I need a loudness switch
mijostyn:"Tim, I’m all for the subs but since when is Class D the harbinger of good bass? Or good anything for that matter?" Hello mijostyn, I mentioned this on one of my earlier posts. Here’s a copy of what I stated on that post: " Yes, the old loudness controls boosted both the bass and treble to compensate for the Fletcher-Munson curve reality of human hearing. Strange, but this is also one of the 1st qualities I noticed with all the high quality class D amps I’ve owned. The bass, midrange and treble balance seemed to be properly balanced to me no matter the volume. YMMV? Not sure." This quality I clearly noticed very early on in listening to the first class D amp I ever used in my system, a Class D Audio SDS-440-CS stereo amp. At that time about 4-5 years ago, my system consisted of a VTL 2.5L preamp swapped out with a set of 4 NOS Mullard tubes, an Oppo 105 as a source for playback of CD/SACD discs with an attached Synology hard drive storage unit for hi-rez FLAC music file playback using the Oppo as a DAC and Magnepan 2.7QR speakers. I replaced my Aragon class AB stereo amp with the new class D stereo amp in my system and just let it warm up enough to become acclimated to the heated indoor temp on a winter day in Indiana before giving it a thorough tryout. I didn’t know what to expect at this point, playing the first few CD tracks, but was very curious and all ears. The second sound quality difference I clearly noticed was the lack of virtually all background noise to the point of being a bit startled when the first track began playing because the room was so quiet, as if I’d forgotten to press the Play button on the Oppo. The music seemed to just emerge from an inky black, dead-silent background that was quite impressive and that I believe was responsible for the third sound quality difference I clearly noticed, a very vivid presentation that had obviously increased detail levels but that sounded consistently smooth in the treble range with no hint of brightness or harshness. I believe the fourth sound quality difference that was clearly evident was the improved bass response which was more solid, powerful, detailed and dynamic than I had ever heard and felt my Magnepan 2.7Qrs perform up to that point. I didn’t know until then that these speakers were even capable of this level of bass performance. The complete story of my knowledge gained from my fairly consistent efforts to improve bass performance in my system and room do not end there with class D, however. I subsequently added an Audio Kinesis Debra 4-sub distributed bass array (DBA) system powered by a separate 1K watt class AB sub amp a few months later and realized by comparison that the deep bass sounded, of course, more powerful and dynamic because there were now 4 subs sharing the deep bass duties as opposed to only my pair of 2.7QRs previously. But what I wasn’t expecting was that the bass also sounded significantly more natural and real than with this system than the class D amp alone driving my 2.7QR speakers. I stiil ran the 2.7QRs full range down to their rated bass extension of 35 Hz but used a 40 Hz cutoff on the AK 4-sub DBA system so that they supplemented all bass reproduced between 20 and 40 Hz with an overlap between 35 and 40 Hz. I believe this was due to the class D amp having a much higher Damping Factor than the DBA class AB amp/control unit driving all 4 subs. By comparison,it seemed to me that the class D amp with 2.7QRs was truncating the deep bass notes’ natural decays. The AK Debra subs, all powered by a class AB amp with a much lower Damping Factor, seemed to reproduce the deep bass notes’ natural decays much more, ahem, naturally and completely without any noticeable truncation. The strange part is that I perceived the class D bass as sounding very good in power, dynamics and detail up until I heard the improved bass performance of the AK 4-sub DBA system. My point being that I believe many would be satisfied with the class D amps improved bass performance, even with the somewhat truncated deep bass notes’ decays, if they can’t afford the $3K for an AK Swarm or Debra 4-sub DBA system at the moment. As to the old loudness controls boosting both the bass and treble to compensate for the Fletcher-Munson curve reality of human hearing, this is also one of the initial qualities I noticed with all the high quality class D amps I’ve owned. The bass, midrange and treble balance seemed to be properly balanced to me no matter the volume. I remember noticing this when I decided to test out how loudly my first class D amp sounded when played at high volume, I would estimate I increased the volume slowly from zero up to a much higher volume than I would ever soberly listen to my music, which I’m estimating to be at least 120 dBs. I was amazed to discover that I perceived the relative balance between bass, midrange and treble remained remarkably consistent as I progressed from a volume level of zero all the way to about 120 dBs, which was excruciatingly loud but still lacked any sonic signs of clipping. I’ve clearly noticed the above qualities on all 3 class D amps I now own: the Class D Audio stereo SDS-440-CS amp I currently use to power my pair of rear surround speakers, the Emerald Physics stereo EP-101.2SE amp that I currently use in bridged mono mode to power my center channel speaker and the pair of D-Sonic monoblock M3-600-M amps I currently use to power my Magnepan 3.7i main speakers. I’ve personally experienced this ’built-in automatic loudness control’ quality not only on the class D amps I own but on numerous good quality class D amps I’ve listened to on other systems. I realize this seemingly universal quality of class D amps is rarely discussed but I perceive it so distinctly that I seriously doubt I’m the only individual that’s able to perceive it and assuming this circuitry even actually exists. As I understand it, class D power modules contain circuitry that constantly compares the inputted signal to the outputted signal and makes any necessary adjustments to the outputted signal before releasing the analog signal to the speakers. I believe this circuitry is called a comparator circuit and this would be the obvious circuitry choice to incorporate an automatic loudness control function into that would function according to a pre-coded algorithm. However, I think it’s important to note the above is only my theory based on my numerous class D amp listening experiences on a relatively small sample of the total currently available class D amps. I’m very interested to learn what leading class D amp designers would have to say about this quality and subject if asked. So as always, YMMV. Tim |
Wasn’t Loki the name of Ragnar’s troubled shipbuilder friend on the tv series Vikings? That guy was a bit quirky and the Schiit Loki apparently is capable of behaving similarly. Wait a minute, uh-oh. Now I remember, his name was Floki, not Loki. Oh well, with quotes like this:“The space between life and death, that’s where we are the most alive.” Floki “, it’s probably best it’s not named the Schiit Floki. scottht, You may find more relevant wisdom in another Vikings character’s quote: "Always remember to finish off your opponent, if you can. No man ever ran away with his entrails hanging to his knees, or his head cut off.” Rollo “ Perhaps your opponent is a lack of high quality bass in your system and room. Your ally/solution could be as simple as a good quality class D amp or a pair of good quality subs with a remote. Tim |
As Scott has noticed it is not easy to do this in the analog realm. It can only be right at one volume and analog filters can play havoc with things like imaging. For decades the best preamps avoided tone controls and loudness switches. None of us would give an equalizer a first look never mind a second one. But with digital this has changed in a big way. As long as the sampling rate and bit depth are up there the benefits far out weigh the detriments. Analog guys have a tendency to be digiphobes. I think this is unfortunate. |
Get a phono pre with a volume control that has extra gain or head room for your cartridge. I have a Parts Connextion modded PS Audio GCPH in a second system with a Soundsmith cartridge that works great together plenty of authority and detail and a remote to boost gain for thin recorded albums. I am breaking it down and selling of the gear if interested in the GCPH. |
Mike, if you look at the Fletcher Munson curves the boost in treble is pretty high up and is less noticeable than the bass boost which is in a part of the range that is very obvious. So you are right in that the obvious part of loudness correction is in the bass but if you could AB curves you would note that the curve with the treble boosted correctly sounded more natural. |
mijostyn: Yes, I’m aware that old loudness controls boosted both bass & treble, and that the F-M curves justify that. I read many years ago that the treble boost is questionable. I can’t remember where I read that, so I can’t cite a source. I will say, my subjective experience is that boosting the bass provides most of the benefit. My preamp has a treble control, & I’ve never felt the need to boost treble as volume decreases. |
Yes, the old loudness controls boosted both the bass and treble to compensate for the Fletcher-Munson curve reality of human hearing. Strange, but this is also one of the 1st qualities I noticed with all the high quality class D amps I've owned. The bass, midrange and treble balance seemed to be properly balanced to me no matter the volume. YMMV? Not sure. Tim |
Or you could try one of these, at no risk (cost).I second the Jolida unit I would not be without it now. Love the fact it actually has three inputs so all of my analog front ends are plugged into it, cassette and reel tape which on vintage units have notoriously low outputs to begin with. Now it does not boost treble as such, but the "wider image" dial can certainly give that impression. Yes you have to adjust the settings at times for different sources or albums but you would likely have to do that with a Loki or any tone control piece. Plenty of good reviews on the Black Ice and even a thread in this forum. https://forum.audiogon.com/discussions/jolida-black-ice-audio-foz-ss-x-sound-enhancement?highlight=j... |
Yes, the Loki would work. You would have to adjust it for every different volume so it would be cumbersome. You could also not construct accurate opposing filters to your hearing ( Fletcher- Munson Curves.) Not enough bands. The best solution is a continuous band digital equalizer programmed to follow the Fletcher Munson corrections with volume change. To my knowledge there is no equipment designed to do this at this time. The Tact 2.2X and the last TCS are the only units I know of that had this capability. Anthem and Trinnov should get on the ball. 20 years later and nobody has yet to match Radomir Bozevic's technology. Dynamic Loudness Compensation is a gas. No matter what volume you choose the music sounds exactly the same. It is all done in the digital domain at 192/48. There is no distortion, none. Analog is wonderful as long as you keep to the "strait wire with gain" principle. Every time you do something to the signal you add distortion. Not so in digital. You are just juggling numbers. |
"My god man, get a Schiit Loki!!!" I'm also looking for a similar solution as the OP and am wondering how would the 20Hz control on the Loki blend with speakers that only go down to 35-40Hz? My concern is getting a "single-note" bass unless they have implemented a nice slope which could help with the transition to higher frequencies. Any input from folks using the 20Hz control for boosting the bass would be helpful. |
I have considered the low 2.2 v output of the Soundsmith. I also have a Rega p6 that has a new Exact cart that I believe is like double the output of the Soundsmith. But I hate that Rega table and sound. The only way to try is swapping out the cartridges. I guess I should suck it up and hook up the nasty Rega and see what it does. |
It sounds like you want to hang on to your CJ gear and add something, but if you're open to some different components, I recently picked up a Vincent Audio SV 237 integrated amp. 150 WPC of solid state power for 8 ohms, the first 10 watts are Class A and the preamp section is tubed. It not only has a loudness button, but also... tone controls (which are defeatable)! After putting in a better tube in the preamp section, I'm really liking it. I read in one of the reviews on it that it boosts both bass _and_ treble. I've tried the loudness button and thought it sounded pretty good, but haven't done any extended listening in that manner, preferring to leave things flat. |
Or you could try one of these, at no risk (cost). https://www.musicdirect.com/accessories/Jolida-Foz-SS-X-Sound-Stage-Expander |
As noted by mijostyn, loudness compensation might be a good solution. The most noticeable effect of loudness compensation is to boost the bass at low volumes. The Schiit Loki is a 4-band, analog EQ that many audiophiles like. You might give one a try to see if a bass boost does the trick for youwhen you listen at low volumes. It’s only US$149. |
Hi Scott, Correct, you need loudness compensation. Our hearing is less sensitive to bass and treble at low volumes. https://en.wikipedia.org/wiki/Equal-loudness_contour. Older preamps had a "loudness" switch but it was only really accurate at one volume. Tact Audio made a unit with "Dynamic Loudness Compensation." It changed the compensation curve dependent on the volume and it worked great except it was very expensive and the company is out of business. The bargain basement way of doing it is with treble and bass tone controls. But, Audiophiles shunned these so most units do not have them anymore. What you are stuck with is the fact that every recording has it's correct volume. This depends on how it was mastered. You have to listen at the volume the music sounds correct until someone comes up with a digital processor that reintroduces Dynamic Loudness Compensation. |
