Audio drop-out at beginning of cut!? (Audio Included)

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Fattcamp
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Audio drop-out at beginning of cut!? (Audio Included)

Post: # 67363Unread post Fattcamp
Mon May 05, 2025 4:12 pm

Hey guys,

I've been playing around with Dave's Lockdown Lathe build for awhile now and love the thing. One issue I'm running into with my current client is the audio drops out for a split second at the beginning of the first track and resumes as normal after. The intro song features bagpipes which have their intense frequencies. When previewing the prepped audio files in the Vinyl Burn software, you can re-create the dip every other try or so.

- I know it's not the Vinyl Burn software itself because I can preview the song through speakers/headphones and can't recreate the issue.
- I've tried a second amp and the same issue occurs when previewing the song before cutting regardless of level I'm sending to the cutterhead.
- The first amp is one I've been using all along. It's an ART SLA2 amp with 200-watts/side @ 8 Ohms. The second amp is a Matrix GT1000FX providing 300-watts/side @ 8 ohms.
- It probably doesn't matter but I'm running 500ma fast blow fuses in-line form the amp to the cutterhead.
- I'm using the recommended Tectonic TEAX-19C01-8 coin exciters for drivers on the cutterhead
- I do have extreme EQ applied to the prepped files after calibrating using the method provided by spinnertownblanks (https://www.lathetrolls.com/viewtopic.php?f=1&t=10321[/list]

I'm wondering if I need even more power due to the intense EQ applied or if I need to dial back the EQ regardless of amp. All I know is that I've cut a bunch of records. Folks are happy with the medium fidelity mono cuts and this only pops up now and then. I'd love to hear your thoughts as the second I start cutting this record, the blank is ruined.... or at least has a 50/50 chance of being ruined. Could speaker wire guage be a part of it? I know the guage is much thinner than the amps would normally use but they are connecting to tiny drivers, and that seems to be the norm. File attached for context.

Audio Issue.mp3

Thanks,
Dave
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Fattcamp
Posts: 68
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Re: Audio drop-out at beginning of cut!? (Audio Included)

Post: # 67365Unread post Fattcamp
Mon May 05, 2025 4:25 pm

Holy moly... of course after posting this, I discovered something:

Before when I was testing through speakers/headphones, it wasn't happening but that was using a different interface running on my mac. I'm using a virtual machine on the same mac to run windows/Vinyl Burn with it's own dedicated audio interface. When I plugged headphones into the interface feeding the amp, I was able to recreate... so it's happening entirely prior to audio hitting the amp. I think I'll either try another interface, try a vm on my laptop or a combo of the two. It's a bit of a franken-setup but doesn't appear to be the fault of the amp/cutterhead/frequencies of the prepped tracks.

Dave

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markrob
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Re: Audio drop-out at beginning of cut!? (Audio Included)

Post: # 67366Unread post markrob
Mon May 05, 2025 4:30 pm

Hi Dave,

That's weird. Do either of the amps have clip indicators? If so, do you see them flash at the time of the dropout? If you connect a standard speaker in place of the head, do you get the same dropout? If you are running a PC, have you set your audio buffers to a high value (e.g. 512 or even 1024)? Maybe a random system dropout due to some background process running. For that to happen, both channels need to dropout. Seems unlikely other than a software issue. I wouldn't think most modern amps would not dropout if overdriven. They normally would limit or clip the output. In the example, I didn't hear a sharp transient that might trigger an event.

Mark

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Fattcamp
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Re: Audio drop-out at beginning of cut!? (Audio Included)

Post: # 67370Unread post Fattcamp
Mon May 05, 2025 5:29 pm

Hey Mark,

Thanks for the quick response. I didn't see them flash at the time of the dropout but it appears to be happening before cutting when previewing the prepped tracks with the headphone out of the interface. I'm going to try a PC laptop with the same interface and see if it still happens. If it does, I'll try a different interface. If it doesn't occur, then it's something involving my windows VM running on my mac with a dedicated interface... or something along those lines.

Dave

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markrob
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Re: Audio drop-out at beginning of cut!? (Audio Included)

Post: # 67371Unread post markrob
Mon May 05, 2025 5:37 pm

Hi,

If you run on a PC, try to use ASIO drivers if your interface supports them. Most do today. Set the ASIO buffers to a higher (e.g. 1024) value since you are not trying to do real time monitoring like you would if playing a VST instrument. The latency does not matter in your application and higher buffer sizes puts less load on the CPU. Run at 44.1 or 48Khz as higher rates put more load on the CPU.

Mark

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