The latest (still experimental) 78 RPM EQ Curve Generator can be downloaded by clicking this link.
Many moons ago there was a feature request for a way to import/export Equalization curves (without needing to manually edit the EQCurves.xml file). This feature is now available in the latest “Nightly” build of Audacity.
(see here for Audacity nightly builds - http://wiki.audacityteam.org/index.php?title=Nightly_Builds )
This new feature is implemented with a “Manage Curves” dialogue accessed by a “Save/Manage curves…” button. This button replaces the previous “Save As” and “Delete” buttons. “Custom” curves are now called “unnamed”.
This is an opportunity for Audacity users to contribute Equalization curves they would like to be available either as “default” presets that all users will have, or as “optional” presets that can be specially imported.
“Manage Curves” provides an easy way to manage pre-set curves. You can save unnamed curves to the list of curves, rename, re-order or delete individual or multiple curves, and import/export .xml files containing individual or multiple curves. When you change the curves list, an automatic backup is made to EQBackup.xml, so if you make a mistake you can import that backup file. You can also restore the presets to the default set, which removes any customised curves you saved.
The new default curves set is not finished yet and so far only contains curves for amradio, acoustic and 60 Hz notch. EDIT:The Windows Nightly Build includes the preliminary default set EQCurves.xml in the same folder as the executable. On Mac or Linux you can download this default EQCurves.xml at “Proposed default curves” on: http://wiki.audacityteam.org/wiki/EQCurvesDownload . Place EQcurves.xml in your Audacity installation folder for Audacity to find it. Please paste new curves for the default set on: http://wiki.audacityteam.org/wiki/Default_EQCurves .
The easiest way to create a curve is to save it, then export it with the name you like. Audacity will add an .xml extension to the file name. Include “default” or “optional” in the file name so we know what usage you think the curve should have.
As an alternative to posting curves on the Wiki, you can post them here by making them into a zip file and uploading the zip as an attachment in replies to this topic. You can’t attach .xml files directly to the Forum, but you can rename the .xml file with a .txt extension and add that as an attachment. (Please don’t post curves as inline text in your post as they tend to be rather long and forum has a habit of messing up text formatting.)
Extensible MarkUp Language (XML) is pretty plain and the basic format is used by billions of programmers and developers. All you need is the understanding of information headers, start and stop tags, and data or value tags and you, too can read XML – and maybe write it, too.
You do have to be careful not to write something for sound that the Real World can’t execute – or that there are unintended results. For example, if you have a sound track with peaks bumping along at 0dB and filter or remove some of the high frequencies, the loudness of the show may go up causing distortion. How is that possible? You took something away and the values of the show peaks went up???
Welcome to the weird world of Fourier.
In the case of the 100Hz filter, that code was produced in Audcity 1.3. I didn’t actually write that. I drew the curves manually while looking at the Shure published product curves and then exported the data.
If you install the current Nightly build of Audacity, then you will be able to create correctly formatted XML files without having to worry about correct XML mark-up.
With the Nightly version, all you have to do is create your Eq curve in the Equalizer effect, save it, Export it, Zip it and upload it as an attachment to your forum post.
The Eq curve manager in the Nightly version of Audacity will perform all of the necessary formatting to convert your Eq curve to a correctly formatted XML file.
I’m attaching a very rough EQ curve of topical interest based on an idea I came across on the web. Record a clip from an online broadcast of the 2010 Football World Cup and filter out the vuvuzela sounds without damaging the rest of the audio too much. Feel free to smooth or tweak it if anyone likes it.
For anyone interested in recording from 78rpm discs …
I got the data for these EQ curves from a 78rpm record restoration site, which gives curves for a number of labels:
Columbia(UK), EMI, HMV
Columbia(US 1925 onward), FFRR, Victor (some 1925 onward)
Columbia(US 1938 onward)
Victor(some 1925 onward)
Capitol, Early Decca, Mercury
Victor(some 1925 onward, and 1938-47)
MGM, Victor(1947 onward)
I have also generated a second set of curves, which I have called “Anti-RIAA” curves.
To explain, the first set (the original 78rpm EQ curves) should be used if recording from a turntable with a “flat” pre-amp.
The “Anti-RIAA” set are a combination of the 78rpm EQ and the inverse of the RIAA curve, and should be used if (like me) you are recording from a turntable with a built-in RIAA pre-amp. They cancel the EQ introduced by the RIAA pre-amp and add the 78rpm EQ.
I haven’t actually tested these yet; I’m still in the process of getting the TT back in working order, but they look like a good starting point.
Nice work Irish.
Could you post the address of the site that you got these from - if they are used it might be best to credit them.
A couple of points about the XML file;
To work with the new Curve Manager, the list of curves needs to have at the top and at the bottom.
The names of the curves need to be shorter as they are too long to display properly in either the Curve Manager or the Equalizer (at its default window size) - I think the maximum name length should ideally be 30 characters including spaces.
The inverse curves (Anti-RIAA) are probably not necessary as the Equalizer includes a button to invert the current curve. (also, I’m not sure that the Anti-RIAA curves are actually correct - they don’t look to be the inverse of the curves that they say they are).