Transferring my LP's but Audacity slo-mo's the music!

[rycher10]

I'm having a hard time figureing this one out. I am in the process of beginning to transfer all my LP's over to my media library. I have a few different software packages to help me import, clean, restore, and catalog my transfers - Audacity for importing, isotope RX2 advanced for restoration, and a few others. My equipment is as follows: Acer dual-core Intel laptop with 4 gigs ram and running Windows 7 32 bit, Tascam US-144 mkII, Denon DP-62L turntable with a Denon DL-160 moving coil cartridge, Cambridge Audio 640p phono preamp, and high quality interconnects. My goal is to transfer to my PC my LP captures using Audacity in 24/96 wav. Then using isotope RX2 I will remove any ticks, pops, noise, and what have yous. Then save my file to 24/96 FLAC, seperate songs, and add all relevant Meta tagging info. ........this is the plan

I can capture my lp's just fine, as well as save them in Audacity in wav. I can monitor the capture thru my headphones as it's recording, and I can see the work space graphs doing their thing. Now, if I attempt to import those saved captures they play back in slow motion.....approximately 2.5 times slower! Even if I open those files in other programs like isotope and MediaMonkey they still play back in slow motion. I've gone so far as to delete those captures and start the process all over again. I take care to set all levels carefully and approprietly, and I am NOT intentionally applying any speed changes. I don't know why Audacity is doing this. I can, however, use the speed adjustment setting and speed up the music until I *think* it's correct, but it still won't save it at that speed....it stays in slow motion.

Does anyone know what is going on here? Is it something that I am doing wrong? So far I have made 5 attempts at capturing my LP's, and although they capture just fine, it's when I save them that they get saved in slow motion.

Thanks in advance.

Jimmy

[kozikowski]

It may be as simple as Windows doesn't support 24-bit. I'm looking for notes we made on this.

There is one note of interest. We only get complaints from people using top end equipment trying to do advanced bit-rate captures and production. The people doing plain vanilla processing sail right through. There is a spirited discussion of USB problems with higher bitrates.

Koz

[kozikowski]

Here's a note from another web site.

I do a bit of recording and usually bounce my tracks to 16bit WAVs because Windows Media Player doesn't support 24bit WAV out of the box and I couldn't find the right codecs.

Koz

[PGA]

What have you got set as Audacity's Project Sample rate (bottom left corner of the Audacity window). If you want your workflow to be 96KHz throughout, I think you need to ensure this is set to 96000 BEFORE you record or import anything.

[rycher10]

I do have Audacity set for 24 bit and 96k as default even before anything is imported.

As for Windows not supporting 24 bit. I don't know what you mean here. I have around 500 gigs of 24/96 and 24/192 FLAC music files from HD tracks, and I play them back in both MediaMonkey and J. River MC with no issues. I do not use Windows Media Center for anything. Maybe you mean that Audacity installed in Windows does not support 24 bit importing into it? I don't know. I have read in other forums that many Windows users are running Audacity just fine.

Do you think it can be a Windows issue? Or an Audacity issue? I would love to get this speed issue resolved.

Thanks.

[steve]

Windows does support 24 bit audio in that 24 bit audio can be played, edited, copied,....
When Audacity records, it sends a request to the OS sound system for the type of data that it wants. If Audacity is set to record 32-bit float (default) then Audacity requests 32-bit float format audio data. The request is passed to the Windows sound card drivers via Portaudio which is an open source, cross-platform audio I/O library. If the sound card drivers are unable to provide data in the requested format (perhaps because the sound card hardware does not support that format), then Portaudio negotiates with the sound card driver for the closest format to it. If the supplied data is in a lower bit format than what has been requested (always the case when Audacity is set to record 32-bit float) then the audio data is converted from the actual supplied data format to the requested format.

The conversion from a lower bit format to a higher bit format is lossless and very fast as, basically what it is doing, is sending the supplied data, with the "unused" extra bits set at zero. 32 bit float format is generally recommended as the recording format as it has several benefits over integer formats.
Computers can usually handle 32-bit float data faster and more efficiently than integer formats.
32-bit float format also offers much greater precision when processing.
Audacity works internally with 32-bit float format, so there is no format conversion required while processing.
32-bit float format can handle a much greater dynamic range than integer formats (over 1000 dB). Although this does not benefit the dynamic range of the recording, it avoids creating extra noise or clipping during processing.

On to your question - why the speed changes.
From reading through this topic, you're probably not doing anything "wrong" rycher10, but nevertheless there is a problem.
I think that the first thing that we need to do is to get a base-line recording to see if we can get this working in any shape or form. If we succeed with that then we can try to improve on it.

What I'd like you to try is setting Audacity to its default settings of 32-bit float, 44100 Hz as the default format. Set this in the Audacity preferences, then close Audacity.
(to change those settings: "Edit menu > Preferences > Quality")
Then go into the Windows sounds control panel and set the recording format for your sound card at 16 bit 44100 Hz
(there's some information about accessing those setting here: http://wiki.audacityteam.org/wiki/Mixer ... es#vistacp)

Open Audacity and make a test recording.
Play the recording back in Audacity.
Export as 16 bit WAV.
Play the exported WAV file in your usual media player.

What happened? Did that all work correctly?

[otwo_pipes]

Been there done that myself
My error was not have consistency throughout. My situation is a little more complicated because I am using an external ADC. I quickly resolved my error and as it was ages ago my memory is a little hazy but I believe I set the capture rate in preferences to 96kHz and maybe I changed the setting on the project sample rate as per:-
@PGA

What have you got set as Audacity's Project Sample rate (bottom left corner of the Audacity window).

My problem which was exactly as you described was due to Audacity setting not being consistent throughout.
I hope this helps.
p.s. I learnt to set the quality in preferences and never to touch the Project Sample Rate, only to check the PSR was as per the settings in Edit/Preferences/Quality

[otwo_pipes]

@Rycher:

...isotope RX2 advanced for restoration

I am undertaking exactly the same task as you and I have around 800 LP's to import (about 300 completed). I have looked at restoration sw and Isotope RX2 is high on my list. Do you have any useful feedback on Isotope RX2 you could pass on to myself and others?

@Koz:

There is a spirited discussion of USB problems with higher bitrates.

Could you please provide a link to the 'Spirited' discussion and thanks in anticipation.

@Steve:

Windows does support 24 bit audio in that 24 bit audio can be played, edited, copied,....
When Audacity records, it sends a request to the OS sound system for the type of data that it wants. If Audacity is set to record 32-bit float (default) then Audacity requests 32-bit float format audio data. The request is passed to the Windows sound card drivers via Portaudio which is an open source, cross-platform audio I/O library. If the sound card drivers are unable to provide data in the requested format (perhaps because the sound card hardware does not support that format), then Portaudio negotiates with the sound card driver for the closest format to it. If the supplied data is in a lower bit format than what has been requested (always the case when Audacity is set to record 32-bit float) then the audio data is converted from the actual supplied data format to the requested format.

I believe the above implies that if the sound card supports 24 or 32 bit recording Portaudio will transfer the data, in the requested format, to Audacity. However, in post http://forum.audacityteam.org/viewtopic ... 46&t=66697 you stated:-

...there is no benefit to recording in 24 bit with any release build of Audacity on Windows because PortAudio (the library that acts as an intermediary between Audacity and the computer sound system) only passes 16 bit data to Audacity - the last 8 bits of 24 bit audio are replaced with padding (8 zeros if I remember correctly).

I think your post in the first paragraph states Audacity and Portaudio will handle 24 or32 bit data, dependant on the sound card, and your post in the second paragraph states only 16 bit data is transferred to Audacity by Portaudio. Could you please enlighten me as you seem to be telling Rycher he can record in 24/96 and the opposite to me?

I also asked in post http://forum.audacityteam.org/viewtopic ... 7&start=20

Does the 16 bit PortAudio limitation apply when the ADC is an external box, as in my case? I am not, as far as I am aware, using the computer sound system because the external ADC interfaces to Audacity via S/PDIF. Audacity sees the M-Audio driver interface because I can select the S/PDIF input.

Maybe you did not see my post but I have not yet received a reply.

[steve]

Maybe you did not see my post but I have not yet received a reply.

No, sorry I missed that one. I've now posted a reply.

Portaudio should be able to "handle" any valid bit format that you throw at it, but the bit format that is sent from Portaudio to Audacity is not necessarily the same as the bit format that is sent from the sound card to Portaudio. Handling of 24 bit data by Audacity/Portaudio is discussed in length elsewhere in the forum, but I think the priority now in this topic is to try and resolve rycher10's "slow playback" problem.

[PGA]

...I think the priority now in this topic is to try and resolve rycher10's "slow playback" problem.

Sanity check: Is the Transcription Toolbar slider set at 1.00x ? Let's eliminate the trivially obvious before delving deep into the innards, eh?