# Opera and Frequency Response



## Op.123 (Mar 25, 2013)

I thought I should make this post as I'm sure at least some of you are hearing voices very differently to me. 

When a pair of earphones I had been using for a while broke I bought a new, fairly decent pair. I was almost going to return them as the sound was so piercing and bright, frequencies between 2khz and 20khz were emphasised by sometimes up to 20 decibels, at least that's how my ears perceived it, everyone is different. After fiddling around with the eq and running a few sine sweeps I realised that even my old headphones were eq'd on the bright side with a noticeable dip around 800hz-1.2khz. 

It took a while to get a flat eq but in the end I got there and I wholly recommend it for anyone, but especially those who listen to Opera. And, maybe counterintuitively, if you listen to lots of historic recordings in poor sound I'd recommend it even more. 

Firstly, if you want to listen with a flat sound, run some sine sweeps yourself and try and equalise it as best you can. Even studio headphones which are supposed to be fairly flat will have noticeable peaks and dips depending on the person. It also does take a little while of getting used to and can sound a little lifeless at first to those used to having a very bright response on upper frequencies.

But this way of listening does help if you want to hear singers as they sounded in the theatre, and while you might not notice as much difference with many modern singers, those who employed a lot of squillo in the past will sound much warmer. The resonant overtones of a well produced voice peak between 2-4khz and a lot of speakers and headsets will emphasises these frequency for brilliance and detail. If you like that sound, and it can help with orchestral music to define the sound, that's fine, but you won't get a clear picture of a singers voice listening that way. On top of that, lots of historical recordings already have a frequency peak around there so you definitely don't want to add on top of that, it can make some records sound almost unbearably harsh. 

I'm sure there are people here who already listen like this, maybe it's already common knowledge I'd like to know, but I was quite surprised by the difference. Voices have more body, Callas sounds much warmer and the faults in her voice are no longer exaggerated, Tebaldi and Caballé don't have the slightly chickeny sound they sometimes had. Del Monaco doesn't sound like his throat is made of metal, etc. The sqillo adds tone and richness without being overbearing or unpleasant. Sibillant frequencies which can also be overdone for detail reasons no longer make hiss too prominent and singer's Ss and Ts no longer sound bigger than their vowels. 

This is not for those who like the signature, detailed sound you get from headphones but more for those who like to listen to music as though you are sitting in the theatre.

Had anyone else found that flat response is important for operatic listening?


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## BBSVK (10 mo ago)

I don't understand most of what you write, but I know these settings make a difference. The cellphone with and without headphones make a difference already. If you have any more idiotproof advice, I would like to take it. For instance, a photo of equalitzer settings or an exact model of the headphones.


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## ewilkros (8 mo ago)

Op.123 said:


> I thought I should make this post as I'm sure at least some of you are hearing voices very differently to me.
> 
> When a pair of earphones I had been using for a while broke I bought a new, fairly decent pair. I was almost going to return them as the sound was so piercing and bright, frequencies between 2khz and 20khz were emphasised by sometimes up to 20 decibels, at least that's how my ears perceived it, everyone is different. After fiddling around with the eq and running a few sine sweeps I realised that even my old headphones were eq'd on the bright side with a noticeable dip around 800hz-1.2khz.
> 
> ...


Flat response in headphones is a reasonable starting point. Listening to historical recordings--and by this time anything from 1890 to 1990 can be called "historical", depending on who's doing the calling--is infinitely complicated by the infinite approaches to remastering.

To some extent in the 1940's and to a large extent in the 1950's, there was an equalization war among all the commercial record companies, with each company having its own proprietary equalization curve. Virtually all companies recorded with pre-emphasized treble and pre-reduced bass, in the expectation that the process would be precisely reversed in playback--on record players of their own manufacture. Playing back this way would reduce upper frequency noise--from scratches or noisy pressings--while bringing the upper frequencies of the music back down to normal; and cutting the disc with reduced bass would make them easier to track, while the bass component would be brought back to normal. Well and good, but it was never done in a straight line "curve", minus-x at one end and plus-x at the other. Every company employed its own damn proprietary equalization curve, flattening off for a while somewhere in the middle, and in many cases European and American affiliates would release the same recording tweaked to different equalization curves. By the mid-fifties in the US, high-end high-fidelity pre-amplifiers like the McIntosh below would come with multiple equalization toggle switches across the audio spectrum, with a largeish card showing where the toggles should be set for each of dozens of labels.










Eventually the curves proposed by the RIAA came to be more or less world standard, later tweaked to a certain extent by international bodies:



https://en.wikipedia.org/wiki/RIAA_equalization



Now that the discs from this era have come into public domain in most of the world, anyone (outside of the US) can take a random old LP set of a given recording off the shelf, "restore" it, and put it on YouTube or onto a retail CD. Individual competence and taste come into play, and Hilarity Ensues.

Further, when the original companies--or by now the successor conglomerates that have bought them out--go back to the original master tapes to produce a CD reissue, they tend to play with dynamics and playback equalization with some sort of theoretical consumer preference in mind--"hotness" of sound, comfort in listening over headphones, fears that listeners in cars might not be able to hear the soft bits over roadnoise or might drive into an embankment if frightened by the loud bits, on and on.

So that the recordings from the big 1950's LP opera-set boom, particularly those of the ever-profitable Callas, become a total mare's-nest to sort out. I am indebted to Viardots for the reference to Dr. Robert E. Seletsky; a quick Google on his name brings me to this extreme dive into the extreme mess:






Callas at EMI – Divina Records







divinarecords.com





When dealing with reissues of 78s there is a similar tangle of individual preference and competence.

In terms of getting towards a more hall-like experience from, say, electrically recorded Victor operatics from the late 1920's--such was never Victor's intention (I use Victor as an example of what was generally prevalent). There was a temporal gap between the development of electrical recording and electrical_ playback_ in the home; in fact playback lagged behind recording into recent memory. Victor continued to produce acoustic players as its main product, (electrical motors and record changers at a hefty additional fee) and in fact the best, incredibly expensive ones, gave pretty good playback of electric recordings, good enough for the switchover to electrical records to be very dramatic for the average visitor to a salesroom.



https://en.wikipedia.org/wiki/Victor_Orthophonic_Victrola



But the bass was still poor and though midrange--vocal range--could be quite vivid on the best models, hall acoustics would be lost or just muddy up the midrange. Victor addressed these problems, first by beefing up the bass with added tubas (very obvious when these discs are played on modern equipment--you haven't lived until you've heard Galli-Curci doing "Ombra leggiera" with Orthophonic Tuba obligato!), and secondly by taking as its goal making it seem as though Ponselle, say, were there in the room with you, right by the floorlamp, as opposed to off on a stage at the opposite end of an opera house from you. Your capacious front parlor was supposed to supply the acoustic, not a performance hall. Someone gave an exquisitely restored high-end Victor Orthophonic Credenza to the Stanford Archive of Recorded Sound, and at a sound-archivists' conference I attended about 20 years ago they played Ponselle's _Vestale_ disc for the attendees, and I must say there was an astounding sense of presence of an actual singer. And the Orthophonic Tuba retreated into discreet undifferentiated lower underpinning. And no, trying to capture it by sticking a microphone and good recording equipment in front of the thing just doesn't work.

Part of Victor's recording process to get a forward voice and no room acoustic whatever involved deadening every surface in the recording studio, usually with draped fabric. In trying to bring a performance hall acoustic into playback of discs recorded in this way, nothing seems to work to me except synthesizing it, and so far I'm not convinced with the results I've heard. It's getting better though, and is infinitely better than the echo-chambers they used to use in fake stereo. If they're going to go and use it now, though, I wish they'd dial it back some.

What can I say? Everything that comes out is differently done, and you have to go on a case-by-case basis. When playing discs it's best to find a label whose product you generally like, if you can, and then follow the procedure for eating in restaurants: taste for salt and then season to taste.

* * * * * *
If I might make some suggestions to those doing transfers of pre-LP materials, and that includes airchecks/linechecks/AFRS discs: get a pre-amp that can bypass or just doesn't have RIAA or other playback equalization and record off the discs with no equalization. It will be shrill and noisy and maybe bass-poor but you will be equalizing later. Record in stereo even though you're dealing in mono discs; at the end of process you can still mix the tracks and get rid of the vertical component. Record at as high a sample rate as you can and archive the results on DVD-R's as .wav files or whatever you prefer; in the future, when the next improvements in noise reduction algorithms and re-equalization come along, you can redo it and probably do a better job. Noise reduction algorithms work better the more vividly the noise is recorded (hence, no treble reduction before you do noise reduction). It makes it easier to distinguish a click, pop or swish on a given disk from sounds on the actual recording, which will probably not have as sharp transients as the sibilants and fricatives from the singers or the percussion instruments in the orchestra. Same thing goes for stereo noise against mono signal.

If dealing with linechecks/airchecks, especially the big 16-inchers which were almost invariably broadcasting industry standard, be aware: because there was more drag from the cutting stylus at the outside edge of the disc, *playback is often pitched up at the outside and drops as you get near the center; conversely, in recording the groove is moving faster relative to the cutting stylus, and so recording quality is much more vivid, and at the same time recorded volume drops from the outside to the inside of the disc, or vice-versa in the rare case of US discs cut from the inside to outside. You'll have to try to normalize this in editing; don't twiddle in process of transferring, as you'll never keep up, but plan on having to boost the inside grooves some (I recently heard CDs of the 1940 Met Don Pasquale, with Sayão, Martini, Baccaloni and Valentino, where the editor had spliced each disc to match the volume of the previous disc at splice, without first compensating for the drop in volume of the previous disc, so playback level gets lower and lower as you go along and you have to keep raising the volume as you play the disc; then at the next scene the whole process starts again and the volume knocks you out of your chair). Be aware if doing transfers of Armed Forces Radio Service syndication discs that the AFRS was itself doing disc recording on the fly from the network linechecks. The network generally was not trying for logical turnover points (15 minutes was the theoretical limit of decent recorded sound, and the network techs would just change sides whenever it occurred to them that the disc looked like it was getting "full", even if the music was in mid-note), but the AFRS was, for playback purposes. Therefore the network turnover could end up being in the middle of the AFRS disc; and you, as "restorer", will have two superimposed deterioration curves to deal with.


*_*
*This happens in some 78's, including, if memory serves, the HMV Tristan duet with Leider and Melchior.


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## ColdGenius (9 mo ago)

Physics and acoustics are not my field, and my relationship with devices is even rather than intimate. Of course there is a great difference when you listen to music through dynamics, headphones or just through cell. The latter should be immediately outclassed. Others depend on device's technical specifications. I prefer dynamics, even primitive, and use headphones forcedly but, unfortunately, the most of time: in public transport, gym, when I have a break or my child is sleeping.


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