Spinning 78's through an RIAA applied EQ Curve- Adjustments?

Discussion in 'Turntables' started by Arthur Smith, Aug 30, 2017.

  1. Arthur Smith

    Arthur Smith Well-Known Member

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    I set up my AT120LP-USB AT95E cart (one of them) with a 78 stylus. I played back a disc last night, and to my ears, it sounded decent, certainly listenable. But, given the RIAA curve a modern day phono preamplifier applies, what tone adjustments do folks like to make to bass, treble, etc, to get it to sound more like the way it was originally listened to, without the curve applied?
     
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  2. vwestlife

    vwestlife Active Member

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    At this point unless your 78s are in pristine condition, your tone control adjustments are better spent mitigating surface noise and making each disc sound the best to you than trying to exactly match the original emphasis curve, which varied drastically from one record company to the next and was continually tinkered with until the industry agreed on the RIAA curve in the 1950s.

    For example in the early 1930s there were some early attempts at "high fidelity" 78s with much greater treble response than before, but they had to tone it down because the crude acoustic phonographs that many people were still using had trouble tracking the high frequencies.

     
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  3. eb2jim

    eb2jim Super Member

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    For me the process has always been a bit of a wildcard. On one hand there are several known eq curves used by different companies in the era. My 78 collection while modest spans wwI through the end of the 50's. On top of that some were played by nail-quality needles, especially my blues discs. So a while back I just accepted the preamp I have and adjusted individually, sometimes with my eq but mostly by adjusting the tone and balance.
     
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  4. Arthur Smith

    Arthur Smith Well-Known Member

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    These are great thoughts. Last night, I had some nice results with an Ella Fitzgerald 78 by pulling down the treble slightly, and turning the bass slightly up. This of course was an orthophonic recording. I do have some older acoustic ones, that should be interesting to experiment with.

    I did find it amazing that Audio Technica puts almost no warning in the box to change cartridge/stylus to accommodate the wider grooves of the 78. They probably mention it, but in a very rudimentary way. Have seen several folks online destroy their microgroove styli as a result.
     
  5. 4-2-7

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    None of these 78s are designed for the cart and stylus you are using, let alone the rest of the equipment your running it though.
     
  6. Arthur Smith

    Arthur Smith Well-Known Member

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    Maybe not, so why do they sounds so good?
     
  7. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    Sound is subjective, if you think it sounds good then thats fine, but you might as well start ordering more stylus for your cart.
     
  8. Arthur Smith

    Arthur Smith Well-Known Member

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    At a life of 300 hours, not sure it's something I need to fret over anytime soon. 78's are fun!
     
  9. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    You will not see that life out of that stylus, playing these records.
    Steel phono needles even needed to be thrown out on every play.

    imgres.jpg basic.jpg
     
  10. Arthur Smith

    Arthur Smith Well-Known Member

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    Tracking at a blistering weight of 2.5 grams. Happy spinning! A
     
  11. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    Steel impregnated shellac....:rolleyes:
    actually Iron
     
  12. Arthur Smith

    Arthur Smith Well-Known Member

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    Which is meant to be played. And, you might want to get your facts straight regarding composition. Such as the laminate used in Columbia 78's.
     
  13. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    Get a dozen new stylus. :crazy:
     
  14. Arthur Smith

    Arthur Smith Well-Known Member

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    Happy spinning!
     
  15. s rassi

    s rassi Member

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    I admit to being confused. I thought the whole point of having a "78 stylus" was that you can play 78s with it...
     
  16. tubeactive

    tubeactive AK Subscriber Subscriber

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    Arthur, Welcome to the world of 78s via an RIAA phono stage ! I am thrilled you are enjoying the sound. Home HiFi is really about the enjoyment factor. Nobody can take away our enjoyment. However, some folks can possibly help you increase your enjoyment factor.

    Since you are using a USB compatible table/preamp, perhaps you can check out the audacityteam website. These folks are at the forefront of analog to digital conversion. Their programs are tailored to use no preamp EQ as they provide the proper curves. Check out their ultimate collection of EQ playback charts and recommendations. They deserve highest accolades for their compilations of playback info for us spinning discs. They cite another site, midimagic as their "go to" reference. Both of these sites are very informative and enlightening.

    Now, let's get down to your AT-95 with 78 stylus. Is it a sapphire or diamond ? 2.7 mil or 3 mil conical tip ? 300 hours is a conservative amount for a genuine diamond. 50 hours of spinning/playing time can be a liberal amount for a sapphire. Condition of discs and styli governs real time allowance. Let us dissect 50 hours, shall we ? An average of 3 minutes a side is about 20 sides per hour. 50 x 20 = 1000 sides. That's a lot of music, even for a sapphire tip. I examine my sapphire tips often, under a microscope, and keep my discs clean. I can get a few hundred hours from a sapphire tip if I am very careful about the cleanliness.

    Arthur, your original question seems to focus on how to get better sound. RIAA EQ was not "standardized" until the mid-1950s. In spite of the declaration by the RIAA in 1953 and record companies agreeing to conform in 1954, many record cutting engineers, producers and company men held out for various reasons. More important than why is the availability before the RIAA EQ, originally known as RCA's "New Orthophonic" playback curve. Stateside, there were about four "usual" curves in use by 1954. Unfortunately, in Europe, there were a different set of four. Recordings from the UK and Europe which were transcribed for the American market were actually uncertain in their EQ choices depending on vintage ! We can all see how having many playback EQs on hand can be helpful.

    Orthoacoustic and NAB EQ curves were established before WW-II. Most EQ curves specify a Turnover and Rolloff frequency and some include what is known as Bass Shelving in order to reduce rumble and woofer pumping. Orthoacoustic and NAB EQ used a 500 Hz turnover. The RIAA curve also specifies 500 Hz. This is the asymptote frequency which is +3 db above the 0 db reference at 1000 Hz. However, Rolloff differs. NAB specifies 1592 Hz(100 uSec time constant) as the (asymptote or changeover) frequency -3 db below the reference of 1KHz. RIAA specifies 2122 Hz (75 uSec) as their EQ rolloff point. So, to simplify, playing an NAB "encoded" disc with an RIAA "decoded" phono playback curve, the RIAA EQ will provide less high frequency cut, less rolloff. Also, with the bass shelving being slightly different, the RIAA playback will most likely have a bit more low bass boost. You see, most playback EQ curves use a 6 db octave slope, boosting freqs below the specified Turnover and cutting freqs above the specified Rolloff.


    In the above example, RIAA EQ is not that different from the NAB or later Columbia "LP" EQ. As you mentioned, simply reducing treble a bit increased your enjoyment. Way back then, there were other EQ curves which specified 250, 300 or 400 Hz turnover. Playing a 250 or 300 Hz turnover encoded disc with a 500 Hz turnover decoding playback curve can change the sonic character of some musical instruments. With a dull sounding disc, beginning the upward slope toward the bass boost above the encoded turnover freq, can sound beneficial, since we are boosting some mids which define instrument character.

    While many post-1926 and prewar discs were cut with 300 Hz turnovers, some were cut with 500, 630 and even 700 Hz turnovers. The term "house sound" can be applied here, appropriately. In 1951, the AES, Audio Engineering Society, developed a playback curve "averaging" among the many house sound EQ variations. Their reasoning was exemplary. If the record makers could standardize, conforming to producing discs which sounded very good utilizing this "AES" EQ for playback, more discs could be sold. The audio biz could grow and audio companies could prosper. Most importantly, our home HiFi enjoyment factors could be increased which would also sell more hifi gear. The AES EQ curve has become essential in increasing both my 78rpm playback enjoyment as well as my early LP and 45 rpm enjoyment. Too many 1950s record companies persisted conforming to this EQ curve and some even did not disclose that fact !

    The AES EQ specifies 400 Hz turnover (398 uS) and 2500 Hz rolloff (63.5 uS). Bass boost shelving was optional for the recording engineers, as long as their discs sounded good using this playback curve. There is another spec which is very important in sorting EQ curves. That is the "db cut at 10KHZ" spec. NAB EQ is -16db at 10KHz. RIAA EQ is -13.7 db at 10KHz. AES EQ is -12 db at 10KHz. Yes, folks, things get confusing. If we play an early 78 or AES type disc with the RIAA EQ, highs will be cut and we will hear this.

    Then, there are the discs which may sound best with a 700-800 Hz turnover. There are no inexpensive preamps or equalizers which get all this right. Equalizers, like graphic or parametric types, do not conform to the sloped curves used by the early record makers. Neither do normal bass and treble controls. However, tone controls and equalizers can indeed help increase playback enjoyment factor.

    What is best is finding, resto-modding or making a phono preamp which has multiple playback curves easily switched in. The fact is that the small db increment differences among EQ curves are clearly heard and switching in the correct EQ will be easily heard. Quick switching is much easier than fiddling with equalizers, but this comes at a price or electronic building skill level.

    For now, keep on enjoying the spinning discs. Everything sounds good by itself. RIAA EQ and tone controls is certainly going to sound better than an acoustical horn equipped electrola phonograph system. Check out the audacity and midimagic sites to put this info in perspective...
     
  17. Arthur Smith

    Arthur Smith Well-Known Member

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    This is a hobby, a passion, not a "deep in the weeds" kind of thing. It's for fun. It is a 3 mil diamond stylus. I have ZERO interest in Audacity digital transfers. None. Too kludgy and time consuming. What I might do is hook the turntable line output into the "CD Direct" input on my Onkyo preamp for as flat a curve as possible, and see how it sounds. A
     
  18. hi*ball

    hi*ball Records & Coffee Subscriber

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    ^ This is the standard type response from the OP. ^

    Ask for help, get lots of good advice, blow it off as either "myth", "voodoo" or overkill, then do his own thing (or whatever Youtube or Google says is better).
     
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  19. 4-2-7

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    Yep, tubeactive gave him a lot of time and info.
     
  20. vwestlife

    vwestlife Active Member

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    Even the 78 RPM speed (78.26 to be exact) wasn't standardized until the late 1920s, IIRC. Wind-up phonographs had variable speed controls and people would just listen to the music at whatever pitch sounded correct to them. 78 RPM was chosen as an approximate average of the various speeds that had been in use (60-100 RPM) in the early days of disc phonographs.

    And when playing those early acoustically-recorded discs, the EQ curve I use (in addition to the RIAA curve built into the pre-amp) is visible in the background of the video -- I boost the upper bass and midrange, and sharply cut the treble:

     

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