Review – Imperial Delay from Boz Digital Labs


Could Boz Digital Labs Imperial Delay be the world’s greatest delay?  Curious?  Then read this review to find out.


by Dave Townsend, Jan. 2015


I have to thank Brandon Drury for making me look at this plugin. Brandon wrote a blog entry on his site entitled “Greatest Delay Plugin Ever”, which made the case that Boz Miller’s new Imperial Delay plugin was in fact The World’s Greatest Delay. Ever.

Now, I was aware that Brandon is a pal of Boz’s and therefore could have been biased in his assessment. But I also know Brandon’s a straight-talking guy and only occasionally prone to unwarranted hyperbolic rants, so there was nothing to do but have a look for myself.

Is this truly the Greatest Delay Ever? The short answer, for the impatient reader: yah, maybe.

At least, it’s certainly in the running for the crown. It deserves consideration for membership in the high-end club that includes long-time standards such as Sound Toys’ Echo Boy and the mind-bogglingly sophisticated FabFilter Timeless2. But whichever full-featured delay you decide is the “greatest” will mostly come down to personal preferences, hence my weasel-word “maybe”.

However, I can say this much with confidence: if you don’t decide Imperial Delay is in fact the greatest ever delay plugin, it won’t be because of any lacking features. It’s definitely got the feature set that you’d expect from a candidate for the title of “Greatest Delay Plugin Ever”.


Every Delay Feature You’ve Ever Heard Of

Delays have evolved over the years, getting ever more sophisticated with each generation. Once upon a time, host tempo-synchronization was an exotic feature. Now it’s standard. Ditto for tape emulation and ping-pong effects.  Nowadays, any top-tier delay is going to include such things, so let’s just say that Imperial Delay does all that too, and move on to the cool stuff.

There are a finite number of things you can design into a delay, most of which come down to how you process the feedback loop and how the delayed signal interacts with the dry signal.  I’ve run down that list and Imperial Delay pretty much checks off every bullet point.


Tape Emulation

We love tape delays because they don’t just go echo…echo…echo, they actually make audio sound more interesting. That’s because small variations in tape speed cause corresponding fluctuations in pitch. When you then combine the dry signal with a slightly pitch-shifted version and randomize the shift, the result is a chorus effect akin to double-tracking.

Digital plugins that purport to emulate tape delays therefore have to simulate the mechanical and electronic flaws that made tape delays sound so good:  inconsistent tape speed, loss of high frequencies and distortion. Imperial Delay does that stuff pretty well.

Tape speed variation, also known as “wow and flutter”, is simulated by modulating pitch in the feedback loop. Some delays let you tweak this behavior, but most rely on built-in algorithms that have been designed to mimic the variations in tape speed of classic tape machines. Imperial Delay gives you something a little extra: separate fully-adjustable pitch shift controls for left and right channels. More on that later.

Another aspect of tape is loss of high frequencies, which makes the delayed signal slightly muffled-sounding. A digital delay typically emulates this with a low-pass filter. FabFilter Timeless2 takes that to crazy extremes, with multiple filter types and the ability to modulate them several ways. Imperial Delay gives you just a simple “Color” control, which by default is just a standard low-pass filter. It would seem that Timeless wins this comparison. But wait – Imperial Delay has more than one non-obvious trick, as we’ll see.


Hiding Complexity

As features are piled onto any plugin, especially one that aspires to be the “greatest”, the plugin naturally becomes more and more complicated to figure out and use. The real challenge for any software developer isn’t making complicated stuff work, it’s making it accessible. Boz approached this challenge by hiding many of the more advanced options until they’re needed.

Case in point is the aforementioned “Color” parameter. When you look at Imperial Delay all you see is the one knob. If you want to keep things simple, you can stop there. But click on the little button to the right of the knob and you’ll be rewarded with a new panel and additional controls.

What we have here are three refinements to the “Color” adjustment. The top one turns the feedback filter into a tilt filter. The two sliders below it set the cutoff frequencies for the low- and high-pass filters, respectively. Below that is a button to select color presets, or to save your own.

Note the same little detail buttons next to most of the other controls. Each of them opens a similar panel for each of their associated controls, revealing advanced adjustments that are otherwise hidden until you need them.

I’m not going to walk you through every control on this plugin, just the more curious ones. I’ll leave the rest of it for you to explore and discover. Just remember that when you look at this plugin and see only a handful of knobs, don’t assume that this is some dumbed-down version with limited functionality. Be sure to explore all the hidden goodies.


Smearing Can Be a Good Thing

One of the more mysterious knobs is labeled “Smear”, not a standard control we usually see on delay plugins. In this plugin, “smear” refers to a kind of granular reverb effect that’s created via filtered regeneration, which makes the chain of echoes less distinct and more distant-sounding. In other words, “smeared”.

Turn the Smear knob to the right to increase the relative level of smeared signal. It’s a nice effect on sounds that you want to push into the background, such as pads and ethereal background vocals. Not an effect for in-your-face rock vocals, but in moderation it is quite nice on a mellow lead vocal.

Open the detail panel and you’ll see more adjustments for the smear effect. The first knob sets the amount of regenerative feedback, which changes the intensity of the smearing effect. Turn it counter-clockwise to dampen the regeneration and shorten the reverb-like sound. Turn it clockwise to exaggerate the effect.

“Size” is similar to the density control on a reverb. Counter-clockwise for dense, short delays in the feedback loop; clockwise for longer, sparser delays.

There’s also a low-pass filter and presets.



This is one of the coolest features, and although not unique to Imperial Delay it is disappointingly rare on delay plugins in general. I think it should be a standard feature – it’s that useful.

The concept is simple: suppress the delay while the input is hot, in order to improve clarity by limiting how much the echoes step on and mask the dry signal. The implementation is also simple: it’s just a compressor that keys off the dry signal but compresses the delayed signal.

This is one control that you’ll probably want to bring up the detail panel for, because it’s very helpful to see the relationship between signal and threshold and the advanced panel provides convenient peak and compression meters for this.

Set the threshold too high and the ducking effect won’t be heard. Set it too low and the delay can disappear altogether. You want to set the threshold such that the compressor is activated at the beginning of a phrase but releases at some point later in the phrase.

Ducking is most useful on material with strong attack transients such as vocals, piano and sometimes guitar. You probably won’t want to use it with pads, strings and background vocals.

As I said, the ducking feature is not unique to this plugin. However, in my opinion nobody else has managed to make ducking as convenient and easy to dial in as Boz has in this plugin.


Two-stage Feedback

Every delay offers a feedback adjustment to set how much of the delayed signal is fed back into the input, thus controlling how many echoes you hear. It’s often the most critical adjustment because if the feedback level is too high the dry signal can be overwhelmed by the effect. Too little, and you get an unnatural-sounding slapback that may not be what you wanted. The trick – and it’s a bit of an art – is adjusting the feedback just right so that you get a nice thick effect without stepping all over the vocal or instrument.

Imperial Delay gives you a tool that I believe is new (at least, I’ve never seen this feature before) and unique: a two-stage feedback option. It lets you set up two feedback levels, one for louder input signals and another for quieter input levels.

Take a lead guitar track for example. You could set up a low feedback amount that’s applied when the guitarist initially plucks a note, but specify a much higher feedback amount that takes over as the note fades away. As soon as the next note is struck, the low-feedback setting kicks back in, preserving the clarity of each note’s onset. Sustained notes can therefore be absolutely drenched in delay without turning the melody into mush.

This feature, especially when used in conjunction with the ducker, will let you go nuts with long, lush delays that would otherwise be just too much. Fast licks come through clearly, but whenever the player lingers on a sustained note, the delay can stretch that note out for as long as you like. Try it on a sultry saxophone solo – yikes.



There’s an old trick for thickening up vocals that involves cloning a vocal track twice and then shifting the pitch of one clone a few cents down and the other clone a few cents up. There are plugins, such as SoundToys’ Little Pitchshifter, that perform just this trick. There is a classic hardware device called the Eventide H3000 that famously does it. Imperial Delay puts a new spin on this classic effect by placing it into the delay’s feedback loop and letting you adjust the amount from subtle to intense.

Two little knobs labeled “PITCH L” and “PITCH R” adjust the amount of pitch shift for left and right channels from 0 to 100 cents (one semitone). Click the top button to enable the feature. Click the lock button to link the two pitch knobs together (I wish there was a way to lock them in opposite rotation, though). There are no advanced adjustments, so no hidden panel is needed for this feature.

The pitch shift is applied to the feedback loop, not to the main dry signal. This means that the shift becomes more pronounced with each echo, so the more feedback, and the greater the effect. Consequently, I prefer to use short feedback values with pitch-shift because I’m usually after a subtle effect. But you may be after something more extreme or exotic, such as a complex evolving pad, in which case high feedback plus pitch shift might be just the ticket.

More than any other of Imperial Delay’s features, this is the one that most sets the plugin apart from the rest.

OK, that, and the smear feature. And the ducker, of course. And the two-stage feedback. Yes, definitely, those three features plus the pitch shift make this plugin special. Um, and the distortion’s pretty good, too. And I haven’t even told you about the Width knob. So definitely, it’s those six features that distinguish this delay from the pack. Maybe one or two others.



So is this really the World’s Greatest Delay? It doesn’t have FabFilter Timeless2’s extensive modulation capabilities, so at least for some applications such as generating rhythms, Imperial Delay might not hold the top spot. It also doesn’t allow you to define, treat and pan each echo independently like, say, Audio Damage’s Ricochet or eaReckon’s EARebound, so there may be better choices for certain creative and sound-design applications.

But for the other 99% of everyday mixing needs, I can’t imagine wanting more in a delay plugin than what Imperial Delay provides. I really think I’d be OK if this was my one and only delay. (But no, I’m not letting go of Timeless2 just yet.)

OK, so we’ve established that Imperial Delay is capable and cool. What about value?

Ah, you knew there had to be a catch, didn’t you? Imperial Delay goes for $299. Ouch. That makes it the most-expensive delay plugin on the market. (By comparison, FabFilter’s Timeless2 is $144 and Soundtoys’ EchoBoy is $179. In fact, I can’t name any other full-featured delay plugin priced over $200.)

In its defense, I can only offer that a) it’s really good, b) it could be the only delay you’ll need, and c) occasional sales are likely. I’d suggest demoing it to see for yourself if it’s the Greatest Delay Plugin Ever – for you.

Purchase Imperial Delay or get the demo here:

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