I just got my 2nd company car with stock car stereo (a Fujitsu Ten CD player) with just Bass and Treble controls for enhancement. I would just assume that the frequencies adjusted by the said controls would be 100 Hz for bass and 10 khz for treble, since the manual did not specify them.

Since there is no built-in equalizer (or any other DSP for that matter, and I don't want to spend for a new head unit or equalizer hardware), I am wondering if I burn my favorite CDs to CD-R with Nero 20-band equalizer (setting: Loudness - light) with be destructive to the music. I plan to play them in the car stereo with flat line setting (no bass and treble adjustment; at zero setting.)

In short, equalization will be done at the CD burning level, rather than at the CD playback level.

I tried searching in the forum regarding this matter, but I usually end up with replaygain/wavgain...

Looking forward for your thoughts!

Cheers!

P.S. CD-Rs are dirt-cheap compared to DSP hardware he he he! I just spent my money on Lanzar tweeters and Pioneer speakers.

While I don't know the specifics of Nero's equalizer, I suspect that what you are describing should work just fine. The only thing that I can think of to watch out for is the possibility that some frequencies could be boosted to where they cause clipping, so either make sure that the equalization only reduces bands and does not increase any of them, or adjust the overall volume down to avoid clipping.

Thanks for that, pdq. I missed the clipping part, though. I'm not sure if I apply the filters normalization and equalization in Nero, which would come first; or are they both applied in real-time.

Maybe I would just lessen the pre-amp volume based on the frequency with the highest gain to compensate. That is, if the highest gain of any frequency across the spectrum would be 3 db, I would decrease the pre-amp volume by 3 db also, rather than apply normalization (which again I wouldn't know when would Nero apply). Would this be the best option?

EQ should always be done before normalization. EQ changes amplitude differentially based on frequency so some parts with reasonable level after normalization might be amplified into clipping by EQ if applied second.

Thanks Andy, at least I'm more enlightened on which should go first if there is a need to normalize. Would adjusting only the pre-amp volume suffice?

I'm afraid I don't know what you mean about a preamp. As I understood it, you are making CD copies. The general path there is CD > extracted wav files > CD-R. Before writing the extracted wav files to CD-R you want to change their overall EQ in some manner; this is normally done with software. No other hardware (i.e. a preamp) seems to fit into the flow anywhere. Whatever you intend, it must be applied before the files are written to the CD-R or it cannot work properly.

Since the majority of commercial CDs have been normalized to a fairly high level, fairly often to 0dBfs, any EQ changes have a high probability of causing some clipping. Therefore you need to normalize down first, to an amount greater than your greatest intended EQ gain. Even a cut at some frequency can cause an unintended increase in level somewhere else, so you need to first compensate for it.

EQ is generally used for two purposes. The first is to compensate for speaker or room deficiencies. You boost certain frequencies, and cut others, to try and make things come out flat overall. This can never be completely successful but you might improve things on the whole. The applied EQ must be carefully calculated and applied against measurements of system response for this approach to ever have much chance of suscess.

The second purpose is to provide for your personal preferences. The mixing and mastering people who worked on the album have gone to a great deal of effort to get what they perceive as the perfect balance. You think otherwise; you like that loud thumpa, thumpa bass or you want the vocal range to be emphasized and out front or ... . In this case you apply an EQ designed to enhance the particular effect you like.

Regardless of which purpose drives you, the level of 16 bit CD must not go above 0dB or whatever did go there is gone forever. Therefore you must first lower the overall file level (equally at every point), then apply the EQ. A preamp in the signal chain is either near the front-end of the recording process, long before you get the CD, or part of your playback system. The kind of adjustments you are considering must be made before the CD-R is written, well ahead of where the music meets the playback preamp. A preamp could only be involved if you are going CD > wav files > soundcard > external hardware > soundcard > wav files > CD-R.

If the pre-amp/EQ works the same way in Nero as in other programs, either leave the pre-amp at 0dB and only move the EQ sliders down (giving the same shape over all, but with the middle bands cut rather than the end bands boosted), or move the pre-amp further down than you've put the boosted bands up (and then some!). The former will prevent clipping almost always, but may sound slightly different because of the way some EQs are designed. The latter may not always prevent clipping (hence the "and then some"), but will otherwise(!) give exactly the sound you expect.

Some people measure the frequency response of their car audio system, and try to correct for it using DSP before they encode mp3s for in-car listening. Some people do this in the home on their stereo, e.g. TACT DRC (Google for it).

Hope this helps.

Cheers,
David.

Thanks guys for your inputs.

After considering the normalization issue for equalized WAVs, I performed a simple analysis of applying normalization and equalization settings on 6 different WAVs (same song) in Nero prior to burning. These are:

• RMS 20
• RMS 20 + preset Loudness (Light)
• RMS 20 + preset Loudness (Heavy)
• Maximum 95%
• Maximum 95% + preset Loudness (Light)
• Maximum 95% + preset Loudness (Heavy)

I burned the 6 tracks in a CD-RW, after which I extracted the tracks via Cool Edit Pro and analyzed the waveform.

Normalization using RMS method may, and in this case, did, cause clipping (even without equalization yet!). Applying equalization further clipped the tracks.

Normalization using the Maximum method did not cause clipping. Adding equalization (Loudness - Light) didn't cause clipping, while Heavy Loudness caused the track to clip.



Much as I would like to have the sequence done this way, Nero applies both filters maybe at the same time in real time, since there is no option to select which goes first, unless I do it manually (but that would be too time-consuming already.) I guess this would be the most automated way to do it.

Therefore, I found my sweet spot in Max 95% with Light Loudness!

Thanks again for your valuable inputs.

I hope this would help someone in the future...

Cheers!