Reverb Foundry HD Cart - User review - Gearspace.com
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Reverb Foundry HD Cart
4.75 4.75 out of 5, based on 2 Reviews

A new company with a strong pedigree is bringing back one elusive reverb from the past.

18th January 2018

Reverb Foundry HD Cart by Diogo C

Reverb Foundry HD Cart

Product: HD Cart
Developer: Reverb Foundry
Formats: AAX, AU and VST for Mac (10.7+) or Windows (7+)
DRM: iLok with two concurrent activations
Demo: Fully functional for 14 days
Price: $199 (USD/MSRP)

The scope: Reverb Foundry is the latest enterprise from reverb plug-in wizard Matthew Hill, known for his work under the LiquidSonics moniker, which recently made quite an impact with the Fusion-IR technology debuted on Reverberate 2 and also with their reproduction of the Bricasti M7 reverb on the Seventh Heaven Professional plug-in. This time a different route is taken and HD Cart differentiates itself from the LiquidSonics reverbs by relying on pure code instead of impulse responses - right now both names converge on the idea of bringing coveted hardware reverbs to plug-in form but HD Cart has nothing to do with convolution and it’s an algorithmic reverb at heart. Most importantly, instead of the Briscati now we have a rare and very special version of the revered Lexicon 480L - one equipped with the elusive “HD” cartridge, also known as “surround” or “HD Cart”.

According to the user manual, here’s what the HD Cart is all about: "One of the expansion cartridges for this unit contained the only algorithm to ever fully take advantage of its considerable dual-board processing capabilities. This amazing program was capable of being used in quadraphonic, 5.0 surround or high-density stereo reverb modes. The surround mode takes a stereo input and produces four-channel quadraphonic output (5.0 is also supported in this plug-in via a recommended routing patch). The HD mode mixes the quad outputs down to a two-channel stereo reverb, resulting in denser, richer audio unlike any other reverb processor."

The HD Cart plug-in follows to some extent the original controls present on the 480L hardware, so the terminology should be mostly familiar to users of other Lexicon reverbs. Controls are agrupated under five pages with five controls for each respective page. A "master" front page brings the most used controls such as tail/reflection levels and their respective roll-off frequency, while the four other pages (character, low control, advanced, reflections) provides deeper tweaks to specific portions of the reverb. A novel feature introduced by the HD Cart is the Recirculation parameter, which according to Reverb Foundry is a "an enhancement of the original algorithm provides a new reverb topology never heard before, even for users of the original expansion cartridge. Originally comprising two distinct reverbs combined at a late stage, it can be modified by interconnecting them at key points within the algorithm resulting in a more spacious higher quality reverb". In practical terms it means a very dense sound that really stands out, so if you like subtle reverbs you might want to this off, which is also advisable if you’re aiming for authenticity when compared to the original hardware. Besides this feature everything else is aimed towards offering the user an experience that is as authentic as possible, and the 40 presets present on this plug-in offers a great chunk of the coveted "Lexicon sound" that is heard on so many great albums. Load a preset, tweak them accordingly and great results will inevitably come.

Sound quality: I won’t dare to compare it to the hardware since I have no experience with the original unit, which I believe will be the case with most people out there since it’s 480s aren’t exact abundant these days, let alone a full working one with the HD Cart, so I’ll approach this from the perspective of someone who owns hundreds of plug-ins and who has tried basically every VST/AU/AAX reverberator under the sun. With that out of the way, this plug-in is definitely among the best reverbs I’ve ever tried, it sounds really good and delivers what I like to call the "Lexicon character", which to my ears is a certain grainy sound that I hear across the Lexicon PCM/LXP plug-in lines and also on the Relab or UAD emulations. HD Cart belongs in that group with a rich sound that will be very useful for certain applications - I take it more as a specialized tool than as a workhorse for most occasions, but that’s what I think about reverbs in general as I’m yet to find one that "conquers them all" and at this point I’m starting to doubt if such unit even exists. Which leads us to gear hoarding, which has become quite a problematic aspect of modern DAW-based production since it’s easy to drown in this vast ocean of options, and reverb is one area where I’m particularly prone to hoarding and guilty of owning many. Like a wise Gearslut once said, "I need a new reverb like I need a hole in my head", but it’s hard to resist when offerings as good as the HD Cart are on the table and at this point my heads looks more and more like a Swiss cheese.

Ease of use: HD Cart is easy to use for the most part, the interface is clean, the layout of controls is well organized and easy to read for the most part. Fonts could be a bit bigger but it’s not small to the point where it comes hard to read, it’s okay at a resolution of 1080p and only problematic if you go above that. The controls are mostly easy to understand, and as said before if you’re acquainted with Lexicon reverbs it will be an easy ride since most parameters resembles their units and will likely be familiar to users of the 480L, PCM and LXP reverbs. If that’s not the case then it should take some time and the learning curve will probably be a bit steeper than other reverbs since the terminology is a bit specific and it will take some time to get a hold of what each controls does. If further clarification is required the user guide is there to provide it, with 11 pages containing clear explanations of all the parameters, which definitely helps a lot. On the other hand, when it comes to reverbs the most common approach is to use presets at least as starting points for a sound, and while this plug-in brings a good number of them (40 to be exact) I think there could be more presets and most importantly, they could be a bit more application-oriented, with parent/child categories for each type of reverb or usage situation and so forth. Nevertheless, the included presets are a good showcase the HD Cart’s capabilities and should be enough to point users towards the desired results. However, the most problematic aspect in the ease of use department is the lack of assignable controllers, which is a hallmark feature of the 480L with its iconic remote controller and it’s surprisingly missing on this plug-in. Since the interface is rather slim on the vertical axis there could easily be an extra row below the current controllers to house four or five assignable encoders or knobs. This would add a lot to the ease of use since it would provide quick access to a certain setting while also avoiding the extra clicks spent on page browsing, enabling a much faster workflow. To be honest, I think that in 2017 we should have macro-controls to enable all sorts of morphings and modulations but I’d be happy with a few simple assignable controllers. Lastly, it’s also important to note that this is a very nicely coded plug-in with a modest CPU load, which is always a great thing.

Reverb Foundry HD Cart-screen-shot-2018-01-18-5.02.20-pm.png
A very slick and good looking interface, although I miss some assignable controllers for a faster workflow

Features: Little to complain here, and other than the aforementioned assignable controllers and a more comprehensive preset selection there’s nothing else I miss on HD Cart. I wouldn’t mind a resizable interface, input/output level trims and other bells & whistles, but as it stands it’s a solid feature set that fulfills its purpose. I appreciate the fact that Input/Output meters were included, it’s something overlooked on some reverb plug-ins but that I think should be mandatory. There’s also a good preset browser that allows users to store their own presets and options to initialize the plug-in with certain settings, which is a very nice touch. Lastly, I’d like to see a button to open the user guide from the plug-in, something I wish became a standard and present on every plug-in.

Bang for buck: Determining the value of a plug-in is a wildly subjective and often fruitless exercise since there are a few key variables that will drastically change according to each person, their taste, expectations and requirements. With that in mind, I think the asking price is very reasonable for a tool of this quality and given Matthew’s flawless track record with LiquidSonics there’s no reason to believe that this plug-in will be abandoned without updates, and that’s something that counts a lot in my book as I like my plug-ins to be as future-proof as they can be. Ultimately it comes down to whether or not HD Cart delivers the sounds you want or need, but at least to the ears of this reviewer it’s one of the best sounding Lexicon-based reverbs plug-ins right now, which is quite an achievement since there’s some pretty stiff competition out there. A very solid effort by Reverb Foundry, and I’m truly looking forward to their future developments.

  • Rich sounding
  • Mostly easy to use
  • Clean interface
  • CPU-friendly

  • Hardly any, but a low-budget version a la LiquidSonics Seventh Heaven would be nice to see

  • Assignable controllers
  • More presets
  • Resizable interface

Attached Thumbnails
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  • 5
17th October 2021

Reverb Foundry HD Cart by Sound-Guy

  • Sound Quality 5 out of 5
  • Ease of use 5 out of 5
  • Features 5 out of 5
  • Bang for buck 5 out of 5
  • Overall: 5
Reverb Foundry HD Cart

HD-Cart from the Reverb Foundry

Just when you thought you knew all the players in the reverb plug-in game, along comes the Reverb Foundry. And you find out they’ve been around a few years! And just when you figured that convolution reverbs are the pinnacle and future of reverberation modelling, along comes a purely algorithmic design that brings back to life one of the most famous “hardware” digital reverbs, the Lexicon 480L with its optional “HD” cartridge.


Oddly, I hadn’t run across Reverb Foundry or the original HD-Cart review (Reverb Foundry HD Cart) until I was looking for some of my own older reviews on Gearspace. It struck me as a fascinating plug-in for surround sound work, and by happenstance I am in process of setting up more speakers in my studio for just that.

What is it?
First off, what is a Lexicon 480L and what is the “HD” cartridge? In Lexicon’s own words, the 480L is “the standard by which all other signal processors are measured . . . The most realistic reverb available with stunning effects that maintain the harmonic integrity of the incoming signal through to the output.” It was released in 1986 (at a rather steep price of US$20,000!) and had dual processors (called Machines) that each could handle stereo signals, so there were four electronically balanced outputs, but oddly there were only two inputs! The two inputs could be sent to “Machine A” and “Machine B” in various ways, such as cascaded through “A” to “B” with auxiliary outputs taken from “A” and main outputs from “B”, or a stereo split configuration with left and right inputs sent to both “A” and “B” in parallel so that two different processing algorithms could be used on the input signal at the same time. This is the mode used by the HD cartridge, also called the “Surround” cartridge. It took advantage of the 480L’s dual-board processing capabilities to create a front reverberation effect in one machine and a rear reverberation effect in the other, and provide these separately on the four output jacks.

As the original review reveals, Reverb Foundry has been around a few years and is actually the brain-child of Matt Hill, who also created the LiquidSonics “brand” (and his famous Fusion-IR technology – see my Gearspace reviews of Reverberate 3 and Seventh Heaven). HD-Cart is a purely algorithmic design and the first reverb product in the foundry, but Matt hints that there will be more. CD-Cart emulates the Lexicon 480L (with the HD Surround cartridge), which itself was an early algorithmic reverb unit.

What the previous HD-Cart review does not elaborate on was how to actually use the four channel surround capability and use the HD mode (High Density in case you were wondering) which is something unique and effective.

All Around Sound
HD-Cart has the usual left and right input channels and when used on a stereo track you automatically obtain the HD mode. Like the original, HD-Cart creates the front and rear reverberation effects internally, but if you have only stereo outputs how can you use these four audio streams? The answer is HD mode which mixes the front and rear signals of HD-Cart down to a two-channel stereo output, resulting in a dense and very rich sound. The balance of the front and rear effects can be freely adjusted using the cleverly named Front/Rear control so that a wide range of tonal quality is available in the HD stereo mode.

But, if you have a DAW capable of hosting more than two audio streams on a track (such as REAPER) you’ll have access to four outputs and can separate front and the rear pairs to actually listen to full surround reverberation (assuming your audio interface has four or more outputs and you have rear speakers!). And if your DAW does not support more than two audio channels per track you can use two instances of HD-Cart on two stereo tracks (each hosting the same audio file), and set one to process the front output and one to process the rear. This method also enables applying different decay times and other parameter variatons to the front and rear reverb generation algorithms. Since HD-Cart uses only a tiny fraction of CPU resources, multiple instances are no problem.

Advanced Controls
The front panel of HD-Cart is clearly arranged with a preset selection panel at the top, a big Reverb Time knob on the left and a big Wet/Dry Mix knob on the right. There are four level meters that show input and total output levels on the left, and the output levels for early reflections and for reverberation on the right side. And there is a section in the lower centre for accessing additional parameters.

The reverb time knob reduces or increases the reverberation time – each preset includes a default reverb time, but since this is an algorithmic unit, the time can be changed to fit your needs (from as low as 20 msec to 62 seconds – with the minimum and maximum values affected by the Size control described later). Remember, an algorithmic reverb has no samples or impulse responses that impress a characteristic to the reverberation – all the presets are simply a set of parameter settings. And there are quite a few parameters; in fact HD-Cart has all the controls available on the original unit. In addition to the two big knobs, there are five controls in each of five panels (Master, Character, Low Control, Advanced and Reflections) – actually six controls in the Reflections panel. So, in total there are 28 parameters that can be adjusted and saved to a user preset. You can also use DAW automation to change any parameter “on-the-fly” as will be discussed later.

You can see the Master panel in the screen shot at the beginning of this article, and view the other four panels below. There are controls for both the reverberant field (the reverberation tail) and the reflections (early reflections that provide a sense of the space). The Master panel has an overall Gain control and separate level and low pass filtering for both the reverberant field (Reverb – Rolloff) and the early reflections (Reflections – Rolloff). The Character panel includes Pre-delay (delay time between the early/dry signals and start the late reverberant field), Diffusion (low diffusion simulates a very reflective environment while high values simulate a more absorptive space), Spread (which creates a complex function of delays that affects perception of the room size), Size (affects reverb time, room tone and the perceived dimensions of the simulated room), and Spin Rate (rate of a modulation effect that helps reduce resonances and audible repetitions within the reverb algorithm).


The Low Control panel includes a Bass Decay rate multiplier for signals below the Frequency setting and a Low Boost control with a low-pass Frequency setting and Pre-delay for the selected bass range – this can add a sense of space, especially for long delay times. The Advanced panel has a Treble Decay adjustment to set the relative decay time for high frequencies of the reverberant field, with the corner frequency set by a Frequency control. There is a Recirculation control to select the original Lexicon method or an advanced mode for routing the internal signals in the reverberation algorithm. There is also the very useful Front/Rear balance control and a Wander setting that sets the level of the modulation described above for the Spin Rate control in the Character panel.


Note the Front/Rear control operates differently for the HD stereo mode and four channel surround mode: in HD stereo mode it adjusts the contribution of front and rear reverb levels to the resulting stereo output while in surround mode it determines the relative level of the front and rear output channels.

Finally there is a Reflections panel with a Front Delay time control, a Rear level control, a rear Delay control, and a low pass filter frequency Cutoff setting along with a Spin Rate control that adjusts the modulation rate of the reflections. These controls affect only early reflections. There is also a small switch below the rear Delay knob that adds some magic that the original hardware lacked – it switches the rear reflections from mono (as in the original 480L) to stereo. Mono makes sense if a large space is being modelled since sounds coming from far behind you won’t have clear left/right distinction, while the stereo mode really brings a small room to life.

If all this seems a bit complicated, you should read the original Lexicon 480L Owners Manual – all 144 pages of it! The basic operation and MIDI control sections alone are over 30 pages (to be honest this manual also describes over a dozen different “banks” of algorithms, but not the HD cartridge since it was an optional unit).

MIDI Anyone?
The original Gearspace HD-Cart review noted, “the most problematic aspect in the ease of use department is the lack of assignable controllers (MIDI Learn)”, part of which is still true (there is no MIDI Learn). But I don’t find this to be an issue since HD-Cart does provide automation control for every HD-Cart parameter, which in this case is 28 parameters. Using Studio One and my FaderPort 16 with the updates PreSonus introduced about a year ago, I can directly control the first 16 parameters and instantly shift once to access the remaining 12 parameters as needed. And I can record any/all fader movements in real-time. Another benefit I find using this is that I can control HD-Cart parameters even when they are not showing in the GUI (since you can see only one of the lower control panels at a time). So no switching of GUI views is required.

In addition, the FaderPort automatically provides the name of each HD-Cart control and its current setting (such as +6.4 dB or 8.6 kHz) in its electronic scribble-strip. To be honest, a few controls display a scaled setting that doesn’t match the software value, but I use my ears when adjusting parameters, so the actual setting value isn’t critical for me. The FaderPort also cleverly abbreviates control names, but I’ve found it’s usually easy to figure most control ID’s instantly. I’ve used MIDI Learn at times with other programs and its strength is being able to choose which parameters to control and which hardware control affects which parameter. Its weakness is needing to make these control links one at a time if you want access to many parameters. Using automation control as I do with the FaderPort takes only a split-second to set up all 28 controls. And I find the ones most likely to be used, the main controls, are among the first listed.

As a point of historical reference, the original Lexicon LARC remote control unit had only six fader controls and required switching banks for more than six parameters, and even required switching between Machine A and Machine B to set each group of parameters (“The LARC can display and provide slider control for six parameters at a time. Because most algorithms have more than six parameters, they are grouped in blocks of six called pages.” – Lexicon 480L Owner’s Manual). For my money, the controllability of HD-Cart is a vast improvement over the original.

How Does It Sound?
HD-Cart provides a fine realistic sounding range of modelled spaces, with very dense reverberation effects possible in the HD stereo mode and excellent 3D surround sound reverberation effects if you have four speakers and an appropriate audio interface. Although not a “colourful” special effects processor, you can model some “impossible” (or at least improbable) rooms by odd parameter combinations (long front reflection delay with short rear reflection delay, very long high frequency decay time with short bass decay, etc.). But HD-Cart excels at creating 3D spaces with a real sense of being in the room, be it a very small space or a huge hall.

Tech Data
HD-Cart is available in 64 bit VST2.4, VST3, AU and AAX formats for Windows (Windows 7 or above) and Mac OS X 10.9 or above. Note that 32-bit DAWs are still supported (why would you want one?), but the 32-bit version will not receive any future updates. HD-Cart uses the iLok/Pace activation system and operates with iLok 2 or 3 USB dongles, iLok Machine activation or iLok Cloud. Since the iLok system is often updated, be sure to check iLok.com and download the newest version before trying to use HD-Cart (it requires iLok License Manager v5.4 and up). And be sure to be online when you first open it in a DAW because you will get an activation screen that needs to connect to iLok. Enter your activation code and then go to your iLok account to select the activation mode you want. Both Cloud and Machine activation are free, but Cloud requires being actively online whenever you first start using an instance of HD-Cart in a project.

In my test system (PC Audio Labs Rok Box PC with Windows 7, 64 Bit, 4-Core Intel i7-4770K, 3.5 GHz, and 16 GB RAM) HD-Cart uses about 0.3% CPU resources with little change when using different settings. No problem using several if a project requires it. Latency is zero.

HD-Cart is a fine emulation of a very famous expansion cartridge operating in a Lexicon 480L that creates “quad” reverberation, both in a true surround mode or in a complex and dense stereo mode. It is available as I write this, on sale for US$79, which is far less than a used HD cartridge alone (and a used 480L can set you back $4,000 or more and might need a bit of professional maintenance). I don’t have a real 480L to run comparisons, but considering it had less processing power than your mobile phone, I would expect HD-Cart is very close to the Lexicon vibe. You can get the demo to use for 14 days by entering the iLok code shown on the site (click the HD Cart Demo Instructions icon), although I’d bet it won’t take that long to realize you really love what it can do!

A Lexicon 480L with the legendary HD “Surround” cartridge!

Provides the full complement of controls available in the original unit.

An algorithmic reverberator with very flexible and broad range of control.

Can use DAW automation to change settings for even more variation of effects.

Can create, and record, four audio channels of beautifully modeled reflections and reverberation for a stereo or mono input track (easy-peasy in REAPER, a bit more complicated in some DAWs).

Handy metering of the input, output, early reflections and late reverberation component levels.

Free 14 day trial available.

At less than 1% the cost of the original hardware’s release price, HD-Cart is a bargain – and at the current sale price is virtually a “steal”.

I find nothing really to complain about. A truly amazing emulation of a classic reverberation device.


Attached Thumbnails
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