Onboard HDMI vs Audio Interface

[MelloProg]

When producing music with Logic Pro on a Mac Pro (2013) one might think that no further audio interface is needed (assuming that no audio recording is involved). I can use the digital audio out or HDMI which theoretically should give me even the option of 5.1 channels. And it does works of course, but...

I did this (HDMI) and encountered lots of issues, e.g. crackles and pops even though I have enough CPU headroom, enough RAM samples streaming from SSDs.

Then recently, I re-instated my old MOTU firewire Ultralite audio interface and the crackles and pops were gone.

This may sound like an odd question, but is there are correlation between a possibly bad audio stream on HDMI and the audio via the audio interface in relation to Logic Pro? I'd have to note that if I "just" play music from a regular audio player the HDMI connection sounds fine and it also handles 5.1 perfectly.

It would be great if someone could shed some light on this scenario.

[chk071]

You don't mention at all what exactly you have connected to your Mac Pro. I'm not aware that many studio monitors have a HDMI input...

[MelloProg]

I have a high quality processor and Amp connected, they would not pose any obstacle of any sort.

[T-CM11]

I have a high quality processor and Amp connected, they would not pose any obstacle of any sort.

Did you copy that from the brochure? Maybe you should upgrade to the Ultra High Quality Mega Processor Amp?

[lfm]

I think this is due to not syncing input audio and output device on the driver/protocol ASIO, Core Audio or whatever you use.

Some daws have setting which audio stream to sync to for input and output. when having multiple digital devices in studio wordclock seems to be what most devices support. So all input and output streams are synced this way.

I don't know anything about Mac, but on Windows WDM drivers allow multiple devices. ASIO does not allow multiple devices in general. But sticking to RME, their drivers handle any other RME device if having many.

Overall I don't think HD Audio over HDMI is at all made for producing music. Latency might be high and only intended for playback. Audio for film basically.

So if having an input stream not synced to that it may produce crackles and pops - if recording or monitoring through daw.

So a single device for input and output is probably the simples way to remedy such problems.

[MelloProg]

I think here we are getting a bit closer, raising concerns about the syncing - however, just to clarify, I have no external audio streams going "in" - everything is sound libraries (VE-Pro, 99% Kontakt) or are you talking about a different kind of input when mentioning core audio, some some internal process?

[fmr]

If you have a MOTU, why would you use the HDMI for audio? maybe a silly question, but you should use things for what they were intended. As said, HDMI was thought for maybe a stream of recorded video AND stereo or surround audio, not the kind of tasks a multitrack DAW is designed for (especially when that means audio produced in real-time by virtual instruments).

It always amazes me why people spend lots of money on a system, and then try to save on the details. As it's usually said: "devil is on the details". Do yourself a favor: Use the MOTU and forget that HDMI thing. It wasn't thought for the task you are wanting to use it for.

[ghettosynth]

When producing music with Logic Pro on a Mac Pro (2013) one might think that no further audio interface is needed (assuming that no audio recording is involved). I can use the digital audio out or HDMI which theoretically should give me even the option of 5.1 channels. And it does works of course, but...

I did this (HDMI) and encountered lots of issues, e.g. crackles and pops even though I have enough CPU headroom, enough RAM samples streaming from SSDs.

Then recently, I re-instated my old MOTU firewire Ultralite audio interface and the crackles and pops were gone.

This may sound like an odd question, but is there are correlation between a possibly bad audio stream on HDMI and the audio via the audio interface in relation to Logic Pro? I'd have to note that if I "just" play music from a regular audio player the HDMI connection sounds fine and it also handles 5.1 perfectly.

It would be great if someone could shed some light on this scenario.

You say no recording, but, do you also mean no recording of midi where you are trying to play instruments in real time? I don't know of anything intrinsic about HDMI that will cause you any issues for just monitoring. I regularly use HDMI as an output for listening to mixes on my home theater system which has proper monitors on the front channel and there is no problem other than very high latency. Even though I have a mac with HDMI, I can't recall trying to adjust latency and I'd have to go look to see if it's possible to force it to be too low.

So, for just monitoring/mixing/mastering, HDMI is just fine assuming that you know what's in the chain with respect to processing and are taking that into account. For example, my receiver has some magic EQ bullshit that I have to turn off and even without HDMI, latency from analog input to speaker output is too high for DJing. This means that even in that chain there is some digital processing of the signal that is causing latency.

[jancivil]

I think here we are getting a bit closer, raising concerns about the syncing...

Syncing what? It looks like you are comparing using something designed for getting your audio out to surround in some form of HDMI-compliant box for home entertainment vs working in the box in Logic.

For the latter, you found that your MOTU interface worked better. That's about the size of it (additional latency by using HDMI shouldn't affect the performance of your computer).

"word clock" is for something else, such as getting data (from, say, Logic) out to a hardware device in perfect sync: it's used to ensure an exactly timed and constant bitrate to avoid [data] errors. The only scenario I expect this to apply here is if you are converting sample rate for the secondary device.

The lack of such should not through itself be causing poorer performance of Logic. The performance is in all likelihood improved by the MOTU audio interface vs the motherboard's sound chip.

[ghettosynth]

The performance is in all likelihood improved by the MOTU audio interface vs the motherboard's sound chip.

There is no "sound chip" on the motherboard with respect to HDMI. Whatever D/A is being used exists in the device at the other end of the HDMI cable.

[jancivil]

Reading is fundamental.

"vs" (IE: versus; as opposed to; in contrast to) the motherboard's sound 'card'. Realitek chipset or what-have-you.

[jancivil]

I actually think it's possible in some scenarios where competing for master clock status with multiple devices could produce 'pops and clicks', which is something I took as specific to say my own process using soft instruments in the box.

IE: "If you have digital connections in your studio (S/PDif, lightpipe, etc), you MUST have a single clock source. If multiple devices are each trying to be the master clock, you will probably experience pops, clicks, or sometimes chirps in your audio." from a Sweetwater blog page I was looking at for something else 'sync' couple days ago.

[ghettosynth]

Reading is fundamental.

"vs" (IE: versus as opposed to; in contrast to) the motherboard's sound 'card'. Realitek chipset or what-have-you.

OP is comparing HDMI to MOTU, where exactly do you think something like a Realtek chipset is involved? Again, there is no "soundchip" on the motherboard that is involved with audio over HDMI.

Audio over HDMI uses the same digital transmission channels that video uses. The GRAPHICS card takes the DIGITAL audio stream, e.g., samples, and interleaves it with the video stream. What exactly do you think this process does to the sound? Take a look at your HDMI connection when connected and note that the audio output device specified is actually the endpoint of the HDMI connection. On this machine, for example, it is the TV that I use as a monitor.

The "sound" of something like a Realtek driver is a function of the quality of the D/A converters being used. Again, I will repeat for you, the D/A converter being used with HDMI is in the endpoint, e.g., the TV set or receiver. Yes, the quality of that D/A matters, but it has NOTHING to do with the motherboard audio chipset.

Today you learned something.

[jancivil]

HDMI is a type of cable. Taking audio data out to an HDMI-compliant device.
The computer's "sound chip", vs. what again? Yeah, I'm ignorant, I don't know why the computer would have a special chip for an HDMI cable. I was talking about performance, vis a vis 'pops and clicks' and as I did I opined I didn't think the cable should affect that. So there is a context to remarks, which one can think on for a second, or_not.

"The performance is in all likelihood improved by the MOTU audio interface vs the motherboard's sound chip."
Most everybody would seem to understand that sentence here, or so I would think. Use an audio interface's drivers rather than the onboard 'soundcard', same as it ever was.

[ghettosynth]

HDMI is a type of cable. Taking audio data out to an HDMI-compliant device.

Um no, HDMI is a specification for digital audio that includes far more than the "type of cable." Do you use HDMI for production audio?

The computer's "sound chip", vs. what again? Yeah, I'm ignorant, I don't know why the computer would have a special chip for an HDMI cable.

Well, now you do. Well, sort of, really, there's no "special chip" so much as there is no chip at all until the data has to be transferred or played. Digital audio, like video, is just a stream of numbers so until it gets converted to analog there is seldom a need for a "chipset." That said, modern soundsets do more than just convert digital to analog, but that's outside of this conversation. Whatever those features might be are handled by the HDMI endpoint. The Graphics hardware is what handles this stream of data when using the HDMI connection.

"The performance is in all likelihood improved by the MOTU audio interface vs the motherboard's sound chip."
Most everybody would seem to understand that sentence here, or so I would think. Use an audio interface's drivers rather than the onboard 'soundcard', same as it ever was.

I think that most people who were trying to answer a technical question clearly would say driver if they mean driver. But you're taking this too personally. I simply corrected your misstatement to avoid further confusion.