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Best loudness contour in the business?

B

Bob Chieldon

Active Member
I have to confess to liking a loudness button on an amp or receiver.

Not just for low level listening but to also to bring loud music to party spec.

I'm lucky in that i can listen to music quite loudly without neighbours to bother.

My favourite loudness contour is therefore not the Yamaha control, this is muc better suited to serious and classical listening.

In a sort of order then:

Sansui: From the 350a to the 9090 Sansui do a fantastic loudness contour which is very good at the "party started" effect.
Akai: 1020-1050-1200 fantastic contour but not quite as good as the sansui
Teac: AG5700 really good both for low level and party. between the sansui and the Akai
Pioneer: Various '50 and '80: great for listening, just a bit too polite for party mode
Kenwood: Too clean, more subtle than Pioneer
Marantz: 2xxx series various, bit wooly and boomy. too much upper bass emphasis for my taste for listening or party mode

What are your favourites?
 
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I used to have variable loudness/contour controls on my 1970s Marantz and McIntosh preamps. Hardly ever used them, but loved them when I did. Now I have an on/off loudness switch on my new McIntosh C22 preamp. It’s very good, but nothing like the subtle variable contour controls. I rarely use it, but at low volume it makes sense and doesn’t overwhelm or muddy the sound.
 
McIntosh C-26 Pre Amp has a loudness knob that you can dial in as much as needed. It is great. Set the amp a little above your normal listening level. Then add the loudness to reduce the volume for lower listening levels. Much better than having it tied to your volume knob with a pre set taper.
 
I modified the Loudness Contour on my Audio Research SP3-A1 : the original pot was dead, so it was the occacion !

OXn2Ob-my-SP3A1-and-D76.jpg


VlRLWb-CONTOUR-modification-by-BG-on-SP3A1-2.jpg


Smoother, deeper and much more progressive effect is now provided by this modification... Plus a conventional sense of operation of the pot !

T
 
@tubelectron you can’t just bomb in here and show a nice upgrade to the ARC contour by schematic and not tell us what sonic differences it is from stock. Knowing more might have us upgrading, too.

I say this because it is a great control in stock form for my systems using it with just a bit of activation for normal listening. I usually run the knob, noon is off, ccw adds contour at about 10:30-11:00 for just a bit of boost on both ends.
 
Blue Shadow said:
@tubelectron you can’t just bomb in here and show a nice upgrade to the ARC contour by schematic and not tell us what sonic differences it is from stock. Knowing more might have us upgrading, too.

I say this because it is a great control in stock form for my systems using it with just a bit of activation for normal listening. I usually run the knob, noon is off, ccw adds contour at about 10:30-11:00 for just a bit of boost on both ends.
Click to expand...

Yes. First important point, @Blue Shadow : the original Loudness CONTOUR pot of my SP3A1 was cut on one section (I re-read my notes), so it was not working properly - at least on one channel.

* That said, here's what I observed with the original contour circuit as is :

1 - the sense of operation of the contour pot is not conventional, but this is the normal operation of that control, according to the SP3A1 manual : minimum contour = maxed pot. You back the pot setting to allow contour effect. This is not my taste, but if it had worked correctly as is, I probably would not have modified it.

2 - when maxed, the contour is roughly neutral, but with a significant and constant drop in volume, compared to TONE off.

3 - backing the pot setting increases the contour effect as expected, but only once the noon setting was reached. From full CW rotation back to noon, there's no noticeable effect, except the constant loss of volume (as mentioned in 2 - )

4 - once noon reached and going CCW : the contour effect appears and increases, but around 9:00, the effect becomes too heavy in the bass and doesn't change too much further. Roughly, the useable section of the contour pot as is is from 9:00 to 12:00.

* Given that the original pot was damaged, I took the occasion to cure and modify the contour control :

1 - shifting the control to normal sense of operation : maximum contour = maxed pot.

2 - nulling the volume drop when the control is zeroed, and absence of effect, compared to TONE off mode, allowing the use of the tone controls as if the contour was neutral or defeated. (820K additional resistor).

3 and 4 - regularly spreading the effect all along the travel of the pot, from no effect to max, and limiting the setting to the useful portion. (RV3A 2x 300K LIN instead of 2x 500K LIN).

5 - increasing the value of C20 from 100p to 150p 1% silver mica, to give a tad of brightness when contour is increased.

* What are the sonic results ?

- normal sense of operation : CW = incrrease of the effect. More practical to me...
- contour effect defeated when zeroed : no loss of volume, no perceived effect (or negligible), leaving to the tone control all their possibility of action.
- easier and progressive control setting all along the travel of the pot.
- no setting-useless part of the travel of the pot.
- slightly better balance in the treble at high settings of the contour.

But please note again that the original (OEM) control of my SP3A1 was not working as it should have worked, since the contour RV3A pot was damaged... So before attempting anything, compare your undamaged contour control operation versus what I described, to see if it's worth for you to modify your stock-working SP3A1 !

T
 
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Bob Chieldon said:
I have to confess to liking a loudness button on an amp or receiver.

Not just for low level listening but to also to bring loud music to party spec.

I'm lucky in that i can listen to music quite loudly without neighbours to bother.
Click to expand...
I have liked them, too, but for me it really is just for low level listening. I've been an apartment or rent-a-room dweller since 2006, so my listening level is always at about a 50 dB average with peaks up around 60 dB.
Bob Chieldon said:
My favourite loudness contour is therefore not the Yamaha control, this is muc better suited to serious and classical listening.
Click to expand...
I haven't owned the Yamaha, but I'd like to someday. My last amplifier with a loudness switch was a Marantz PM5004 integrated amplifier, and it worked very well for me. At present, I have a Rotel A11 Tribute. It does not have anything labeled as a loudness switch, but it does offer a couple of perhaps similar options which they call Rotel Boost and Rotel Max. I don't really like either one, and they're made less useful by not being able to be combined with tone control adjustments.

The tone controls themselves, however work fine, and, like Kwayde, I'm getting better results just using those. Dynaco once wrote, "A separate loudness switch is neither necessary nor provided in the PAT-5, for it is easy to preset the bass and treble controls to supply the loudness compensation to suit your needs." I haven't found that to be true with every amplifier or preamplifier I've owned (some tone controls have just been too subtle), but it is my best option on the Rotel.
 
I have a Yamaha receiver . The loudness pot is certainly more versatile than the single button style, but I rarely use it. It takes away too much midrange and makes the music muddy, to my ears.
 
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A second vote for vintge McIntosh:

Not only was the loudness contour tied to the volume knob, it also had a vaiable (second control) that allowed you to tailor it to the efficiency (sensitivity) of the speakers and the rest of the system. Most loudness controls didn't allow for more or less sensitve speakers and some didn't even have a gain pot added to the Volume control.
 
Bob Chieldon said:
I have to confess to liking a loudness button on an amp or receiver.

Not just for low level listening but to also to bring loud music to party spec.

I'm lucky in that i can listen to music quite loudly without neighbours to bother.

My favourite loudness contour is therefore not the Yamaha control, this is muc better suited to serious and classical listening.

In a sort of order then:

Sansui: From the 350a to the 9090 Sansui do a fantastic loudness contour which is very good at the "party started" effect.
Akai: 1020-1050-1200 fantastic contour but not quite as good as the sansui
Teac: AG5700 really good both for low level and party. between the sansui and the Akai
Pioneer: Various '50 and '80: great for listening, just a bit too polite for party mode
Kenwood: Too clean, more subtle than Pioneer
Marantz: 2xxx series various, bit wooly and boomy. too much upper bass emphasis for my taste for listening or party mode

What are your favourites?
Click to expand...

Always liked the loudness control on the Nakamichi 410 preamp. You set the volume at the highest setting you would listen to and then use the loudness as a variable volume control to attenuate signal while boosting highs and lows. Slick and good sounding implementation.
 
Bob Chieldon said:
I have to confess to liking a loudness button on an amp or receiver.

Not just for low level listening but to also to bring loud music to party spec.

I'm lucky in that i can listen to music quite loudly without neighbours to bother.

My favourite loudness contour is therefore not the Yamaha control, this is muc better suited to serious and classical listening.

In a sort of order then:

Sansui: From the 350a to the 9090 Sansui do a fantastic loudness contour which is very good at the "party started" effect.
Akai: 1020-1050-1200 fantastic contour but not quite as good as the sansui
Teac: AG5700 really good both for low level and party. between the sansui and the Akai
Pioneer: Various '50 and '80: great for listening, just a bit too polite for party mode
Kenwood: Too clean, more subtle than Pioneer
Marantz: 2xxx series various, bit wooly and boomy. too much upper bass emphasis for my taste for listening or party mode

What are your favourites?
Click to expand...
The best units don't need loudness boost (save for severely low volume). The best sound as good at low volume as they do cranked to loud volumes. Also, I need a unit which can be listened to seriously and be fun when desired. Older Sansui for me does this job (but it's got to be Cap Coupled), likewise Early Sony pre-1973.
 
My favorite implementations use a variable loudness dial instead of a one-size-fits-all loudness button. The best loudness contour I've heard is from a Nakamichi SR-4A Stasis Receiver. It's pretty incredible when dialed-in just right. The worst I've heard are from old cap-coupled receivers that haven't been recapped yet. The loudness button on those introduces syrupy thick, overpowering one-note bass that muddies the sound. Even when recapped though, I still don't like using the loudness button on those as the contour always sounds a bit too exaggerated or "off".
 
A loudness control was pretty common on receivers and integrated amps back in the day, mainly because of the combination of lower power, less dynamic range, lower resolution recordings, etc. I used it often in my systems through the 70's and 80's. For the most part, loudness control has become unneeded and obsolete in most modern audio systems.
 
I think the main reason "loudness" was used is because our ears are less sensitive to certain frequencies at lower volumes to maintain what would be considered a "flat" presentation as according to the human ear which does not perceive linear sound linearly, but instead perceives dips and peaks heard at certain frequencies from this linear information. Even new equipment measuring as perfectly flat/ linear can benefit from loudness as according to the Fletcher-Munson curves. At lower levels, it makes music sound more realistic, satisfying, and full. This, despite the fact it's technically a deviation or departure from true linearity many strive to achieve with their sound systems. At the same time, a truly high-end system often does not leave people "wanting" more or something better with a slightly different, non-linear FR curve, and that's ok too. It really just depends on what people like and prefer.

There are other methods to achieve something similar as mentioned using tone controls or an equalizer. I use a mastering processor/eq and target better [general] linearity first (within the listening room itself whose irregular shape and wall reflections also cause deviation from true linearity to begin with). This is done through room correction using rta. Then, I apply a very slight Fletcher-Munson curve on top of that. There are many different ways of achieving something similar.
 
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