Lots of audio calibration MP3's available

I ripped and encoded a CD called Sound Check from the Alan Parsons Project. It's called a "Professional Audio Test Disc" and it's got lots of test tones and other tracks to help in calibrating a sound system. It's the best CD I know of for this purpose. I used it along with a Radio Shack ("You've got questions. We've got blank stares.") SPL meter to help me set my EQ. I'm extremely pleased with the results. If you do use the Radio Shack SPL be aware that it's readings below 100 Hz are pretty inaccurate. Actually, none of it's readings can be considered highly accurate but it's OK for $25.

Since this disc is no longer in print (Mobile Fidelity rest in peace) I don't have a problem with offering it to share. I've got the original WAV's and MP3's encoded at 320K using LAME.

Send an email to audiotest@theginsburgs.org for ftp instructions. That's an autoresponding address so I won't see anything you write.

Please heed the warning in the email about track 59.

-Dylan

You know, this is beginning to sound like the X-files here. I was just going to ask if anybody had something like this and the next post I read ...

Man, this is just ... too creepy

Dylan, thanks, going to get them rightaway. If only just to test that dolby surround amp at home *cough*

Cheers,
Hans


Mk2 - Blue - 080000431

For reasons I can't figure out, my email server has problems sending mail to some domains. If you don't get an autoresponse within a few minutes then send me mail at empeg@theginsburgs.org. (That's not an autoresponder.)

-Dylan

I am sure the god knows how many people constantly trying to leech those files of your machine (is it the same machine ?) does not help .

On the other hand I have noticed that far too many times a lot of sites work with out-dated DNS records. Either that or KPN Holland is screwing up our DNS registrations. Come to think of it ... they probably are.

Cheers,
Hans


Mk2 - Blue - 080000431

As far as too many people, hopefully everyone is only downloading ONE file at a time, so they don't hog the bandwidth. I'm sure those with modems are downloading only one, but people with broadband tend to be abusers. I've got DSL, but I'll only download one file at a time from a server, unless I know it can handle it. I'm currently getting about 6-10k/sec. from his server. So, be kind folks!

George

I set my GetRight to 1 file at a time max so ... Yes, about 10 K too but I am on dual-ISDN (i.e. 128K)

Cheers,
Hans


Mk2 - Blue - 080000431

Hmm, I am starting to wonder if perhaps this is not something the Empeg people or one of us should build something for. IE, something that directly controls the DSP to do such things (the music and normal soundbits excluded). Just to be sure of the accuracy of the reference tones ...

Cheers,
Hans


Mk2 - Blue - 080000431

You people have been busy.

I've only got 40KB upstream with my DSL account. I limited my FTP server to only 5 logins figuring that it's better to give a small number of people reasonable bandwidth instead of letting everyone on and having no one get decent throughput. But it would help if someone else can mirror this stuff.

-Dylan

In reply to:

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Hmm, I am starting to wonder if perhaps this is not something the Empeg people or one of us should build something for.

---

Absolutely! There is so much possibility with the empeg. It's a general purpose computer with a microphone input, moderately flexible hardware DSP, infinitely flexible software DSP, and plenty of processing power. There is a world of possibilities for auto calibration in both the frequency and time domains. I'm sure Empeg has thought down these lines though it's not easy to do correctly.

-Dylan

I just took a look at the logs and noticed that some of you are downloading both the WAV and MP3 versions of the same track. That's entirely unnecessary and a waste of my limited bandwidth. If you download the WAV files you can encode the MP3's yourself using free software. Please don't do this or I'll be forced to start kicking users off.

-Dylan

Yeah these would be nice to mirror for the good of all Empeg-kind. Especially dialup lamers like myself.

-Tony
MkII #554

The DSP isn't remote flexible in terms of software - it's mask programmed by Philips.

If you want tones and so forth, then that's moderately trivial. Maybe John could release some code fragments to do it - unless we got the data from NDA'd Philips documentation in which case you'll have to work it out for yourselves.

Rob

I can't offer a mirror as such, I don't trust the Win2k ftp server enough to turn it on...

However I am sharing them via Napster, my user name is andynormancx (so you can add me to your hotlist, then you can see all of the files in one go).

I have 256kb/sec upstream, so that should lighten the load a bit.

N.B. I haven't got the whole set of files, just the MP3s. I also don't have tracks 89-91 (because I have no idea what they are).

__
Unit serial number 47 (was 330 in the queue)...

You got it! I'll be putting these up on Napster shortly. I'm under Skirge01 (that's a zero!). I'm in the process of ripping the waves into MP3's again, since I found sound artifacts in the ones I downloaded. Speaking of which... sorry about downloading both. I just did a "CTRL+A" in GetRight and never even looked at the names. Seems that it's good I downloaded both, though. Gimme a few minutes, since I'm also filling out the ID3 v2 tags.


George

Oops. I just found out I was missing tracks 62-92 of the wave files, so I'm going back and downloading them. I'll rip those into MP3, throw in the ID3 v2 tags, and post them on Napster. In the mean time, I'm going to log on to Napster and let people start downloading the first 61 tracks. I've got a 384k upstream connection and will be limiting each person to one download at a time.

George

Since I couldn't get onto Napster (uh-oh... are they dead? Probably not, just server trouble, hehe.), I downloaded a little FTP program and set it up. Following the lead (why use a different one?):

login: empeg
password: incarmp3
IP: 216.20.160.44, port number 21

Let me know if you have any problems! Remember, I only have tracks 1-61 right now, but I'm working on it!


George

Edited by georgelsjr on 15/10/00 06:34 PM.

In reply to:

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I'm in the process of ripping the waves into MP3's again, since I found sound artifacts in the ones I downloaded

---

I'd be curious to know if you find a way to encode them better. I used LAME at it's maximum bit rate and highest quality setting. Everything I've read says that LAME is the best encoder available.

-Dylan

I'm not sure whether it was an encoder issue or just a flaw during in the encoding of the tracks (something running in the background of your system or whatever... I really don't know what would cause it). I played a few of the mp3's on my system and heard some breaks, so I listened to the wave files and didn't hear them. So, I ran the waves through Audiocatalyst at the highest settings all around and the breaks disappeared. I even tried using VBR and they came out the same (no breaks), but I figured, given the subject matter (audio quality), it would be best if I just encoded at a constant 320k. So, I honestly don't know where the artifacts came from, but they aren't there on the ones I recorded. If you want any more info, let me know.

George

Just a quick update on my progress. If you're logged on while I'm doing this, you may need to refresh the directory to see the newly added files. It's taking a little longer to download than I had anticipated, due to the 10k limit and the fact that some of the remaining files are quite large! I'm working on it, I'm working on it!

George

Hmmm, since so many of us seem to be downloading these would someone be willing to create a howto for using them for those of with limited tuning experience?

-Mike

Well, I've gotten as many as I'm going to get for tonight. The remaining three are currently downloading and they're gonna take a little while. But, 1-89 are up on the mirror as both waves and MP3's. Enjoy! I'll have the other 3 up tomorrow night.

George

Yeah, what on earth are tracks 89-91 all about ?

__
Unit serial number 47 (was 330 in the queue)...

SMPTE ("simpty") is a time code system for synchronisation, and was created by the US Society of Motion Picture and Television Engineers.

So guessing from the track names (having not listened to them) they are to test studio synchronisation equipment.

This page seems to have some good technical info on it.

Jazz
(List 112, Mk2 12 gig #40. Mk1 4 gig #30. Mk3 1.6 16v)

In reply to:

---

I played a few of the mp3's on my system and heard some breaks, so I listened to the wave files and didn't hear them.

---

Can you (or anyone else) tell me which tracks? I've not yet listened to all of the MP3's but I haven't heard any problems on the ones I have listened to. I'll re-encode any that have problems.

-Dylan

Yep, the final 3 files are up as of now. Is anyone getting a really slow connection? I haven't put a limit on bandwidth, since I didn't know what type of response to expect. The numbers look pretty average, though, so it doesn't seem that anyone is hogging it all.

George

I may be needing my bandwidth back soon so I might be taking the server down. Consider yourself warned. I'll leave it running as long as it doesn't interfere with what I need to do.

George has already put up a mirror and, as of this morning, 20-30 people had downloaded each track from my server so the files should be distributed enough that others can share. And I know from my logs that some of you have plenty of bandwidth.

-Dylan

For some reason the connection with Dylan's server froze up every few megabytes, even then it was only 3K per sec. So I moved over to George's server. There I am only getting about 1.25K per sec. I am on a very capable connection so it's dissapointing to get such low speeds. I intend to put up all the tracks on two good servers here when I get them. I am trying to get the wav files now. If anyone has these and has a fast connection would you consider setting up a private connection?

Alex Lear

I'm not sure why you're getting such a slow connection. On Dylan's I got a steady 8-12k/sec. and most people on mine seem to be averaging around 12k. Have you tried pinging it to see if there's a slow link along the way? I haven't seen any more than 3 people online at any one time and it's generally only 1 or 2 people. Weird. I wonder if the server software I'm using (Serv-U) is causing the slowdown? Oh well... I'm doing what I can.

George

In reply to:

---

Hmmm, since so many of us seem to be downloading these would someone be willing to create a howto for using them for those of with limited tuning experience?

---

This is what I did. I welcome other ideas for how to best do this. I have some familiarity with this topic but am far from an expert.

I used the 1/3 octave band tracks (10-40) along with an SPL meter in an attempt to equalize the db reading at each frequency band. I selected a volume level on the empeg that was about my usual listening volume then I quickly went through the octave bands to establish a rough average db level. This also gave me an idea up front where the major problems were in my system. (I was pleased with myself that the guesses I'd made by ear were in the ballpark.)

I don't have any real procedure I can give. I pretty much just went through all of the 1/3 octave bands and identified the frequencies where I needed to make corrections. It was a trial and error process of determining which frequency I should use for each band and what the adjustment and Q needed to be.

I think the best approach would be to record the reading for each 1/3 octave and then graph it out. That will make it easier to choose the 5 or 10 bands to adjust. Probably the thing to do is pick the frequency that is at the peak of each hump or dip. With the empeg's flexible Q setting you should be able to dial in the proper slope for each hump/dip.

I didn't set up any special playlist other than having the tracks in CD order. It was a hassle switching back and forth between the equalizer and controlling the track being played. What I wanted when I was doing this was to have a repeating loop of 3 or 4 bands so I could just stay in the EQ menu. So when I try this again I'll set up playlists to accomplish that. (Will the player cycle to the beginning of a playlist or will I need to explicitly repeat the tracks in each playlist?)

The SPL meter I used and the one that is ubiquitous in the home theater world is Radio Shack Cat.#: 33-2050. It's an analog meter that costs $35. Don't get the more expensive digital meter as it's less accurate. Here is some information on the RatShack meter. Do a search at Google and you'll find more interesting links.

After typing up this post I see some things I can do better. I figured that I'd end redoing it after learning from my first attempt. I think that by plotting out the results, applying the corrections for the meter inaccuracy, and putting some forethought into it I should get better results. That being said, I'm thrilled already with the improvement I was able to make. I put new speakers and a new head unit in my car when I got it last year. I'd intended these to be the first steps towards a great system but I was so disappointed in the sound quality that I gave up. The acoustics in my VW Passat Wagon are lousy. I have some enormous frequency anomalies that could not be corrected with the course adjustments in my head unit. The EQ in the empeg allowed me to make it much, much better. Now I'm excited again about the system in my car.

This is all a bonus as far as I'm concerned. I bought the empeg because I wanted all of my music in my car at my fingertips. I knew of the EQ but it wasn't a factor in my buying decision. I'm pleased as punch!

-Dylan

Here is some information on the RatShack meter.

That page sounds like it knows what it's talking about but there's a contradiction with the meter manual. According to the manual, the reponse of the meter rolls off sharply above 10kHz. The above page claims that it's still flat (+/-1dB) up to 20kHz. What gives?

Borislav

I will be happy to post all these WAV's and MP3's on my webserver...which has good DSL connection speeds...you should be able to get 50kbps easily over that connection.

But I'm having trouble downloading them to begin with. EXTREMELY slow or flakey connections with both the original FTP as well as George's mirror. If anyone wants to point me at a faster site, I'll mirror them also...

-steve

In reply to:

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EXTREMELY slow or flakey connections with both the original FTP as well as George's mirror

---

I have no idea why it would be extremely slow or flakey. My logs confirm that I've been maxing out my 384 Kb DSL connection for most of the past few days. Many people had long, uninterrupted sessions and achieved throughput of 15-30 KB depending on how many concurrent sessions there were.

The site has been down today, however. I needed the bandwidth for other purposes.

-Dylan

Ah...that's cool. I'll try later tonight and see if it works better.

thanks again

I have created a mirror of the audio calibration tracks. Get them while they last:

http://www.bstage.com/AudioTest/

-steve

Thanks Steve. I guess you've got quite a bit of bandwidth to spare. That being the case, I've taken down my server. I haven't seen anyone log on for the past two days, anyhow. If anything goes wrong or whatever, I'll be happy to put them back up, though don't expect the speed you're probably getting from Steve!

George

Is this server still up? I can't get to it...
Thanks

_~= Dearing =~_
"WAY too happy about having #99."

The audio calibration wav's/mp3's are available on my hotline server at 153.90.196.23.

Or you can get the mp3's from me (gal0801) on the napster server Dylan has set up.

Let me know of any problems!

Alex Lear

The original mp3s are also available via napster from me (andynormancx)

__
Unit serial number 47 (was 330 in the queue)...

In reply to:

---

I ripped and encoded a CD called Sound Check from the Alan Parsons Project. It's called a "Professional Audio Test Disc" and it's got lots of test tones and other tracks to help in calibrating a sound system.
...
Send an email to audiotest@theginsburgs.org for ftp instructions. That's an autoresponding address so I won't see anything you write.

Please heed the warning in the email about track 59.

---

I've just retrieved these files from the web mirror at http://www.bstage.com/AudioTest/ (thanks, dewdman42!).
Where is track 59? It's not on the mirror, and the autoresponder is no longer responding, so I don't know what the warning said.

Cheers,
- Sean

I'm pretty sure that's the track that is at full levels or volume (not sure what the correct term would be), and so was dangerous in that it might blow your speakers if you weren't aware of what it was...

correct me if i'm wrong fellas.


|| loren.cox
|| 080000446

Does anybody know if these are still available. I've recently had my empeg put into my Beetle and would like to try these out to set up the EQ. I had them the first time round but have since lost them in a few hard disk wipes and never made a hard copy of them.

Thanks in advance.

I have the original CD, but I don't have access to a decent machine at home to rip it right now. Ummm.... let me get back to you on that !
Steve.

I have a copy, I have sent you a PM.

Im interested in this, too...

cheers, Thomas

Me too! Me too!

Cheers,

A.

and me !

me too!

I'm in!

I don't suppose someone could put these some place accessable to us all?
If not could you point me in the direction of where they are.

In reply to:

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I don't suppose someone could put these some place accessable to us all?

---

That would be great. I've been looking for a good test CD.

Stu

I have these on my webserver and I have aleady pointed a couple of people who PM'd me to them. However I am reluctant to give the address out to everyone for two reasons:

1: They are copyrighted material and I am not too keen to hand them out to all comers (hypocrytical I know)
2: More importantly, my server is on the end of my 1024/256 DSL line