Lasting Impressions: Manley VoxBox

PLEASE NOTE: This article has been archived. It first appeared on in July 1998, contributed by then Editor-in-Chief Rip Rowan. We will not be making any updates to the article. Please visit the home page for our latest content. Thank you!

It was with deep regret and sorrow that I returned the VoxBox unit sent to me by Manley Labs for evaluation.

How deep, you might ask.

Well, I considered selling my car or my furniture to keep it. How deep is that?

The VoxBox is not your run-of-the-mill voice processor. At $4000 it is beyond the reach of many of our readers. However, in our recent survey, I discovered that the average investment our readers have made in equipment is $30K, and that 45% of them consider themselves music professionals.

Then let me say that if you are a music professional willing to invest $30K in recording equipment, you should seriously consider buying a Manley VoxBox.

I used to wonder about the relative importance of a mic preamp in the grand scheme of things. After all, the mic is a flimsy diaphragm vibrating in air. Surely that’s the most important factor in recording. And there’s the media: analog media has limited headroom until you move to 30 ips 2″ tape, and digital media can sound grainy if you have poor converters. Compared to these two devices, the mic preamp couldn’t possibly alter the sound THAT much. Surely the mic preamp – a simple box with a gain knob – is just that – a simple box with a gain knob.

My priorities have been forever altered by the VoxBox. If I had $5000 to spend on a mic and a preamp, I would buy the $1000 mic and the $4000 preamp. Because I’ve now compared the alternatives and the results shocked me. I’ll clarify this point later in the article.

Just the Facts

The VoxBox is a 3-space unit built by Manley Labs in Chino CA. If you aren’t familiar with Manley then realize that Manley gear is readily found in all of the finest mastering and recording facilities in the world. Their equipment is usually best-in-class in whatever class in which it competes. The company has a no-nonsense, simpler-is-better, do-it-right-the-first time approach, and stands behind their products.

Voice multiprocessors are all the rage. The appeal is obvious: to get the most sound from the mic to the media, it pays to add a compressor, and EQ, and a limiter into the path. To keep things clean, let’s put these into a single box to minimize the connections and shorten the signal path.

Each manufacturer has its own take on what “should” be in a multiprocessor: compressors are the norm, then you get into EQ, limiting, de-essing, exciting, gating, A/D conversion, etc. The VoxBox competes with entries from Summit (MPC-100A), Calrec (RQP 3200), Inward Connections (Vac-Rac 4000) and Tube-Tec (MEC-1A). At $4000, the VoxBox is more expensive than these competing units, but it also offers more features – primarily the de-esser / limiter.

Front view: Manley Voxbox

The VoxBox is an all-tube mono unit containing an optocompressor, mic preamp, passive inductance EQ, and opto-de-esser / limiter. The design philosophy of this unit is like all of Manley’s gear: by using only the very highest quality components in the simplest possible configuration you will get the best possible sound. Its “compress before preamp” design is unique and is the result of an extremely quiet compressor design. The “simpler is better” philosophy means that there is only one amplifier in the system, whereas there would normally be four: mic preamp, compressor make-up, EQ op-amps, and de-esser / limiter make-up. This simple, short signal chain is capable of an inaudible noise floor at maximum gain, compression, and limiting. You can run it full-throttle with no audible noise.

Rear view: Manley Voxbox

The back of the VoxBox shows a block diagram of the chain, useful for making appropriate connections. The unit may be used in several ways. The recommended way is to record the signal out of the compressor / preamp (“Preamp Out”), and use the EQ / de-esser / limiter as an effect chain for processing the recorded signal. Alternatively, you can record the full signal path of compressor / preamp / EQ / limiter / de-esser (using the “EQ Out”).

Two stereo link jacks allows you to chain two VoxBoxes together to link the limiter and compressor so that they work together. All inputs and outputs are available as balanced XLR or unbalanced 1/4″ connections. The unit may also be used as a tube direct box / processor by using the unbalanced 1/4″ jack on the front of the unit. In short the VoxBox will integrate into whatever wiring scheme you prefer.

The construction of this unit leaves nothing to be desired. Top-quality military spec tubes are used in the amplifiers. Pots are smooth-feeling and have no discernible self-noise. Each component in the unit is the highest grade and individually tested (the parts in this thing are COVERED with QA check-offs and signatures – the mark of a company that diligently makes sure that each component is as good as it can be). The unbalanced outputs are transformerless, and the balanced outputs use custom-built output transformers. Choose your sound. The circuit board appears to be hand-soldered and has circuit lines that are unusually wide – about 2-4 mm thick – these puppies can handle some current! I was unable to see anything about the way this unit was built that was less than ideal.

Evaluation Approach

I evaluated the VoxBox over the course of a month, using three studios, a few engineers, and a number of microphones:

Studio One: Cakewalk 7.0 system using Digital Audio Lab’s Card D+ 16-bit converters. Dynamic mics: SM 57 / 58, AKG D1000, AT Pro 25A, AKG D100E. Condenser mics: AT 4050, AKG C-1000. Also used direct with bass guitar and electric guitar.

Studio Two: ACID system using Layla 20-bit converters. Used as a direct box for a bass guitar (no mics).

Studio Three: Logic Audio system using 16-bit ProTools. Condenser mics: Neumann M149, U87, AKG C414-BULS.

The unit was compared against a variety of preamps from the good to the bad and ugly, including the onboard preamps of a Mackie 1402, an Aphex 107, an ART ProMPA, a JoeMeek VC1, and a Drawmer 1962.


The optocompressor is a very sweet-sounding 3:1 compressor with variable attack, release, and threshold controls. The attack and release controls have five positions each and offer surprising control over the compressor. The “Fast” attack and release settings have the “fast compressor” feel, allowing the transients to pass but quickly compressing the signal. This and the “Med Fast” settings are great for instruments like guitar, bass, and drums. The “Medium” setting is slower, and less audible. As you move down to the “Med Slow” and “Slow” the sound is more like an engineer riding the faders. “Medium” and “Medium Slow” are good settings for vocals. I liked a “Medium” attack and a “Medium Slow” setting in particular for strong singers.

Compressor section

The compressor has a natural quality to it. It seemed to exhibit less treble reduction than I would have expected when driven into strong compression. In fact I recorded some loud guitars and snare drums with it with the compressor reducing better than 12 dbs and never got into sounds I didn’t like.

The best thing about this compressor for a voice processor is that it is unlikely to mess up your sound. Manley has provided a very gentle slope (3:1) and some intuitive controls that allow you to get generous levels of compression without overcompressing or changing the sound dramatically. This way, you can feel comfortable recording with the compressor on, and be satisfied that you aren’t making an unalterable mistake.


After the compressor comes the mic preamp. The preamp contains an input pad, gain selector, a phasing switch (that doubles as the mic / direct input connector), the Phantom power switch, and a selectable 120 / 80 Hz bass roll-off. By putting the preamp after the compressor, the unit optimizes the gain structure in order to fully utilize the dynamic range of the preamp – it’s just like putting a compressor on the signal before recording into your DAW to get the most out of the DAW’s dynamic range. This design is a killer. Expect to see this design in a lot more gear in the coming years. Also expect to see Manley win a handful of awards for coming up with this approach. It allows one to run the preamp right below clipping and get a fully tube-saturated sound.

Preamp section

First – a word about the “tube” sound. Having used a bit of tube gear, I had a certain preconception about what a tube amplifier should sound like. This unit changed those preconceptions for me. I don’t think I would call it “warm” in the traditional tube sense – although it is certainly not brittle – the VoxBox will NOT dramatically modify the sound of your song like the ART Pro MPA, the JoeMeek VC1 or a Bellari preamp. Turning it WAY up has the effect of adding a slight amount of tube limiting, until finally you get into some really harsh, buzzy distortion that I didn’t like.

However, I really loved the sound this preamp got when compressing the input and then running the preamp as hot as possible without distortion. It seemed to add a ton of energy that was otherwise lacking in other preamps. The fact that it never got particularly “warm” is fine with me, because to me that “warm” sound produced by the other preamps in this comparison is mushy on the low end and lacking in high-end definition – the clear sign of slurred transients. The VoxBox always sounded fast and hi-fi. But when driven hard, it would sound “hot’ or saturated, the sound of a great amp reacting strongly to the transients. Anyway….

I’m thinking that the folks at Manley have worked with me before, because they made the Phantom switch a locking toggle switch. This prevents me from my usual routine of (1) wondering why there’s no sound coming out of the mic, (2) realizing that the 48V power is off, (3) hitting the switch, and (4) replacing my tweeters after the 400 watt spike slams through my system. Of course there is an alternative: putting a safety circuit in the chain to auto-mute the signal when the phantom is turned on, but, of course, to do so would have required adding unwanted components into the pristine signal path. The simpler path is better – just prevent the engineer from hastily doing something regrettable.

The Gain switch bears closer examination. This is not an input pad. Rather, it controls the amount of negative feedback injected into the system. So what’s negative feedback? All amplifiers take the output signal, reverse the polarity, and inject a little bit back into the input side. This negative feedback loop reduces amplifier noise and produces a cleaner sound, but it also takes the “edge” off of transients – it makes the amp a little slower-responding. Manley has a winner with this control. By turning the Gain all the way up, the user reduces the negative feedback into the system. This creates a “hotter” sound with more “tube” sound – quicker to distort, more harmonics, faster transients. Turning the Gain down results in a cleaner, more controlled, “softer” sound. Change this knob, and you subtly change the sound of the preamp! How cool is that? For my purposes, we recorded almost exclusively with the Gain all the way up.

Pultec EQ

The EQ is a passive “Pultec” inductance EQ. “Pultec” means that this EQ is based on the design for the original EQ circuit designed for Ma Bell by Pulse Technology. This may have been my favorite section of the unit. Three controls allow bass boost, mid cut, and treble boost.

When I first realized that you could only boost the bass, cut the mids, and boost the treble, I thought, “Boo! Who built THAT?” I soon realized that I was underestimating this system. Half of the bass and treble frequencies overlap the mid-EQ, allowing for boosts throughout the spectrum – using the bass knob or treble knob – and cuts from 200 – 7000 Hz. This EQ works!

EQ section

On vocals, the mid cut section was useful for reducing the 3000KHz rise present in many vocal mics. The treble boost goes all the way out to 20 KHz and, BOY will it add sparkle. In the past when I’ve used a treble boost to add glistening-wet treble, all I got was crappy sibilance and a noisy, gritty high-end. With the VoxBox’s treble boost at 16K I was able to scoop out a generous heap of high-end WITHOUT EVER GETTING GRITTY. This treble boost is smooth and musical. Utterly the best EQ I have ever heard, period.

And did I mention the way those inductors sound on bass? The bass boost goes all the way down to 20 Hz. Set somewhere in the 35-70Hz region, boosts went from fat to FATTER to PHATTEST. We used this rig on a bass guitar that had old, rusted strings. The strings were intentionally that way – dead – because for this song the bass guitarist was trying to get a sound like Paul McCartney’s sound from “Silly Love Songs”. The tone we were going for was a big, round “plump.” With other EQs and amps, the string just sounded dead. With the VoxBox’s bass EQ, we were able to get the biggest, fattest bass sound you can imagine. Paul’s hair would have stood on end.

I thought, “this EQ is too cool” and decided to put it to the test. Earlier we had recorded vocals with the Neumann M149 tube mic. “Big deal,” I thought, “of course an M149 sounds great.” I decided to plug in an SM 58 and see how good I could make THAT sound. I plugged in the 58 and dialed around with the EQ. I quickly got the right EQ combination and I really couldn’t believe my ears.

I’m not going to tell you that the 58 sounded as good as the M149 – it didn’t. However, it’s the first time I have EVER heard a 58 on vocals in the studio producing a musically valid sound. Incredible. With this unit I could actually do a vocal take with a 58 and get a good, usable result. You don’t have to believe me – I would have called you a liar if you had told me that. Hearing is believing.

De-esser / Limiter

Next comes the de-esser / limiter. The de-esser is an opto unit like the compressor (except at a 10:1 ratio with very fast attack and release). It offers four de-essing frequencies – 3K, 6K, 9K, and 12K. Turning the frequency control to “LIMIT” eliminates the EQ from the path and causes it to function as a full-band limiter. Turning the threshold knob adjusts the treble reduction or lowers the output from the limiter.

De-esser / limiter section

This is a great feature that more preamps should have. On vocals, use this as a de-esser in conjunction with the treble boost. By carefully playing with the two controls you can add a ton of brilliance with the treble boost and actually reduce harsh treble frequencies with the de-esser. I dialed in a +6 db @ 16 KHz boost on the EQ and then reduced several dbs on the de-esser. The result was a silky-smooth high-end with lots of sparkle that never got harsh.

On instruments, use this as a limiter, allowing you to run the unit with more gain and without overdriving your A/D converter’s inputs. I used this on every track I recorded. The limiter is fast, but it isn’t a brickwall limiter. You can overshoot it. But it goes a long way towards keeping your signals within acceptable dynamic range.

Metering section

The last feature worth mentioning is the multifunction meter. The switch allows for monitoring gain reduction of the compressor (G-R), the input level on the line input (LINE IN) the preamp-chain output (PRE OUT), the master output (EQ OUT) and the gain reduction of the limiter / de-esser (D-S). With a quick switch-through of the knob, you can quickly see exactly what each section of the unit is doing. Since I am mostly concerned with the db level of my audio system’s inputs, and measure that with the software, I usually used this to get a handle on how much gain reduction I was getting from the compressor and the limiter.

OK, so that’s what it does. Now, how does it sound?

First of all, by putting a compressor first in the chain and a limiter last, with the preamp in between, it is possibly to dramatically increase the density of the recorded sound. When recording guitars I found myself setting the compressor for a moderate level of compression, cranking the preamp, and then limiting the output. This allowed me to drive the preamp hard without clipping my converter’s inputs. I love this concept. It really helped capture as much sound as possible into the 96 db dynamic range of 16 bit digital audio.

Second, the EQ is simply wonderful. This EQ is the simplest design possible: each control (bass, mid, treble) has only four parts in the signal path: a switch, a pot, an inductor, and a capacitor. I really can’t say enough about the EQ. On bass parts, the boost always has a round sound, no matter how much boost you dial in, indicative of high headroom.

Most importantly is the way the treble boost responds to sibilants and transients. Adding high-end on many EQs – like my Mackie – may boost the stated frequencies, but it also often produces distortion in the form of high-end harshness because the unit has poor components or such a complex design that it is unable to respond at high-speed, blurring the high-frequency sound and adding unwanted lower-order harmonics. Not the VoxBox EQ.


We used the VoxBox, of course, to record vocals. This is the intended use of the unit and that’s where it really shines. In my studio I do not have great vocal mics: I have a pair of AT 4050s, not usually recommended for vocal work, and access to a Rode Tube mic which I do not own. The 4050s have a well-deserved reputation for being harsh. They have a peak around 4K that can drive you nuts, especially with a sibilant singer. And they don’t have a rise in the treble, at about 10-12K, that really good vocal mics have which adds that magic sheen to the vocals that is just impossible to get by dialing in more treble at the console.

Or so I thought. I set up the VoxBox to record vocals with the 4050s. I dialed in about 2-3 dbs of mid cut at 3 or 4K, to compensate for the built-in rise inherent in the 4050. I took the treble out to 16K and added about 6 dbs of boost. I left the bass flat. Then I dialed in a slight amount of de-essing at 3K.

It parted my hair. I have configured other EQs and de-essers with this setting before, with average results. The VoxBox sounded perfect. I could not have wanted for a better sound. Unable to believe my ears I went back to my rig, and did some A/B tests. I recorded the VoxBox with the above settings, and then switched the EQ and de-esser out of the path. Recording “dry” I then went into my Waves NPP and tried vainly for about an hour to recreate the experience of the VoxBox with the Q2 digital paragraphic EQ and the C1+ de-esser. I was able to improve the sound – but the difference between the digitally processed signal and the VoxBox was very clear. There was no comparison to the detail in the high-end sparkle the VoxBox added.

We used the VoxBox to record some voice-over work in an advertising production house. This was the studio with the ProTools system, the Neumann mics and Drawmer preamps. The Neumann M149 is one of the best sounding mics ever made, and we did not find it necessary to add any EQ changes to the recorded sound. With the M149, the sound compared to the Drawmer unit was comparable. At that point we had reached the margin where I was unable to discern a significant difference between the preamps. They both sounded good. While the Manley’s compressor is smooth, the Drawmer’s is more flexible. I could have used either preamp with this fine mic.

The AKG 414-BULS was a different story. To me, the 414-BULS has a very similar sound to my AT 4050s. We used a little EQ on this mic and voila! brilliance added and harshness gone. The EQ made this mic sound better with the VoxBox than with the Drawmer 1962. For this application we also tried the JoeMeek. The JoeMeek was a different animal altogether. Frankly I did not like the sound of the JoeMeek on vocals, it seemed by comparison to be covered up.

We also tested the unit with the Neumann U87. The U87 doesn’t have the same sparkle that the M149 has. We found ourselves, again, reaching for a dab of the Manley EQ. And again, this is what set the VoxBox apart from other similar units. The sound tends to be always musical, and you never have to worry that adding a bit of EQ now is going to screw up your mix later. Everybody in the studio that day was amazed by the VoxBox on voice-overs.


Of course, the VoxBox is primarily intended for vocal work, but we’d be fools if we didn’t use it to record some instruments. We used this unit to record guitars, bass and drums with a variety of dynamic and condenser mics. The ability to overdrive the preamp with the unique compressor / preamp / limiter path made the guitars really pop when the strings were hit and growl with sustain.

Normally, I compress the living hell out of snare drums. Running in an all-digital environment, I usually record snare drums at about -6 (these things need room for error!) and then compress HARD after the fact. This gets a good sound, but it also means that I am amplifying the noise and really reducing the available bit depth. The VoxBox let me record snare drums and kick drums with a hard limiter that allowed the full snare sound to develop in the preamp and got a lot of sound onto the digital media. You can do that with any compressor / limiter. However, again, the unique configuration allowed me to drive the tube preamp hard, adding a little extra saturation.

How about using the unit with a C1000 condenser on hi-hats? I had a song that required a very clean-detailed hi-hat sound, and got it with this simple $200 mic and the VoxBox. Again, the right EQ was the magic trick.

We recorded bass guitar plugged straight into the front-panel 1/4″ input. This unit provides just enough gain to be used in this manner. Just turn it all the way up. I can hear you already – “if I turn it all the way up, what about the hiss?” To which I reply, “What hiss?” This unit sounds great and quiet at full gain. Just plug in your bass, turn the gain and input level all the way up, and let ‘er rip.

I was able to find a fault, finally. Using this as a direct box with a bass or electric guitar is great, but the unit does not have enough gain to overdrive the signal. Hey, this isn’t a distortion stomp box. Maybe I need to get a life. If your guitar or bass was particularly low-level, or if you want the sound of the Manley’s distortion (which I found unpleasant) you might want a little more gain than the VoxBox provides. Or just get a distortion or fuzz box. That, however, is the only fault I could find with this unit.

Lastly, we took the unit to Studio Two, where Bruce Richardson was working with Chuck Rainey on bass loops for an upcoming Chuck Rainey sample CD. We plugged Chuck into the VoxBox and turned it all the way up. We spent about 30 minutes searching for the right amount of compression, EQ, and limiting, and then started burning the bits.

What a sound we got. Chuck really made that box walk and talk. Chuck was playing a five-string Takamine bass, and when he hit the B-string the VoxBox would respond with a buttload of bass. We used a little mid cut to “darken” the sound the way a 15″ speaker would, then added a touch of hi-end to hear the string definition. Truly one of the best bass sounds I’ve ever heard.

Chuck likes playing over an amp, and the sound of a direct bass tends to bother him somewhat. Using the compressor, EQ and limiter tastefully we were able to really get the sound of a bass amp turned up. Outrageous. I’d have to say that for the bass player with a big budget, a Manley VoxBox is pretty much the finest front-end you could buy. Hook one of these puppies into your rack with a decent power amp and get ready for sonic amazement.

The Last Word(s)

After using this unit in my studio for three or so weeks I had completed a number of mixes where virtually every track was recorded through the VoxBox. Listening to these mixes compared to other mixes I’ve tracked in this studio was the final eye-opener. The difference in the detail and clarity of parts was quite noticeable. Vocals were more up-front and had that magical studio sheen to them. Hi-hats sizzled clearly – none of that grungy staticky sound. Bass guitar had lots of low end definition without getting boomy or heavy. Distorted electric guitars were thick and saturated sounding.

Remember I said I’d rather spend a $5000 budget on a $4000 preamp and a $1000 mic? Well, here’s why. When you buy a great mic and a “decent” mic pre, then all your other mics are limited to the “decent” sound of the preamp. Your M149 will sound great, but what’re you going to do about your AT4050s?

On the other hand, with a $4000 preamp, you can get more out of every track you record with any mic. It was highly evident in my mixes. I became completely satisfied with the sound of my 4050’s on vocals -and amazed at the sound of all my other mics too.

The Manley VoxBox might be the finest mic preamp / multiprocessor combo ever built. If you can justify the cost, do not shudder. Run, don’t walk, to a Manley dealer or the Manley website and get one of these suckers pronto.