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1
This closely resembles the classic Radio Shack SPL meter used by many do-it-yourself home audio calibrators (including yours truly)

http://www.cnaweb.com/analog-sound-level-meter.aspx

It's $40 bucks.
2
Well, it was indeed sold as a set (DVD player + speakers).
If I'm getting you correctly, is it enough to set the speaker volumes to the default zero?

I don't have any control over the frequency response anyway so I guess I might just try to run Adobe Audition, analyze the audio that my external mic receives, and try to set the volumes so that they have the same LUFS loudness.

Thanks for the answers! I really appreciate it.
3
3rd Party Plugins - (fb2k) / Re: foo_random_pools
Last post by stevehero -
Amazing. I commend you on this plug! Thank you!
iTunes is starting to feel like that old girlfriend that seemed so nice at the time :o

Anyway, just wanted to ask if it's possible for each pool to be assigned its own playlist to auto-add to.

See screenshot for better understanding. Forgive me if this has been suggested before.
4
I'm looking for a codec that's suitable to compress the audio of old computer tapes.

Took me a couple tries understand what you need, but the nail finally dropped: you mean something like the audio from Datasette tapes, like for a C64 and a PET, correct?

If that's the case, I remember a dude at some Demo party had a similar system. In case it's the Datasette it's a little tricky because it doesn't use sines for '0' and '1', instead it writes square waves directly onto the tape. He used some sort of App on his phone to generate the files on the fly. I.e. the files were in binary form, and the App would generate the tones and output them through the headphone jack.

Another dude I know keeps the files as MP3s, because the SNR of those tapes wasn't exactly superb to begin with. Especially the tape machines were kinda low-range, etc. He just plays them back on his phone and it works every time. Even with C64 "Turbo Tapes".

So for archival reasons, having binary versions of the information is probably the best way to go, for quick playback from a phone, just go with the most convenient audio format.

EDIT: Just in case anyone cares, the binary files were tiny, even though they were uncompressed. A couple kilobytes at most. I'm guessing that if you'd use anything else but a stream compressor like xz or lz77, you'd get so much overhead it wouldn't even be worth doing.
5
Imgur is fast enough for now, although it does have a time expiry for anonymous uploads if they're not accessed for several months. I'm not sure if the same applies to authenticated uploads, as I have some uploads that I don't think have been accessed for years, rather than just months.
7
This is for Commodore 64, I'm using a 90s cassette-to-line-in-adapter in the tape player, and it works really well.

And 622kB instead of 1705kB (A tape turbo) is of course no big deal. But it somehow hurts deep inside when I know 7z makes it 5kB. :D

I found this: http://www.foobar2000.org/components/view/foo_unpack_7z

... but alas, foobar mobile don't seem to have support for add-ons.
8
Audio Hardware / Re: Interview Time
Last post by Arnold B. Krueger -
"Any legacy SS amp that has a single power supply for its output stage generally has a large DC blocking capacitor that will interact with some woofers to create relatively large amounts of bass boost (YES, BOOST!)  - often several DB in the lowest normal octave."

What is a "legacy SS amp"? How far back are you going in time? 10 years? 20 years? More?


I'm talking second generation SS amps - late 60s, early 70s.

Notable because they use silicon output devices (not germanium types like the first generation), typically no coupling transformers, single-ended power supplies, output coupling caps.  Lots of Japanese receivers and amps, as well as the Dyna 80 and 120, the Heath AR 15, AR amplifier, etc. The AR amp was a bit of a throwback as it had a driver transformer. Mostly topped out at 50-60 wpc.  The next generation included the early Phase Linears, Crown DC 75 and 300, Dyna 400,  etc - notable because they had split power supplies, no output coupling caps, more power 150-200 wpc, but still had SOA problems.
9
Your best bet is to research a way to store the demodulated data into a player that will remodulate it back and output the signal. There are some mobile apps that do that but I don't remember their names etc. They store the actual data carried on the audio part but they are saved as data and not audio, which should be some KB of data and upon demand they will modulate the file and play it back from their headphone jack. If I'm not wrong asciiexpress.net online portal actually works that way.

I could help more if I knew exactly for what system you try to achieve this.
10
Most audio tape-based computer data formats (record and play on standard audio tape deck) are designed to work with limited frequency response and low SNR, speed variations, and phase shifts. They typically only need telephone grade bandwidth and SNR (4 KHz bandwidth, 40-55 dB SNR). You could use a lower sample rate such as 11 or 8 KHz / 8 bit.
Do consider the playback mechanism, though. It's no use using 8/8 format, or some specialised codec format, if the playback device doesn't support it.
Personally, I'd use MP3 encoding.  About 10 years ago I had to record the training sequence and data stream of a 2400 bps modem and send it to an overseas lab. I recorded it at 16/44.1 mono and converted to 128 Kbps MP3. The lab had no difficulty playing it into their analyser. I just now took one of the original files and compressed it with LAME at quality 9 (VBR, 45-85 Kbps) for a 20:1 reduction.  Overlaying the input and output waveforms shows an almost perfect match.