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Old 7th August 2014, 01:01 PM   #21
oshifis is offline oshifis  Hungary
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Ben, if you want to adjust the EQ according to the music on the fly, you need to know that music pretty well. But how do you adjust the EQ if you are listening to a perticular music for the first time?
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Old 7th August 2014, 06:20 PM   #22
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Cool Thanks Jonatan

I will try to research on my side; although you are not giving me much to go on. I ever you come across more specifics, please let me know. I am now dissecting every old electronic and popular magazines I still have. I am also searching through any on-line magazines that deals with DIY audio electronics.

Thanks again,

Ben
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Old 7th August 2014, 07:44 PM   #23
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Originally Posted by benphysics View Post
Hey Bob you are my kind of guy. We are definitely on the same page. I went onto your site and saw your preamp. This is what I want to build; something in the same range with preferably 5 bands (enhanced parametricly variable) including a sub control crossed in the vicinity of 125hz as a bi-amp network. I don't know if you ever heard of an audio decompressor. I made one in the early 70s. I made it differential amplitude variable. When music were recorded onto vinyls, (mind you they still are), the physical size of the groove was too narrow to reproduce the full spectrum of the signal. Therefore, during the recording process the signal was compressed: this means that the lower amplitudes were increased while the higher ones were decreased. The decompressor was a little trickier to reverse the process. therefore I made it differential amplitude variable. In my room, I would reach the same effects as if the band was live inside the room, but we would be inside all speakers facing us. Quite a treat. Hey keep me informed if you decide to revamp that preamp of yours with state of the art components.

Stay in touch,
Ben
"State of the art" components wouldn't change how my preamp sounds. All the parts are plenty good. Correct me if I'm wrong.

I've never been a fan of dynamic range expanders. Compressors and expanders are very difficult to make without audible artifacts, especially expanders. There's the attack and decay times, the threshold adjustment, the amount adjustment. A more intelligent processor might look at the wave shape over time, and maybe even delay the signal just enough to do its processing exactly in sync with the signal. It all sounds easy until you look close at how it affects the music. I designed a 4 band compressor/limiter for one of the listening rooms at Dolby when I worked there back in the 80's. Breaking the function up into four bands of frequency made it possible to minimize these artifacts. As a special effect an expander might have its place, but for home listening where you don't want to mess up the dynamics of music audibly, I prefer subtle compression. It makes the music less irksome, and easier to listen to over time.

I suspect that the reason some people think vinyl sounds better than CD's is because of this compression. But also the record acting as a very short and tight reverb spring, when it vibrates when stimulated by the needle vibrating. Almost a subtle chrorus effect below the level of consciousness. A warming effect.
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Old 13th August 2014, 04:28 AM   #24
donovas is offline donovas  South Korea
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Originally Posted by a.wayne View Post
The music is already eq'd , why necessary to do again after, i do find eq is mostly needed when the coloration is high in the system, same as massive room Absorption.

Go for low coloration, true to size speakers and you will find no need for eq ...


My 2c
because they don't EQ specifically for you
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Old 13th August 2014, 07:50 PM   #25
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Cool I do not live on a flat line

I'm 63 and have been an audio enthusiast since I was about 12. I can never get enough in every aspect. I've invested hundreds of thousands $ in audio equipment, commercial and DIY components. I ended up going DIY all the way since I was 30ish, for no commercial products were good enough or they were simply prohibitively expensive even in my standards. I was able to do much better DIY for a ridiculously small fraction of the money. I indulge every note, every instrument, vocals, the in-hailing of the signer, the fretting of a cord; every detail counts. I often appreciated a background noise, someone talking in the background, a child screaming in the distance, or someone making an unwanted noise during a recording. The song would play seemingly flawlessly on other systems, while on mine, by boosting certain frequencies pertinent to the parasite, I could hear it. To me, the flaw is a rare treat. OK, often to devolve the flaw, the EQ must be grossly distorted, where the song becomes unpleasant. On the other hand, by manipulating the EQ at precise timing, the flaw rather becomes enjoyably part of the song. This is only a random example of "on-the-fly EQ" benefits. Everyone has a different hearing curve; and so do the musicians and recording engineers. So, if you think that you are an audiophile because you restrict yourself to flat reproduction, you are only chest inflating yourself by labling yourself a purist; sorry to inform you that you are no different than any other, you too have a different hearing curve. So if you listen to flat, you are not even hearing the EQ the recording engineer programmed according to his hearing preferences. This is why I do not care for so called flat music. I love the highs and will take the lows that comes with them, because life on a flat line is boring.
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Old 13th August 2014, 08:58 PM   #26
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Quote:
Originally Posted by benphysics View Post
I'm 63 and have been an audio enthusiast since I was about 12. I can never get enough in every aspect. I've invested hundreds of thousands $ in audio equipment, commercial and DIY components. I ended up going DIY all the way since I was 30ish, for no commercial products were good enough or they were simply prohibitively expensive even in my standards. I was able to do much better DIY for a ridiculously small fraction of the money. I indulge every note, every instrument, vocals, the in-hailing of the signer, the fretting of a cord; every detail counts. I often appreciated a background noise, someone talking in the background, a child screaming in the distance, or someone making an unwanted noise during a recording. The song would play seemingly flawlessly on other systems, while on mine, by boosting certain frequencies pertinent to the parasite, I could hear it. To me, the flaw is a rare treat. OK, often to devolve the flaw, the EQ must be grossly distorted, where the song becomes unpleasant. On the other hand, by manipulating the EQ at precise timing, the flaw rather becomes enjoyably part of the song. This is only a random example of "on-the-fly EQ" benefits. Everyone has a different hearing curve; and so do the musicians and recording engineers. So, if you think that you are an audiophile because you restrict yourself to flat reproduction, you are only chest inflating yourself by labling yourself a purist; sorry to inform you that you are no different than any other, you too have a different hearing curve. So if you listen to flat, you are not even hearing the EQ the recording engineer programmed according to his hearing preferences. This is why I do not care for so called flat music. I love the highs and will take the lows that comes with them, because life on a flat line is boring.
Agreed. Many speakers and rooms may have problems that make turning up the bass or treble sound worse, but it's not usually the fault of the tone controls.

Room acoustics are often pretty bad, especially in the 80HZ - 300HZ range, which makes bass sound "boomy". Many tweeters are used at frequencies that they can't do well (below about 4kHZ depending on the crossover slopes). Turning up the treble can make this audibly worse. Some tweeters just have very ugly FR's at the high end that are made more prominent when the treble is jacked.

The Baxandall topology works great for me, and with one more part added (a cap) the conventional circuit becomes a low-Q bandpass adjustment, so you could have more than 4 sections if you want. Some Engineers think "Shelving" topologies are better. Shelving may have it's place, but I like the idea of avoiding any abrupt changes in the FR, which I feel can draw attention or significantly "color" the music. The Baxandall variable slope seems best to me.

I think the Duncan audio website (if it's still there) has a free computer thing where you can modify their default values of a Baxandall topology, and it shows you the min, max, and controls centered FR virtually in real time. To see the bandpass results I think I had to use a free SPICE program. I don't think Duncan had that option. Use all tight tolerance but cheap polypropylene caps, 1% metal film resistors, OPA2134 dual opamps and you'll be talkin' Hi-Fi goodness.
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Old 13th August 2014, 09:00 PM   #27
AuroraB is offline AuroraB  Norway
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I agree that there are some inherent flaws in the reasoning around the "no tone control" way of thinking, probably based on several ideas, - one being that there should be no more active elements than necesseary, another being the many badly designed tone and loudness controls of the 60s and 70s. The loudness curve of hearing is well established and understood, and I think noone disputes that. If your average listening level is reasonably high, the deviation from the lodness curve may not be large, but these high levels are not possible for everyone, so in that context, a proper loudness compensation could be very useful.

I probably have around 1000 LPs and somewhere thereabouts for CDs. The rather silly notion that the productions are tonally flawless, and therefor should not be altered, is of course not true. Those of us with acoustic live concert experience, be it symphonic, chamber, brass bands etc etc, somehow have an idea of how the music should sound, but for electronic productions, we don't have a clue, do we? Neither do we know how that production room did sound. Some of my records, quite a few actully. are undisputedly tonally flawed, and could do with some corrections. Previously I was also engaged in spare time activities that needed listening to various amateur recordings that desperately needed som "fixing".

There really are no problems with properly designed controls - just make them switchable! Oh - sorry - I forgot that switches are also a absolute no-no..... and in another thread here, even solder joints add distortion....... Nails and rivets, anyone??

Excellent designs for both tone controls have been made,and schematics should be availble. The fancy multitap pots used in some of these designs are not, I guess.
Someone up for a DSP design?..... I'm too od for that s*?t.... :-)
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