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Tone, balance, mono/stereo and filter controls - sadly missed

Pluto

New member
Mail me

Mail me

...obtain a test recording in mono of say a human voice intentionally placed in the exact middle of the channel and then to set the balance to locate this voice dead center
PM me with an external e-mail address and I'll send you some suitable test material. It will be in MP3 format but that will make no difference for your intended purpose.
 

mhennessy

Member
Use mono tuner?

Use mono tuner?

Or if you have a tuner connected to your system, you should be able to switch it into mono.
 

Pluto

New member
Channel match?

Channel match?

if you have a tuner connected to your system, you should be able to switch it into mono.
There is, however, no guarantee that the level of the two legs is matched well enough to use in a quasi-test role.
 

mhennessy

Member
Level and image shifting

Level and image shifting

There is, however, no guarantee that the level of the two legs is matched well enough to use in a quasi-test role.
Certainly anything is possible, but have you come across a tuner that had a significant channel mismatch? I haven't. I guess that I've measured between 20 and 30 tuners in recent years - not a massive sample, admittedly, but I've no reason to suspect that tuners are any worse than CD players or sound cards (one of the latter two will of course be used to play back the file you've kindly emailed). In general, I'm usually quite impressed with domestic gear from the big manufacturers.

Given that 0.5dB is about 5% in voltage terms, errors are very easy to measure. Gains of amplifying stages are determined with 1% resistors in decent gear, and because of the way statistics work, the likely overall error reduces as you include more stages. As an aside, Douglas Self that explained this trick with his Precision Preamplifier '96 - he used five 1% capacitors in parallel to make an otherwise unobtainable large capacitor with 0.44% tolerance. Perhaps Alan does similar things in his crossovers?

Actually, when you measure resistors made in the last ~25 years, they are surprisingly close to their stated value - it's rarely worth paying the premium for 0.5% or 0.1% resistors if you don't mind doing some selection - indeed the last batch of 0.5% Welwyn RC55D resistors I bought were comfortably better than 0.1%, which saved me a small fortune at the time. Welwyn make the RC55 in 1%, 0.5%, 0.25%, 0.1% and 0.05% - almost certainly they all come off the same production line, where the aim is to make them to the finest tolerance, and the tolerance which is marked on is according to measurement, and market demand.

What tends to cause channel mismatches are volume potentiometers, especially at low levels. These can easily be 2 or 3dB.

One thing I learnt a while back was that channels do have to be matched surprisingly well. Ages ago I built a preamp that used the PGA2310 volume control IC that can change gain in 0.5dB steps. I decided that 1dB steps were OK for the main volume control, but when I wrote the code for the balance function, that did change in 0.5dB steps. But I found that a 0.5dB gain change in one channel moves the image by about 15% - in other words, with loudspeakers placed about 7 feet apart, a central voice moved approximately 1 foot away from the centre. Next time, I'll use a separate IC with finer steps for the balance function.

And this is why I always begin a loudspeaker assessment by listening in mono and judging the width of the central mono image - this tells you how well matched they are. It's a very tough test - and you always find that on all but the best, different parts of the frequency spectrum are in slightly different parts of the sound-stage, as the errors between loudspeakers are very frequency-dependent.

Interestingly, we have a pair of 'speakers at work - I won't name them - that seem to have a very exciting stereo image, especially with pop recordings. But when you press the mono button, the stereo image is just as wide! Obviously they are faulty in some way - we've taken them apart and done some basic checks, but can't find any obvious faults - the next step is to make some acoustic measurements on the drive units (one day...). But you could imagine the results if these were used to do a mix that was then played back on decent loudspeakers.

Cheers,

Mark
 

Pluto

New member
"Huge" just isn't big enough any more

"Huge" just isn't big enough any more

Certainly anything is possible, but have you come across a tuner that had a significant channel mismatch?
Yes - I had a tuner that was out of true by about 1.5dB and it annoyed the hell out of me for about a year until I finally sorted it out - a resistor that was not what it claimed on the coloured bands. It was particularly annoying to fix because, by that time, everyone was turning the pilot on all the time, regardless of content.

we have a pair of 'speakers at work - I won't name them - that seem to have a very exciting stereo image
Your comments about imaging are highly relevant these days, where 'sound stage' appears to have become some kind of holy grail with the goal of ever-increasing width. Writers appear to be seeking the linguistic means to describe an increase over last month's "massive", "gigantic", "colossal", "immense" superlatives attributed to one speaker or another.

One can only wonder how wide a stage some of these speakers exhibit when playing in mono!
 

mhennessy

Member
Channel imbalance due to component errors

Channel imbalance due to component errors

Yes - I had a tuner that was out of true by about 1.5dB and it annoyed the hell out of me for about a year until I finally sorted it out - a resistor that was not what it claimed on the coloured bands. It was particularly annoying to fix because, by that time, everyone was turning the pilot on all the time, regardless of content.
Ouch!

Well done for finding it. In general, metal or carbon film resistors are pretty good, especially when they lead a quiet life. Older carbon-composition resistors are a different matter entirely, and all will be high by now - normally well outside of their stated tolerance. All my hi-fi gear is new enough to use film resistors, but I do have quite a collection of older transistor (and occasional valve) radios that mostly use carbon-comp. All good fun!



Your comments about imaging are highly relevant these days, where 'sound stage' appears to have become some kind of holy grail with the goal of ever-increasing width. Writers appear to be seeking the linguistic means to describe an increase over last month's "massive", "gigantic", "colossal", "immense" superlatives attributed to one speaker or another.

One can only wonder how wide a stage some of these speakers exhibit when playing in mono!
Quite so. I think that "holographic" is one of my favourite adjectives. I've never really understood it - any deviation from a single horizontal plane between the loudspeakers is normally caused by problems with room acoustics or faults in the system. OK, there are the occasional recording that manage to go beyond that - for example, Amused To Death by Roger Waters, which uses Q-sound most effectively (perhaps not the most cheerful listen, but technically superb and well-worth seeking out if you haven't already got it).

All the best,

Mark
 

tedwin

New member
Tone controls on speakers?

Tone controls on speakers?

Just a thought on tone controls. Why don't you (Harbeth) give people the option of tone controls on the speaker? Wasn't it once fairly common to see a pair of knobs somewhere on a speaker to deal with room and placement issues?

This would also possibly open the subject to debate via high profile reviews (stereophile etc) maybe ultimately leading to us getting more options of amps with tone controls again :)
 
G

Gregl

Guest
No tone controls, no options

No tone controls, no options

I think this whole thread is awesome. What I don't understand is why somebody would have an audio system without balance and tone controls. It seems we are talking like we do not have any options for equipment that have them. If you are buying an audio system and don't have tone or balance controls I think that is really stupid. Why would you rely on every recording you own to be correct digital or analog.

There is still a lot of gear out there that has these options I use them everyday in fact I probably wouldn't listen to music at all if I didn't have them. Some recordings I own are so rolled off in the top and some have no bass whatsoever they aren't even listenable but with tone controls MAGIC !
 

Macjager

New member
Importance of EQ

Importance of EQ

Before I purchased my Harbeths, and came to this site, I really did not have a clear understanding of the difference between Audiophool reality and reality...Once I got my head adjusted to reality, and began to think and listen for myself, I realized that some of the controls that should exist did not.

At the time of audiophool reality I did not know better, and went with the advice of the "knowledgable ones"...Long story short, I purchased a studio grade (ie $215, not expensive at all!!) EQ, that gave me back the tone controls and the ability to adjust the balance on each channel. The unit does have a bypass, and I have used it to hear the difference between what I have adjusted on the EQ and how the sound comes out of the pre-amp ( I have a separate amp). I much prefer to use the EQ settings rather than the bypass, and frankly, I am quite satisfied that there is no interference that I can hear when the EQ and its settings are engaged. So, simply put, if you have an expensive amp/pre-amp or combination thereof without tone and balance controls, a studio EQ will probably give you more control than you ever thought you may need (I have 31 sliders on each channel!! - no, not a control freak at all)

cheers

George
 

broadsword

New member
The marketing of amplifiers

The marketing of amplifiers

This thread has been very enlightening. Should we distrust every modern amp manufacturer that does not provide us with tone and balance controls and a mono switch? Are they taking the minimalist stance because they agree that the "cleaner" signal path (as has been argued by Alan is more or less a myth) is better for us than the ability to tune the sound to our listening environment/taste, or because it's the current trend and helps them to sell most units to a gullible public? (and at the same time, reduce manufacturing costs a little).

It's staggering really the highly respected names that fall into this category : Naim for one.
 

Don Leman

Member
Responsible use of tone controls?

Responsible use of tone controls?

I'm old enough to remember when tone and loudness controls were quite common. Later graphic and parametric equalizers came into vogue. It was not uncommon at all to see the loudness control engaged even when the volume was at party levels to get more bass. Looking at the graphic equalizer settings most people used was a joke quite literally, as it resembled a smile.

I'm thinking it was not entirely a bad thing tone controls were removed.
 

Kumar Kane

New member
Wiring for mono?

Wiring for mono?

Is there a viable way to wire speakers to an amplifier in a way to get mono, as in getting both speakers to play both channels?
 

Pluto

New member
Probably not

Probably not

Is there a viable way to wire speakers to an amplifier in a way to get mono
The generalised answer is NO!

Depending upon the actual configuration of the power amp output stage, this might be possible in some cases but, unless you know exactly what you are doing, forget it.

BUT

to achieve quick and dirty mono, simply wiring the two amplifier inputs in parallel (and using a 'Y' adaptor is an easy way to achieve this) will often work well enough. For the next level of sophistication (!), combine the two channels via 4.7kΩ resistors.

Signal manipulation of this type must generally be done before the power amplifiers.
 

Kumar Kane

New member
Creating mono from CD player

Creating mono from CD player

to achieve quick and dirty mono, simply wiring the two amplifier inputs in parallel (and using a 'Y' adaptor is an easy way to achieve this) will often work well enough. For the next level of sophistication (!), combine the two channels via 4.7kΩ resistors.
If I were to connect both CDP analog outputs to both amplifier inputs, would this work? Why would this be "dirty"? Why would I need resistors?
 

Pluto

New member
For channel driving protection

For channel driving protection

If I were to connect both CDP analog outputs to both amplifier inputs, would this work?
Probably, but you will need to try it to find out. You may find that the overall level is rather lower than expected, in which case...

Why would this be "dirty"? Why would I need resistors?
Because each output will be attempting to drive the output impedance of the other. That output impedance ought to be very low (<100Ω) so you are asking a lot of an output stage which is designed to drive a load of, typically, ≥10kΩ. By adding the resistors (which ought to be physically at the amplifier end of the wiring, not by the CD player) you are partially isolating each output from the other.

A really well-designed output stage will not behave differently either way, but most will benefit from the addition of the resistors.
 

anonymous

New member
Parapsychology meets audiophilia

Parapsychology meets audiophilia

I came across this and thought it was of interest for this thread:

http://www.douglas-self.com/ampins/pseudo/subjectv.htm#5

All of the alleged effects listed below have received considerable affirmation in the audio press, to the point where some are treated as facts. The reality is that none of them has in the last fifteen years proved susceptible to objective confirmation. This sad record is perhaps equalled only by students of parapsychology. I hope that the brief statements below are considered fair by their proponents. If not I have no doubt I shall soon hear about it:

"Tone-controls cause an audible deterioration even when set to the flat position."

This is usually blamed on "phase-shift". At the time of writing, tone controls on a preamp badly damage its chances of street (or rather sitting-room) credibility, for no good reason. Tone-controls set to 'flat' cannot possibly contribute any extra phase-shift and must be inaudible. My view is that they are absolutely indispensable for correcting room acoustics, loudspeaker shortcomings, or tonal balance of the source material, and that a lot of people are suffering sub-optimal sound as a result of this fashion. It is now commonplace for audio critics to suggest that frequency-response inadequacies should be corrected by changing loudspeakers. This is an extraordinarily expensive way of avoiding tone-controls.
 

A.S.

Administrator
Staff member
Fine dining ... and tone adjustment

Fine dining ... and tone adjustment

I came across this and thought it was of interest for this thread:

http://www.douglas-self.com/ampins/pseudo/subjectv.htm#5
It's very interesting that a first class engineer like Doug Self and a rank amateur but careful listener like me are completely in step on the issue of tone controls.

As I said before, when the audio revolution comes, it will be those that advocated removal of tone controls and then tried to justify it to the great unwashed masses with gobbledygook BS bunkum that will be first against that wall. There cannot be a domestic listening room and/or recording and/or speaker type that would/could not benefit from the judicious use of a touch of tone adjustment here or there.

Tone controls are the salt and pepper of audio listening. No serious diner should kowtow a chef's personal belief that condiments should be banned from cuisine.
 

broadsword

New member
What is `loudness`

What is `loudness`

Related question: what does a button marked "Loudness" do? My Marantz amp has it, and it does sound more dynamic with it on - but it can't be just turning the loudness up surely?
 

A.S.

Administrator
Staff member
Related question: what does a button marked "Loudness" do? My Marantz amp has it, and it does sound more dynamic with it on - but it can't be just turning the loudness up surely?
Ok' good question. I`d suggest a little DIY experiment.

Turn off the loudness switch and turn the volume right down. How does it sound? My bet is that music will sound extremely middly with no bass at all. Don't touch the volume control but turn on the loudness compensation button. Sound more natural now at this low volume?
 
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