understand after trying to months, it may be time to just enjoy the music, though I hope you understand my point that, again it is not whether I like or don't like, it is just a fact that the HTx, if not defective in anyway, will not output 4 V, ac or dc all the time. That means the attenuator is working because it attenuate the signal that for some reason was too high, and yet without further information I have no idea why it would be too high, and for what, the power amp, or the tweeter that miniDSP seemed to refer to, may be may be not that they were actually onto something?

 

[peng]

The hiss existed (without attenuators) with just a simple connection from the HTx TRS-out to XLR-in of either of the Hypex amps to speaker wire to any of my speakers. No sources connected to the HTx (HTx only connected to power). The hiss was the same if I connected a source or if there was no source connected. I tried multiple brands of TRS-to-XLR cable (currently using Canare Star Quad). I tried multiple lengths. The HTx is close to the amp, so the cables are currently 3' I believe. The hiss was the same across different lengths of speaker cable (because the hiss was present on all of the speakers), shortest is about 4'. Some basic 14 AWG speaker wire from Amazon. I tried with my normal banana plugs and with raw wire.

Thank you for the addition info, but sorry, somehow I missed before I posted, so now have to rethink and repost, may be..

Edit: Just realized you posted your issues in the other thread so I think we can use that thread to avoid side tracking from the Tide 16 thread.

Hiss Issue with miniDSP HTx and Hypex Amps - Gain Mismatch or Defective Unit?

I’m troubleshooting a hiss issue and could use some insight. I replaced a Denon AVR with a miniDSP HTx (balanced outs) feeding two Hypex amps: a four-channel Hypex NC502MP and an NCx500OEM monoblock. Speakers are Philharmonic BMRs (86.5 dB), listening distance around 5-6 ft. I get a noticeable...

www.audiosciencereview.com

Let's go there before our moderator says something.

Before that, I also just realized you are getting hiss from the BMRs, are they bookshelf or tower? I also use my HTx, NC502MP with BMR bookshelf.

 

[Sokel]

The hiss existed (without attenuators) with just a simple connection from the HTx TRS-out to XLR-in of either of the Hypex amps to speaker wire to any of my speakers. No sources connected to the HTx (HTx only connected to power). The hiss was the same if I connected a source or if there was no source connected. I tried multiple brands of TRS-to-XLR cable (currently using Canare Star Quad). I tried multiple lengths. The HTx is close to the amp, so the cables are currently 3' I believe. The hiss was the same across different lengths of speaker cable (because the hiss was present on all of the speakers), shortest is about 4'. Some basic 14 AWG speaker wire from Amazon. I tried with my normal banana plugs and with raw wire.

How do you use it?
Dirac, filters loaded, correction full range maybe?

 

[Lsc]

You want to ruin these magnificent systems with some ARM variant chip and a $80 microphone?

I’m hoping the Tide16 will allow me to get rid my 2 channel preamp and dac. If the Tide16 can’t achieve that then I may as well get the AV20 and keep my 2 channel or just stick with my XMC2.

Do you think things will sound worse with the Tide16 and ART?