This article was originally in 3 parts.

PART 1

Adjusting the volume is the single most frequently used functionality in any audio system. That’s always the case, whether your system is an elaborate chain of several electronics or consists of just a cell phone and earbuds. Not only that, and this is something not many people know, but the volume control is one of the worse things to affect the sound quality of your system.

A volume control always hurts. You can’t completely avoid its damaging effect on sound reproduction no matter who designed or built it. It may be hard to understand how a device performing such a simple task can cause such harm, but the reason can be easily explained.

When we think of a volume control, most of us tend to see it as something that adds sound pressure to the silence. Most of us see zero as the default volume. In our understanding of how a volume control works, silence is the starting point. And it’s a misunderstanding stemming from the way we use the knob or buttons to control the volume.

In reality, a volume control works exactly in the opposite manner. Instead of adding to the silence, you are subtracting from the full blast. That ear-deafening maximum output level, which you’ll experience when you turn the volume knob all the way up, is actually not the end, but the starting point. 100%, not 0, is the default volume level. And the job of whatever volume device employed by the electronic is to reduce the output. In this sense, a volume control is a limiter, like the gate of a dam that limits the water flow. Just as the gate doesn’t supply any water, a volume control doesn’t supply any sound pressure. It only controls its flow (hence the term volume “control”).

This core principle is counterintuitive to most consumers because of the way these volume knobs and buttons are designed for real world usage—that is, we start from zero, or very little output, and gradually add volume, which is the exact opposite of how it actually works behind the curtain. It’s no surprise that volume controls are designed that way; otherwise, manufacturers would face a barrage of lawsuits for blown eardrums.

Now, what does this have to do with sound quality? To understand the correlation between the volume control and sound quality, all you need to know is this: the lower the volume, the harder the volume device has to work. To use my previous metaphor, the gate must work harder to keep more water in and let less water out. Conversely, the device would be doing nothing when the volume was not reduced at all (i.e., set to 100%). This is when the volume control would cause zero harm to the signal.

Which means the quality of the volume control matters more when the volume is low than when it’s high. Just think of how you’re using the volume knob on your preamp, integrated amp or receiver. If you’re using less than half its full range, which is how most of us listen, that means you are limiting more than half of the flow. This is hard work for the device. So, inevitably, something’s gotta give—in this case, sound quality.

But not all volume controls are created equal. Some damage the signal less than others. This is how a volume control becomes an important factor in the overall sound quality of an audio component and perhaps in the purchasing of one. if you want, you can test the impact a volume control has on playback sound by using the crappiest of them all—the one in your Windows computer.

To do so, simply connect your computer to an integrated amp or a receiver from a reputable audio manufacturer likely to have equipped the product with a decent volume control. Then, listen to music by controlling the volume only on the amp while the computer volume is set to 100%. Then do the opposite, where you adjust the output level by using only the computer’s volume control while the amp’s volume is turned all the way up (*). A typical digital volume control on a computer is the worst kind, so the second setup should sound considerably worse than the first.

But many people don’t consider a computer a “real” audio component. So, how about the quality of the volume control on a typical audio component from a reputable audio brand? And can it be heard separately? In other words, can the impact of the volume device be heard separately from that of all the other parts inside the unit? And here’s a more imaginative question: knowing that every volume control, no matter how well designed or expensive it is, always harms the sound to some extent, what would an audio system sound like if there was no volume control at all in the chain? Would it be as glorious as the theory seems to promise?

Well, if you’re curious, you’re in luck, because I devised ways to conduct such tests without dismantling a unit or destroying my eardrums. In my next article, I’ll report back on:

• When we change where (=on what device) and how we control the volume, what’s the impact on the sound quality of an audio system?
• How does the same audio system sound when there is no volume control in the chain whatsoever?

I heard the results and they are enlightening to say the least!

* Caution: Start from a very low volume on the computer so you don’t accidentally blow your system’s speakers.

PART 2

Riddle me this:

• How do different types of volume controls impact the sound quality?
• In an audio system devoid of a volume control—analog or digital, active or passive—how does the system sound in comparison to one equipped with a volume control?

Those are the questions I’ll attempt to answer in this 3-part series. In Part 1, I explained how a typical volume control works and affects sound quality. For this part and the concluding Part 3, I performed three AB listening tests designed to get us closer to the answers. The tests include the following comparisons:

1. A Good Digital Volume Control vs. A Good Analog One
2. A Good Analog Volume Control vs. Another Good Analog One
3. The Winner from the Above vs. No Volume Control
   

Now, on with the show!

  Test 1: Volume Controls: Digital vs. Analog

This test compares the following 2 system configurations:

Config. 1 (A Digital Volume in Use): A Wyred4Sound DAC2 connected to a Densen DM-30 power amp where the volume was controlled in the digital domain by the DAC

Config. 2 (An Analogue Volume in Use): A passive volume control inserted between the same DAC and amp where the volume was controlled in the analog domain by the passive device

It was imperative for this test that I use a passive volume device—using a typical preamp’s volume control would have muddied the waters because then the entire preamp would have imparted its character on the sound. Instead, I used a passive device called the Placette Audio Remote Volume Control—basically, an outboard volume control.

My conclusion was crystal clear. The Placette’s analog volume control trumped the DAC’s digital one. When the volume was entirely controlled by the Placette, with the DAC’s digital volume fixed at 100% (i.e., not used), the music sounded significantly more fleshed out and took on a more organic quality. All these benefits came without any compromise on transparency.

This result surprised me because of how good the DAC-Amp combo sounds. Moreover, I was barely using the digital volume, staying in the 50-60 volume range from the 70 attenuation steps available. As I mentioned in Part 1, the less the volume is lowered, the less it should, all else being equal, affect sound quality. It stood to reason, then, that the 32-bit Wyred4Sound’s digital volume would have been as near to lossless as possible, making this DAC-Amp combo a tough act to beat. But as they say: you don’t know what you don’t know.

A few words about the Placette Audio Remote Volume Control. It has an almost religious-like following among seasoned audio enthusiasts. It’s a product that does only one thing—volume attenuation. Heck, it doesn’t even have an input selector. Yet Guy Hammel, the gentleman who builds and sells it direct from his company website, asks $1,295 for it. I had my doubts prior to trying it in my system. But since these tests, I feel compelled to tell as many people as possible about it, and you’ll see why in Part 3.

By the way, I’m not claiming that this test proves that an analog volume control is always better than a digital one. After all, I was only comparing two implementations, one from each category. But it does confirm that you can significantly improve the sound quality of a system simply by changing where and how the volume is controlled.

Test 2: Volume Controls: Analog vs. Analog

For this test, the Placette was inserted between a a Schitt Modi DAC with no volume control and a Creek Evolution 2 integrated amplifier. In this setup, I could compare the Creek Evolution 2’s internal analog volume control to an external one, the Placette. Note that the Placette costs more than the entire integrated amp ($1,295 vs $1,200). Compared to the Creek, you could say the Placette might, on the surface, seem akin to a wedding singer who can sing only one song yet demands a higher fee. I still ended up hiring her, because… well, you’ll know why in Part 3.

The comparison was made between the following 2 modes:

a) The amp controlling the volume, with the passive device’s volume fixed at 100%

b) The passive device controlling the volume, with the amp’s volume fixed at 100%

The result? This time, the difference wasn’t as pronounced. I had to go back and forth a few times between the two modes to draw a conclusion. But a conclusion I did draw: music sounded better with the Placette controlling the volume. But unlike in the first test, where the improvements I heard came in the form of a more organic and fleshed out presentation, here I heard improvements in transparency and clarity. So, yes, an improvement can be had from going from one well-made analog volume control to another, but predicting which will sound best? Not so easy, although, again, I was struck by how well the Placette did its job.

And now for the big question—how would an audio system sound if it used no volume control whatsoever?

PART 3

There’s a sentence I often come across in product reviews, blogs or forum posts, and it’s: “It’s all about the music”.

But is it? For me, it’s not just about the music. There are so many other aspects to this hobby that I enjoy. And one of them is that, in this hobby, a mere consumer often takes on the role of a creator. It’s about assembling multiple parts to create something that’s greater than the sum of those parts.

To create something, one has to start by being curious. “What if I do this? What if I do that?” The result aside, there’s a kick to be had in the process of asking those questions and getting answers. And even if an answer isn’t what we hoped for, it still puts us ahead of where we started. It’s what defines our underlying approach to our hobby—the journey. And it’s what differentiates us from the typical music lover who buys audio products because “it’s all about the music”.

In Part 2, I reported on two of the three AB listening tests designed to highlight the differences between volume controls and their effect on the sound. They were:

Test 1. A Digital Volume Control vs. An Analog One

Test 2. An Analog Volume Control vs. Another Analog One

Those tests established that the volume control on the Placette passive device was the champion among all volume attenuation tools available to me. I spent a lot of time listening to a few different setups with the Placette in charge of controlling the output level, and my experiences have been always positive. It fundamentally changed my whole system, to the point where I would say it has now become the heart of it.

But remember what we established in Part 1: every volume control hurts the sound quality—unless the volume is at 100%, a state where the volume control, which is a limiter by nature, doesn’t have to do any work because it’s not in use. Now, my question is, can the Placette, the winner of my short volume control shootout, compete against the god of all volume devices, a.k.a. No Volume Control? We’ll hopefully get an answer with our final…:

Test 3. An Excellent Analogue Volume Control (the winner from Test 2) vs. No Volume Control Whatsoever

For this test, I used the same three components used in Test 2. namely:

• A Schiit Modi DAC with no volume control

• A Creek Evolution 2 integrated amplifier
• A Placette Audio RVC passive volume control, placed between the other two components

For comparison purposes, I used the following two playback modes:

a) The Optimal But Practical one, wherein the passive Placette controls the volume, with the amp’s volume fixed at 100%

b) The Living Dangerously one, wherein the volume is fixed at 100% on both the amp and the passive device

The Living Dangerously mode is a sure-fire way to destroy both speakers and my eardrums… unless the music itself is very quiet. With that in mind, I used the Audacity audio editor to “remaster” my test track* to an extremely low level. That way, even with the system blasting out at full volume, the sound would be harmless, to both my speakers and ears. Except that when I tried my new file on my system, it was still too loud, so I cut a new file by lowering the level even further. For the Optimal But Practical mode, I played my test track in its original form, i.e. not the one I “remastered”, and used the Placette to control the volume. To perform the same tests in your system, you can download all three files here.

The result? This time, the difference was so dramatic that I didn’t need a second listen. The Living Dangerously mode was superior in every respect. It had more focus and body. It sounded larger, yet more intimate. It accomplished a lot more without giving anything up.

That made me curious to see if I could improve the sound even more. I removed the Placette from the chain altogether, and connected the DAC directly to the “Direct AV” input of the Creek amp, thereby bypassing not only the volume control but the Creek’s entire preamp section—call it the Living Insanely mode. Using the Creek as a power amp, I heard the same benefits to the sound as I did from the Living Dangerously mode, but more of all of it. This caused me consternation: how could I go back to living in the normal audio world of using a volume control when I had had a taste of a world with no volume control? But I couldn’t constantly live dangerously and get away with it, could I?

*

These tests took a lot of my time and energy to set up and conduct. But I’m glad I did. They showed me the extent to which volume controls can degrade the sound. But they also showed me that not all volume devices are created equal—of the volume controls I tried, the Placette passive volume control was the one that got out of the way of the music the most. Nothing, however, could beat having no volume control in the signal path to obstruct the sound.

All of this has made me curious to try something else—drive my Prius with the breaks taken out to see if it can run like a Ferrari.

*A single-file collage of the first 30 to 50 seconds of 3 recordings, including Dave Brubeck’s “Take 5”, Chopin’s “Etude in C major” played by Murray Perahia, and a live version of the Eagles’s “Hotel California”.