Signal processing - equalizers/tone controls

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Adamo0926
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Signal processing - equalizers/tone controls

Post by Adamo0926 » 15 Jun 2019 21:39

What do all of you think about the use of signal processors like equalizers and even the use of the tone controls ?

For the longest time I wanted to think of myself as a "purist".....that I would never use an equalizer and I would always
leave the tone controls set flat....no matter what.....

Was I weird to think that ?

Now the way I have started to think is that signal processing is a good thing to tweak a borderline recording into getting
it to sound better (at least to my ears).

I did have an equalizer in the past and got rid of it. But now I'm considering getting another one....God forgive me....lol.

How many of you incorporate an equalizer into your setup ? And if you do....do you have any recommendations as to a good one ?

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Re: Signal processing - equalizers/tone controls

Post by JoeE SP9 » 15 Jun 2019 22:37

It really depends on what you mean by equalizer and what you intend using it for. If you mean the usual 10 or more band linear equalizer there are quite a few posters that use one. Generally the Eq is treated as a multi band tone control. They also make frequent and liberal use of tone and loudness controls. Then, there are others who use some type of DSP for room equalization. Unlike linear Eq's DSP's are usually used in a set and forget manner. The settings being determined by measurements. DSP users generally don't do much tweaking with tone or loudness controls even if they have them.

I last used a linear equalizer up to the middle 1980's. It was then I moved to an ARC SP-9 preamp from an ARC SP-3. In addition to (IMO) sounding much better than the ARC SP-3 it replaced it has no tone or loudness control. The SP-3 has tone and a variable loudness control.

The linear Eq was retired when I got the SP-9. Currently I use a DSP for room equalization primarily in the bass range. It's used in measure, set and forget mode.

My preamp doesn't have tone or a loudness control. With an acoustically treated room and bass equalized to -2dB@18Hz I don't feel the need to tweak the sound. Of course a lot of this is because of my primary music sources. Jazz and Classical tend to be well recorded. Consequently, there is little to no reason to correct for poor recordings.

I also have some pop/rock recordings. Many of them (IMO) don't sound very good. However, I like the music and accept it with all its warts. When I first brought home Sugar Ray 14:59, I returned it. It made my system sound like it was broken. The second copy sounded just as bad so I kept it. I'm thankful that my musical tastes are such that recordings like 14:59 are few and far between in my collection.
Last edited by JoeE SP9 on 15 Jun 2019 23:05, edited 1 time in total.

Sunwire
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Re: Signal processing - equalizers/tone controls

Post by Sunwire » 15 Jun 2019 22:45

I use a digital parametric equalizer on my computer for digital music, which is 99% of my listening.
I don't use an equalizer for LP playback, but mostly what I do is record the LPs to my computer, then play the files back from the computer with EQ.
The digital EQ I use is the free posihfopit edition of the Electri-Q VST plug-in for the foobar2000 player.
http://www.pcjv.de/vst-plugins/eqs-filters/electri-q/
I know there are others, but haven't investigated recently.

On another system, I use a hardware parametric EQ. It's a Technics SH-9010, which is extremely versatile.
http://www.thevintageknob.org/technics-SH-9010.html

I think there is nothing wrong with using an EQ.
The "purist" approach makes sense if you have perfect speakers in an acoustically perfect room and you always listen to music at realistic (quite loud) levels.
Amps, preamps, and receivers from the 1950s-1980s usually included tone controls, high and low filters, and loudness compensation because these are all very useful features for listening to real recordings in real home environments where things aren't perfect.
More recently, the "purist" approach took over. This allowed manufacturers to cut costs by eliminating a lot of parts, without cutting prices. More profit for them!

If you want to incorporate an EQ, please note that the greatest need for use of an EQ is adjusting the bass frequencies, especially the very low bass frequencies. This is the region of the musical spectrum where the majority of problems occur due to speaker limitations, room acoustics, and the characteristics of human hearing. The frequency response of our ears changes radically depending on how loud the music is. At low volumes, we just don't hear low bass frequencies very well. The loudness button or variable loudness knob on some preamps, amps, and receivers was designed to compensate for this. Switch it on for low to moderate volume listening, switch it off when you turn the volume up to "realistic" levels.
You can achieve the same effect with an EQ.
Look for an EQ with controls that affect the very low frequencies (20 or 30 Hz). If the lowest control on the EQ is at 60 Hz (common) it won't be very useful for adjusting ultra low bass.

Since someone else will probably jump in with this comment, I should say that the "purist" approach is not without merit. An EQ can cause a slight loss of sonic clarity and coherence, added distortion, and possibly a bit of added noise (usually inaudible). If you want the greatest clarity, especially when listening loud, switch the EQ out of the circuit. For other conditions, especially more casual listening when you want to hear the deep bass at low volumes, switch the EQ on.

As for specific models, I can recommend the two I have used:
Technics SH-9010
Ashly Audio SC-66A (this is a professional EQ)

I no longer have the Ashly. I wish I had not sold it. I greatly prefer knobs to sliders. They are much easier to set precisely.

They are both long out of production, but can sometimes be found used.
Others may be able to recommend newer or more easy to find models.

Adamo0926
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Re: Signal processing - equalizers/tone controls

Post by Adamo0926 » 16 Jun 2019 05:51

Thanks to both of you for 2 very detailed posts. My Yamaha has 3 tone controls for bass, presence (midrange), and treble. The bass and treble controls can switch between 2 frequencies. Plus the loudness compensation is variable and not just an on/off button. So it's kind of like a poor man's EQ.

Sometimes I think I might be listening too critically....music should be emotional and not just technical. If it moves your soul then it has reached it's full potential. Whether or not you can clearly hear that clink of the triangle at a certain point in the song....

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Re: Signal processing - equalizers/tone controls

Post by zlartibartfast » 16 Jun 2019 15:57

The Yamaha tone controls are actually pretty good, especially the variable loudness. There's nothing wrong with getting into the weeds with your equalization, as long as you don't spend all of your time there!

JoeE SP9 and Sunwire have covered the topic very well, so there's not much to add. A word of caution, however - I've damaged speaker drivers with excessive EQ settings before. Be judicious! You can get more bass by turning down the treble....

I like parametric EQ's. I have an SAE EQ-10 that I got for $100, and it does the job.

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Re: Signal processing - equalizers/tone controls

Post by JoeE SP9 » 17 Jun 2019 21:14

The variable loudness control on many Yamaha products is IMO a definite plus. The only thing I really miss from my old SP-3 is the variable loudness control. It was used regularly while the tone controls got almost no use.

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Re: Signal processing - equalizers/tone controls

Post by Alec124c41 » 18 Jun 2019 13:48

Love the old Yamaha products.
I have been known to add a notch to the bass ... ;)
Recordings vary, speakers vary, rooms vary, and personal tastes vary, often with different genres of music.
Use whatever works for you.

Cheers,
Alec

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Re: Signal processing - equalizers/tone controls

Post by jdjohn » 19 Jun 2019 22:55

It takes a lot of time, effort, and money to build a system which does not benefit from some form of tone control.
Time, Effort, Money: most of us lack at least one of those, so there's no shame in using those knobs :)

Bob Dillon
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Re: Signal processing - equalizers/tone controls

Post by Bob Dillon » 20 Jun 2019 02:22

I have three way control, bass-mid-treble on my amp, plus a hi-filter button. I wouldn't be without tone controls, though they are usually left at flat setting. If somethiing is really needing it, I'll use the controls, otherwise I can adjust on my own. I don't do something like grab the bass knob and crank it to 5 o'clock, I find that kind of thing fatiguing. A little nudge of the mid control in either direction is what usually does the trick. I'll sometimes use the hi-filter too on older stuff with a lot of tape hiss, or record surface noise, like 78 rpm scratch. Although I have a Parks Audio Puffin phono stage that can do the same kind of thing thing and much more (with records anyway), sometimes a simple flick of the hi-filter is still just the easiest option with noisier program material.

Once upon a time I used a Soundcraftsmen RP 2201-R EQ. It was a dual 10-band unit from the early 1970's. I used to use it a lot for tweaking recordings to cassette and other stuff. I used it for years, and now it's been retired for years. It's enjoying it's relaxation time in a box in the closet. I don't frankly have any more use for a fiddly graphic EQ like that. I'd go parametric if I was ever going to wire in a analog EQ unit again. I doubt I would though.

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Re: Signal processing - equalizers/tone controls

Post by JDJX » 28 Jul 2019 15:51

There was a time when hard core audiophiles all used an EQ as no two acoustical environments are the exact same. Now an EQ seems to be the devils tool, by those who have no real idea about how to use one.

I could never understand those who say that they are "purest" but settle for an impure sound due to an acoustical environment coloring the sound

Having sad that, tone controls are there to be used.
I also recommend that for the average home system that all you really need is about a 10 band per channel EQ .
Sometimes, a slight tweak in one or two "key' bands is all you need to flatten out the sound.

You can have low distortion etc but if you have a frequency imbalance, it's all for naught. :)

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Re: Signal processing - equalizers/tone controls

Post by Bob Dillon » 28 Jul 2019 20:07

Get a Schiit Loki.

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Re: Signal processing - equalizers/tone controls

Post by JDJX » 28 Jul 2019 20:39

Bob Dillon wrote:
28 Jul 2019 20:07
Get a Schiit Loki.

That may be all some systems need .:)

However a 4 band EQ is limited, and, the individual 4 bands bands that the Loli covers is spread over a very wide frequency range area...

In other words you can't make adjustments to a needed narrower frequency range that might need adjustment.
For example, in my 10 band EQ I only have a 3db cut in the 120 hz range and another 3db cut in the 2k hz range.
Of course, any EQ setting is only valid at you normal listening level .:)

https://www.superbestaudiofriends.org/i ... ents.5153/

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Re: Signal processing - equalizers/tone controls

Post by Sunwire » 28 Jul 2019 22:26

I think a 5 band EQ would be enough for most situations if it had 3 bands to cover bass (approximately 40, 80, 120 hz), 1 for midrange, and 1 for treble.

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Re: Signal processing - equalizers/tone controls

Post by JDJX » 29 Jul 2019 00:05

Sunwire wrote:
28 Jul 2019 22:26
I think a 5 band EQ would be enough for most situations if it had 3 bands to cover bass (approximately 40, 80, 120 hz), 1 for midrange, and 1 for treble.
When I built my Heathkit system in the '70s (which included a 1640 amp) I also buit this 5 band EQ and its matching, companion Pre amp .

It was all I needed as the 5 bands were all centered at all the right frequencies.

BTW, a good 10 band EQ will also have all the bands centered at the most useful frequencies. :)

A pic of the Heathkit from the net.
0xHeathkit AD-1305 EQ.jpg
(28.18 KiB) Downloaded 104 times
EDIT......

BTW this was all that I built. (also a pic from the net)
The system also included JBL L-100 speakers , and a Thorens 145 with a V-15 Type IV.
I wish that I still had all that of course. :)
oHEATH739_bb1ce04aed_c.jpg
(78.77 KiB) Downloaded 103 times

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Re: Signal processing - equalizers/tone controls

Post by JDJX » 30 Jul 2019 16:56

BTW, keep in mind that the JBL L-100 has " L- pads" on the tweeter and mid range drivers to adjust their output.

Most increased the mid range slightly as I also did.
The L-100 tended to have what was called "the west coast sound".... which meant that the bass and hi end was just a tad too prounced.

I mention this to illustrate how all audio hardware has to work in synergy..... or complement each other to produce the best sound balance and careful adjustments are usually needed. :)

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