Noob question regarding latency

Optimize your system for ultimate performance.

Moderators: khz, MattKingUSA

mmcc
Posts: 3
Joined: Mon Mar 06, 2017 3:22 pm

Noob question regarding latency

Postby mmcc » Mon Mar 06, 2017 5:27 pm

Hi - I was playing around with KXStudio on an oldish laptop yesterday (running LUbuntu 16.10) for a pretty simple use. My kid has an electronic drum kit with a USB Midi output, and I want him to be able to use that with Hydrogen, and mix in an MP3 of whatever song he wants to play along with.

After much trial and error, I got it all working. I was able to use the GNome MP3 player, Hydrogen, NON Mixer and Catia so he can play along with songs, and make all the weird sounds that Hyrdogen is capable of. On to my question...

I have JACK configured for a sample rate of 48000 and a buffer size of 512, which gives me a latency of ~10ms. I get some xruns, but it doesn't seem like a huge number.

If I try a smaller buffer size, JACK won't start.

Is my inability to use a smaller buffer size a function of the crappy sound card in the laptop, or its crappy CPU?

varpa
Establlshed Member
Posts: 399
Joined: Fri Feb 25, 2011 6:40 pm

Re: Noob question regarding latency

Postby varpa » Tue Mar 07, 2017 4:10 am

Its most likely the crappy built-in sound card that prevents lower latencies.

mmcc
Posts: 3
Joined: Mon Mar 06, 2017 3:22 pm

Re: Noob question regarding latency

Postby mmcc » Tue Mar 07, 2017 2:39 pm

varpa wrote:Its most likely the crappy built-in sound card that prevents lower latencies.


Awesome. I've been poking around, and it looks like there are decent external audio interfaces for not a ton of money with mic, analog instrument and midi inputs. But, they seem to use standard midi connectors, and my (somewhat crappy?) drum kit and keyboard only sport usb outputs for midi.

So... are there external audio interfaces that have usb ports for midi input? Or can midi from the PC's USB ports be used by external audio interfaces that support midi? Or should I take this question to a different forum?

Gps
Establlshed Member
Posts: 40
Joined: Mon Mar 09, 2015 3:09 pm

Re: Noob question regarding latency

Postby Gps » Tue Mar 07, 2017 11:53 pm


AyeLinux
Establlshed Member
Posts: 10
Joined: Fri Jul 31, 2015 8:27 pm
Location: California, US

Re: Noob question regarding latency

Postby AyeLinux » Wed Mar 08, 2017 3:38 am

You don't need to run all your MIDI through the interface. You can plug the USB instruments directly into the computer. Then you can use qjackctl (or whatever you're using to configure JACK) to route the MIDI signals.

If you're low on USB ports, you can use a hub for the MIDI instruments. Just avoid hubs for the audio interface.

If you can't figure out the details, just ask. Someone here will point you in the right direction.
All in favor of Linux, say 'aye.'

User avatar
SLCBagpiper
Establlshed Member
Posts: 12
Joined: Mon Jul 13, 2015 3:07 am
Location: Salt Lake City, UT
Contact:

Re: Noob question regarding latency

Postby SLCBagpiper » Thu Apr 20, 2017 3:20 am

If you're low on USB ports, you can use a hub for the MIDI instruments. Just avoid hubs for the audio interface.


I'm very glad you brought that up. Given that there's very low voltage in a USB circuit and, by extension, in each USB port in a hub, you couldn't expect to run a USB-connected condenser mic by plugging the mic directly into a USB hub; you wouldn't get enough volume.

But would it be possible, do you know, to get that same USB-connected condenser mic to produce acceptable volume when plugged into a USB hub IF there were an intervening mixer board with phantom power?

In other words, if we plug the USB-mic into a mixer board with phantom power---probably after first using a USB-to-RTS adapter, or maybe a USB-to-XLR adapter---then out from the mixer board's USB connection, and into the USB hub, and from the USB hub into the computer running the DAW, etc., do you know if that sort of a set-up would work? Or is that just too crazy, even if we have all the hardware & adapters & such?

Thanks in advance for your kind help. All The Best! Slàinte!
"If it's stupid, but it works, then it's not stupid."
---Art. III, Murphy's Military Law


Return to “System Tuning and Configuration”

Who is online

Users browsing this forum: No registered users and 3 guests