i2m device vs g2m app latency

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i2m device vs g2m app latency

Postby Stujar » Tue Jan 14, 2014 12:15 am

Hi

I want to record using iPad Garageband, and specifically, I want to use a guitar to record bass - I've tried the midimorphosis app and it's been disappointing - mainly the latency but also rogue notes and their documentation have led me to give up.

I was thinking I'd better just get a real bass, then I saw your i2m device and wondered if it would be better latency-wise...

But then I see you (seems to me) pushing your g2m app, and not really pushing the i2m device in the last year (no entries on your forums, no hype)- so can I ask, how do the i2m device and the g2m app compare latency-wise - do you have a like-for-like video / some way to see the relative merits of the two?

Thanks in advance

Stujar
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Re: i2m device vs g2m app latency

Postby james » Tue Jan 14, 2014 9:56 am

The latency on the i2M is lower than the G2M app. (Note that the G2M hardware product has similar performance to the i2M). I think the difference is around 6ms, at the G2M app's lowest latency settings. This is to do with internal audio buffering in iOS.

The other difference is that i2M has lots of MIDI configuration options, much more than the G2M app. You need to configure it with a PC/Mac though, because the editor is not supported in iOS. Once configured, you can save 4 presets and select these using the button on the i2M, so once configured, you can use these presets on iOS. See this link for more info on the editor to get an idea of what's available:

http://www.sonuus.com/products_i2m_mp_editor.html

We don't have a video that shows a direct comparison between the two. The latency of both products is very low, and the difference between them is small, so I don't think you'd be able to see much in a video. You really have to play them to feel the difference.

How are you connecting your guitar to your iPad? You get best results if you use a proper guitar interface that connects to the dock connector. An good adapter that connects to the mic input will work pretty good for guitar, but the lowest notes may have a few issues because the microphone input has a high-pass filter in it which cuts the level of these low notes. Avoiding the lowest octave of a guitar will avoid this.

A dock-connected interface, however, doesn't have these limitations. The i2M will work connected to the dock using the "Camera Connection Kit", not only for MIDI but as a high-quality audio interface too.
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Re: i2m device vs g2m app latency

Postby Stujar » Thu Jan 16, 2014 1:06 am

Thanks James and sorry to pester but...

you mentioned 6ms difference between the app (with a good audio interface) and the i2M - I'm not a good judge of ms so would be useful to know what the actual minimum latency of either of them is and/or the % difference

I use an Apogee Jam at the moment and found the midimorphosis unusable with it - is the app much better? I'm loathe to spend more on the app if I actually need the i2m device.

Then again I'm worried the i2m device might prove unusable too (for playing bass via guitar in ipad garageband)

You said in passing that, "You really have to play them ..." - I think you're right. Is there anywhere near London that sells this stuff in a shop where I could turn up with my ipad and try them out?

Or is there a video that shows the limitations?

...if I can play bass triplets at 120bpm I'll be happy

Cheers - thanks for your help

Stu
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Re: i2m device vs g2m app latency

Postby james » Thu Jan 16, 2014 9:58 am

Hi Stu,

The specs for the i2M are here, and it mentions latency: http://www.sonuus.com/products_i2m_mp_spec.html

The latency depends on the note being measured -- it's not possible to measure it before the string has completed one vibration cycle. In summary, the latency of the i2M is: 5 ms (E5), 17 ms (E2), 32ms (E1), 40 ms (B0)

So, for guitar, it's typically 17ms or faster. For most notes, this is maybe 5-10ms. So, the additional 6ms is quite significant in this case, but it is small enough to adapt to quickly (speed travels approximately 1 foot per ms, so 6ms is like sitting 6 feet from your amp).

However, other MIDI converters will usually have latency of 40-100ms -- at these levels, only playing slowly is possible.


I don't know for sure which stores in London have the i2M. DV247 have it listed, but you need to phone their store to check if its in store.

http://www.dv247.com/computer-hardware/ ... ace--81068


You can also get it directly from us. Any problems, and you can return it within 14 days. This link also has a video showing some playing with the i2M -- there is no video trickery going on, what you see is the real latency.

http://shop.sonuus.com/product_info.php?products_id=33

Another advantage of the i2M is that you can transpose the MIDI notes by a large amount -- useful if your program doesn't let you do this. You you can play your guitar in the higher registers for lowest latency and output low bass MIDI notes. 120bpm triplets are not a problem -- it only becomes difficult trying to do this on the lowest strings (physics gets in the way!).
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Re: i2m device vs g2m app latency

Postby braguesa » Mon Apr 07, 2014 4:09 pm

Hi!
Check this little video I made with I2M interface and G2m app, simultaneously:
https://www.youtube.com/watch?v=vnsijtDksXg
I managed to reduce G2m to 128 samples with audiobus 2.
I'm using a flute sample the G2m on normal octave and I2M an octave lower.
I feel exactly the same latency with I2M and G2m with this settings.
Hope this will help.
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Re: i2m device vs g2m app latency

Postby james » Mon Apr 07, 2014 4:16 pm

Very nice, thanks for sharing.

The few ms difference between the i2M and G2M app will generally not be noticeable if everything else is setup well. Usually, extra latency from the audio system buffer size when using soft synths will be the main difference.
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