Hello,

i am new to this forum...my name is Olaf and i am from the Netherlands...i am a DJ and i switched from vinyl to CD's a few years ago..currently i am examining why at loud volumes over club PA's i find that vinyl sounds much more "boosted" in the low frequencies compared to playing CD's/mp3s... (i don't want to start a good vs bad war, it's just something i personally experienced over the years and want to explore further)..

my question: i know MP3 uses a lossy psycho-acoustics algorithm that is partly based on losing masked freqs and freqs that human ears cannot hear.... do the current high-end mp3 codecs and algorithms drop f.e. frequencies below 60Hz to get more efficient in compression? This might explain why at moderate volumes there is no real difference but when played at loud volumes over club PA's with subwoofers etc. there is a difference (ie more feeling the lows than being able to hear them) between mp3 encoded audio and vinyl....

any ideas about this?

thanx! Olaf

All lossy encoders I know encode all low frequencies. Also pure DC.

I guess there are lots of possible explanations (non optimal RIAA curve... different mastering etc) but perhaps you'd like to try a little experiment if it's possible. Record the output of the turntables/mixer in the club, burn that to cd and check if the cd still sounds like it has less bass.

AFAIK, vinlyl can't go all the way down to 20Hz ... don't really know the high pass tho. Anyway, the studio engineers compensate by shifting and/or boosting the low frequencies that the record can reproduce. This way, it may seem to have more bass, when it's really just louder bass at a higher freq.

CDs on the other hand can go all the way down to DC, so the studio does not have to compensate, which then gives you a "better" signal, but it might be not as loud.

Try to do what Gecko said... and also see if you can find both a record and cd versions of a song that really exhibit this. Then look at them both using a spectrum analyzer and see if one of them has more bass, and the frequencies they both reproduce.

Actually, there's no reason why 'vinyl' cannot go down to 20Hz. Indeed, I still have an LP in my collection with measurable output down to 16Hz. Is that typical? No. But is is possible. There are a number of engineering reasons why bass output was normally rolled of much higher. A few audiophile records were made with deep bass, but don't bother looking for them. You're not apt to find any.

Hmm.

Sounds like houses in Tuscany.

Capiche?

Well, maybe they're not that scarce. By the way, I am a collector, and if anyone runs across one of these pipe organ recordings from around 1970 on EMI label, please advise here. Thanks.

i've been thinking about the RIAA curve in the phono pre-amps, but didn't find any real proof for this (i need someone who has the original masters before applying the inverse RIAA curve before the cutting, to compare with the signal after applying the RIAA curve in the phono-preamps to the pressed vinyl.... i have some record-deals coming up so i might be able to test this myself in a little while)

about the experiment above:as far as i understand this is the same as recording a vinyl record through a common DJ mixer with decent pre-amps (like the pioneer DJ mixers that are very common in clubs) to CD and comparing this signal from CD to the vinyl record played through the same mixer....my experience with this: it sounds different....less boosted in the lows, more highs..... this is only really apparent when playing at real loud volumes where you can feel the bassdrums, and where the high frequencies start piercing your ears.....compared to the same record on vinyl, which really kicks you in the stomach and doesn't fatique the ears..i *always* have to cut down the high freqs and boost the lows when using CD's.... both CD-R's with decoded mp3's on them, or commercial CD's....

another issue i thought of: the pre-echo thing of mp3 encoding, where attack transients get "smeared" ...this might be something that gets more apparent with loud volumes and deep kickdrums too...

the above is why i am exploring the the subsonic frequencies theory, but it doesn't explain why it's both apparent with CD's and CD-R's with mp3 material...

Olaf

It must be feedback into the turntables.
Record on CD without monitoring the sound, then replay the same track at high volume in the room, still recording.
If it is indeed feedback, the CD will give you the bass in the second recording only.

interesting idea, but i think if feedback really occurs this has to change for each setup..some people use concrete slabs, others use foam etc. so the sound should differ for each setup....

i'm gonna take a look into this though..thanx!

Olaf