Review: miniDSP DDRC-88BM 8-Channel Dirac Live Processor With Bass Management - Home Theater Forum and Systems -

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Wayne Myers
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Review: miniDSP DDRC-88BM 8-Channel Dirac Live Processor With Bass Management


by Wayne Myers

Price Each: $999


MiniDSP has become a solid source for hardware-based Dirac Live implementations in recent years. Their products cover a range from two-channel 24b-96kbps models to eight-channel 24b-48kbps nano-sized and rack-mount models. But their offerings have fallen short in situations where AVR-embedded room correction has been entrenched for many years.

One reason for this in the eyes of some potential users is the need or desire to follow an AVR’s built-in audio processing with the DL correction. MiniDSP models operating in the HDMI stream allow only LPCM audio data, limiting source options. More recently the DDRC-88A, an 8-channel model with analog ins and outs, allows Dirac Live to process an AVR’s preamp outputs, so each speaker channel can be processed separately, a must with an ATMOS system, opening up the AVR’s control and source options again. But the ever-so-important home theater audio area of bass management remained within the AVR, so bass management, along with room correction Parametric pre-EQ, remained just out of reach for many home theater enthusiasts.

I have reviewed a number of those products from miniDSP and found them to be very capable, and the Dirac Live implementations to be excellent. But users who desired properly-situated bass management - before DL, so DL correction continues to work on a channel-per-speaker basis - still waited for their solution, which would also include per-channel delays and parametric EQ for subwoofer fine-tuning duties.

The new DDRC-88A_BM (88BM) brings firmware and plugin feature changes to the 88A which allow a complete 8-channel analog-in and -out room correction package with bass management before and parametric EQ and delay controls after, all the features the home theater buff could hope for exactly where they belong in the system. It is not an inexpensive product, but those who are fanatical about great bass and need some high-quality room correction are generally willing to spend a bit to properly satisfy these needs.

Who Needs Room Correction?

Needs are relative. Some will argue that room correction is not a need at all, that with treatment and decent speakers - $1000 to $5000 per pair - nearly anyone’s tastes can be satisfied. And here is the rub: Satisfied is relative, too. I will argue, and so far I have come across no exceptions to this position, that anyone (1) not pre-biased against room correction, who has heard a Dirac Live implementation that (2) does not limit system volume-producing capability, and (3) is situated to not interfere with AVR source and processing options, will embrace it enthusiastically. A decent system invariably will sound better, probably much better. A good system will sound excellent. And an excellent system will sound stunning. Dirac Live is simply that good. Then the level of performance that once satisfied becomes humdrum, and the need the bar is raised to the level where DL’s correction is as optional as the oxygen in the room. With the bonus of versatile bass management that can work with ATMOS and any imaginable configuration of subwoofers, the 88BM almost becomes a no-brainer purchase. Try it once, properly set up, and there is no going back.

There are those who will argue that room correction is an aberration with more downside than upside, and “experts” abound who quote studies to support the position. To put the position in perspective, and the argument to rest (as far as I am concerned), I have heard rooms where room correction did NOT help, and they were so bad acoustically that even a newbie would shudder and give up in despair. The rooms in use for serious cinema or music listening setups almost universally benefit by leaps and bounds from room correction, especially Dirac Live.


I am a little embarrassed at how long it took to complete this review. The false starts and hickups mainly were a result of being in a hurry and not thinking through to the end the process called for, and simply not paying proper attention to detail where the details were next to overwhelming. This is a lesson I seem doomed to re-live about once a year. Most systems will not involve the complexity that I had taken on, but the importance of taking care in that process is worth reiterating.

I approached this review with the goal of answering several specific questions. One complaint to be addressed is that a DL setup reduces and limits maximum volume in a system. More than one music lover who likes to be able to listen LOUD once in awhile and does not have 10 dB of system gain to spare has passed on DL for this reason.
  • Can DL be implemented effectively with no significant loss in system volume? Along with that, what is a good system gain and dynamic range management strategy for a DL implementation? Noise floor and headroom clipping issues must be addressed.
  • Do the extra stages of AD and DA conversion cause any audible signal degradation?
  • Are bass management capability and effectiveness in general improved by the design? Is PEQ useful as implemented? Are multiple subs accommodated?
  • What is a good process for setup of a more complex system involving multiple LR Mains speaker pairs and active crossovers and subwoofers acting in stereo, mono, and both-at-once (huh?) modes, including, perhaps, a checklist?
  • Does the 88A sound better in bass management terms than the nanoAVR-DL, acting all in the digital realm before the AVR and its built-in bass management?
  • How well - or poorly - can speakers be set up and be improved in an impressive way by DL?

Lessons Learned

Along with having those questions answered, some other accomplishments should be noted:
  • I realized that a statement I have often made, “Room correction with Dirac Live is easy,” is not really quote true. The part of the process I focused on when making that statement, the mic setup pattern used during DL calibration, is infinitely more forgiving than with the competing AVR-based products. But there are many other factors to keep straight in successfully putting together a DL-corrected system. Both miniDSP and Dirac Research have online guides and user support available. But a one-stop, start-to-finish detailed guide would be nice, and none of the guides I looked at contained the details I would have needed.
  • Good bass can be very addictive. I have long appreciated good bass, but never chased after it very hard. The 88BM provides an extensive set of tools for its attainment, and once attained it is very hard to do without.
  • This is not a recommendation, only an observation. At one point, in a bit of a rush to see the channel gain results for different calibration signal levels, I did several quick calibrations with only three mic calibration points, the LP, a foot straight forward, and another foot farther forward. The soundstage and imaging (SS&I) result was very good. Consider it a testament to how effectively the technology works.
  • Dirac Live (DL) correction is not quite as impressive when the uncorrected setup is excellent already. My own fault for spending a week on speaker setup and room treatment before starting to work with DL calibration. Most will be using DL because their speakers need the help, and the contrast will be more rewarding. For the record, the SS&I for my setup is still improved by DL, just not as dramatically as I have heard elsewhere.
  • Accurately measuring loudness with a complex music source is not a simple matter. We assume a SPL meter will do it accurately, especially with the aid of precision software like REW and a calibrated mic. This is true with a sine wave or with periodic pink noise and its limited crest factor, and the resulting RMS value will correspond to perceived loudness very well. But the way the psychoacoustic brain perceives loudness with a complex source like a music track is quite another matter. I used two different VST plugins with Reaper (one giving RMS and Peak readings relative to full scale, the other giving a Loudness Unit (LU) reading corresponding to the EU R128 standard) to analyze tracks for a listening loudness reading during each track’s loudest passages, to guide my volume settings while listening. Drastically different numbers were measured on tracks with greater dynamic range. I ended up looking for a way to rely on the LU reading, believing ti to be more accurate for music and cinema, and trying to find a way to relate the RMS and LU readings. A nifty solution presented itself, which will be described later.


The DDRC-88A_BM starts with the existing DDRC-88A design. A firmware change and the addition of a special plugin, the BM plugin, turns it into the DDRC-88A_BM, or sometimes it will be called the DDRC-88BM. Existing 88A users can perform the firmware change themselves, along with a little hardware fiddling with a cover removed, and then can run it with the BM plugin. New purchasers starting from scratch will receive the unit ready to go in firmware terms, as I did with the demo unit from miniDSP.

The front of the single-rack-space unit contains a rotary knob, which performs as a volume control and, with the help of a push-push switch, a preset selector switch. Four LEDs show which of the four presets is active. An additional LED indicates DL on/off status. The DL on/off and system mute functions are available via a generic remote programming process which only takes a few seconds with the specified remote. That programming consists of the 88BM learning the remote’s codes, not the other way around as is often the case with fancier remotes.

The rear panel is much busier, with two sets of eight RCA connectors for unbalanced ins and outs, terminal blocks for balanced connections, power, and USB 2.0 control connections. The 88BM is supplied with brackets for rack mounting, a USB cable, an HDMI cable, and optionally a UMIK-1 measurement microphone, the only model allowed by the DL calibration utilities for miniDSP products.

Logically, the 88BM contains five sections of audio functions.
  1. With the Bass Management function, first, one can set which channels feed to bass management, crossover frequencies and slopes (HP and LP independently), and the BM feed level.
  2. The Routing Matrix allows one to decide which channels will be affected by each of the eight available DL channels, with gain for each matrix point.
  3. The DL section shows the gain and delay settings determined by the DL calibration program. They are not modifiable.
  4. The Mixing Matrix allows selection, with gain, for each DL channel to the output channels.
  5. Each of the eight output channels contains optional crossovers with frequencies and slopes (HP and LP independently), parametric EQ, gain, and delay. An output meter indicates RMS output level, along with a numeric readout. RMS metering is relative to the maximum sine wave level before clipping. All gains are settable in 0.1 dB increments. All delays are settable in 20 uS increments.

The DL calibration is completed with the DL Calibration Tool from miniDSP, and the other functions and settings are controlled with the 88BM Control Utility. Only one of these two programs can be running at once in your PC. Room EQ Wizard can run along with the 88BM Control Utility, I used them extensively together.

The 88BM contains memory for four different DL calibrations, each with its own settings for the rest of the 88BM functions. While setting up the non-DL functions of the 88BM, it is important to work with an unpopulated DL memory position, as there is a gain and delay introduced whenever a memory position is populated with a DL preset. They can be “emptied” using the master reset function in the BM Control Utility, which erases ALL settings for ALL channels, or with the DL Calibration Tool, which will clear the DL function for one memory slot at a time, leaving other settings in the 88BM intact.

Configuration and Setup

A checklist, a checklist, my kingdom for a checklist! Sounds a little like the battle cry of an OCD-detail-control-freak, right? In my case, I could not have survived without one, which is still evolving. My system consists of two pairs of L/R Mains, a pair of MartinLogan ESL hybrid electrostatics and a pair of LXmini two-way speakers. A JBL subwoofer is situated with the other speakers on each side, an ESL, an LXmini, and a JBL sub close together in L- and R-side mirrored clusters. That way the subs can be run in stereo mode, making use of a 120 Hz crossover to take over all of the low bass duties for either pair of mains. In effect, this creates two 3-way full-range systems. The LXmini, with its small LF driver, especially needs that support in order to play at higher volume levels. So this amounts to two configurations, one for each L/R mains pair, and the subs are all set to work with either set of mains.

It is not the purpose of this review to cover all of these configuration details, but a number of them must be mentioned in that they are directly pertinent to the goals of the review.

The subs also needed to serve the surround speakers below their 100 Hz cutoff frequency. With the subs tied and working together, the amount of surround-directed program material above 60 Hz (my chosen sub crossover freq) that might add confusing directional information to the soundstage, was assumed to be minimal. I never heard any evidence that conflicted with that decision. Dual inputs on the JBL subs allowed independent inputs from the miniDSP 2x8 unit performing active crossover duties for the two systems, and for the more typical tied-together subwoofer signal for surrounds, supplied from the 88A for those configurations and for a third configuration.

With that third configuration the subs are ganged together for all speakers in a more typical arrangement, with which I used a 60 Hz crossover to completely eliminate any signs of localization from the subs. This configuration works with the full-range hybrid electrostatics, not with the smaller LX-mini pair. Any one of these three configurations can be selected among using a single programmable remote for both of the mini DSP units.

The point of all that detail is that there was a lot to keep straight, and many was the time I was unable to do so, until I got very organized with a detailed rough-draft checklist and notes and with a number of different project configuration files for the different units for each of the presets and for the different tasks and stages of the setup and tuning process. Those details will be published separately from this review - some day soon - and a link will be added from here.

Dynamic Range Management

I began in the theoretical realm by determining maximum desired volume from my system. An instantaneous Peak SPL of 105 dB was readily achievable given speaker efficiency and amplification, and that peak value allowed for a range of average SPL values that would accommodate cinema, rock,and instrumental tracks as I like to listen to them, with average SPL approaching 95 dB on more compressed rock tracks. I rarely push it that loud, but like to be able to for a minute when inspired by a chorus of a favorite track. As it turns out, 85 and 90 dB levels were used the most, with 92 dB being the max I used.

A good deal of experimentation was involved in resolving the issue of dynamic range management with the 88BM. The LFE signal in a surround mix is always 10 dB lower than normal. In other words, the mix is created by the engineers, then the LFE signal is cut by 10 dB in the storage/transmission medium, to be boosted 10 dB before listening.

MiniDSP has two DL calibration programs, a 96 kbps version for two-channel models and a 48 kbps version for 8-channel home theater models, such as the nanoAVR-DL and the 88BM. In the multi-channel model, the option exists to select Stereo, 5.1, 7.1, or Custom modes. Be aware that this mode for a DL project can not be changed once measurements are taken, and if one attempts to do so, existing measurements for that project will be lost, so the proper mode must be chosen up front when starting a DL project.

I ended up using the Custom mode for my projects. My surround setup is 5.1 with Phantom Center Channel, so a 6-channel setup was selected. The screen for setting measurement levels then has a checkbox for the subwoofer channel, which is stuck “On” in all modes except Custom, and in those modes it is assumed that the LFE signal will receive its needed 10 dB boost in the DL Processing, NOT in the AVR. If it happens in the AVR, it will only happen again in the 88BM. So the individual DL processing channel gains after calibration will end up 10 dB lower and the LFE channel will remain at or about 0 dB (it was always exactly 0 dB for me), effectively giving that gain..And giving 10 dB of system loss to the unwary operator who does not realize what has happened. Also note that the main and surround DL channel gains jump by 10 dB when a level threshold is crossed.

When I started out with the 5.1 setting, the DL calibrations always ended up with that 10 dB loss in all of the channels but the LFE channel and the net 10 dB loss in overall volume. But the Custom configuration, with the subwoofer box unchecked always set the channel gains with no compensation for LFE level, assuming that will be done elsewhere. In my case, I let the Onkyo AVR take care of that boost. The result? All channel gains were equal in the 88BM, exactly what I wanted.

I was left scratching my head wondering what hoops users might end up jumping through to manage what amounts to a 20 dB difference between the LFE level and those of other channels, where the AVR gives 10 dB of boost (standard) and DL gives another 10 dB of boost. Turning down subwoofer level at the sub’s amplifier is probably what many would do. But in my case, I wanted levels that were usable without DL in action, without any of its delay or gain changes, so that would not work for my system. Using the Custom setting in DL setup was the change that was needed.

Also important are the speaker trim levels in the AVR. I ended up with them all at the exact same number so the AVR would not contribute to any gain funniness.

With the system gain maximized, the potential for noise floor problems increased, and I ended up having to re-route and re-group power cabling with the Furman Power Conditioner to eliminate some hum and system noise at higher volume settings. The reward of all of this work - experimentation over about a two-week period was involved - is black silence between the images in the soundstage, and maximum volume capability that borders on blistering.

Phantom Center Channel

The phantom center channel presents an additional challenge with DL. All segments of the signal chain should act as though the center channel exists, right up to the point where the power amp and speaker would be. DL will insist that a legitimate channel be in evidence for its calibration sweeps, and will generate correction filters for that channel, which will be unusable. The measurements will have been taken from a point close to equidistant between the L and R mains, but not perfectly placed. They will almost always yield a wildly vacillating HF range which will lead to a wildly vacillating DL correction curve and final frequency response, quite unpredictable, except for the fact it will predictably sound horrible. But the calibration will be completed that way anyway, just to make DL happy through the calibration process.

Then the mapping and mixing panels are changed so that during playback, the center channel signal is sent directly to the L and R channels and makes use of their DL corrections, ignoring the center channel DL correction from the calibration step. Each of these signals is attenuated by 5 dB in the mixing matrix. This would usually be 3 dB, but matching of L and R direct and reflected delay paths are such in this system that acoustical mixing is near ideal, and the 5 dB of pan law compensation is warranted, rather than 3 dB. The resulting center phantom image is so concise that listeners will be looking for a hidden center speaker somewhere, thinking a trick is being played at their expense.

After the phantom center channel re-map, the final important step was gain and delay trimming. With the 88A, the per-channel delay and gain settings are displayed on the third control panel of the application. I found it useful for the L and R Mains to UN-trim those values by adding compensation on the Output panel of the 88A. I knew the original distances and volumes to be correct, and the trims done by DL only messed with the imaging, slightly, but enough that I could tell it was not what it could be. Un-trimming them restored the tight centered image I wanted. While this is possible with the 88A, it is not with the nanoAVR-DL. The trim values are not shown and there is nowhere to correct those values anyway. While a fine point, it is an advantage of the processing power of the 88BM over the nanoAVR-DL design. A nanoAVR-DL in series with a nanoAVR-HD would allow for this correction, except for the fact that one does not know what correction to make without painstaking measurements

nanoAVR-DL Comparison

An exercise comparing bass management with the 88BM to bass management with a nanoAVR-DL, one after the AVR in the analog realm and the other before it in the ,HDMI realm, verified that, while the approach to target curves is slightly more complex with the nanoAVR-DL, the results sound a measure the same, assuming that the AVR’s bass management and the 88BM’s bass management settings are equivalent. The bass management controls in the 88BM outshine those in any AVR in terms of crossover frequency granularity, independent HF and LF control of frequency and slopes and levels, And the idealness of bass management after the AVR cannot be argued, and is a necessity with ATMOS and with other source and AVR processing requirements, but absent those variables and given the way most users will use the 88BM, the nanoAVR can give an identical result. Enough caveats, everyone?

Target Curves

DL’s customizable target curves are a major consideration. I have heard of users who complain about the DL Sound without tackling the target curves. The default that DL sets sounded anemic and drab to me, too, the first time I heard the result, but those target curves are so accessible and tweakable that to leave them alone and simply move on would be a travesty. My own favorite target curve has developed over time, including a small modification determined during the calibration and listening sessions for this review.

Users must plan on setting those curves to a personal favorite, and if that is not yet known, then plan on spending some time figuring out what it is. There is a tendency to look to the target curves recommended by experts resulting from extensive studies. I have not heard one that I cared for and some are scary in that people actually use them thinking they sound good because they were told they should.

Instead of starting with a recommended curve that seems close, then modifying it to taste. I suggest starting with FLAT and modifying to taste. DL allows easy on-screen target curve editing. After discovering that each curve is stored in a text file, I edited those files directly at the file level, where precise frequencies and 1/10th dB level accuracy are possible.

With the right tweeters, with clean and smooth highs, and with room treatment to eliminate disruptive reflections, it turns out that extended, flat HF response can be very pleasing.

Great Bass

The most important discoveries I made about great bass were between 80 Hz and 100 Hz. With kick drum and bass guitar, this range resonates with the solar plexus and adds a little punch to the mix. My target curve received a small lift at this frequency range, and I smiled on many a track afterward because of that little extra bit of energy in my chest. A return to 0 dB at 100 Hz is necessary because any lift at that frequency leads to a boxy sound on some instruments and sounds.

As mentioned, bass management at the right point in a system is important to bass hounds. The 88BM accomplishes this and does it with tremendous versatility. My system with stereo subs hybridized with 5.1 virtual dual subs comes from an evolution of needs, but illustrates the versatility afforded sub configuration and tuning with the 88BM. With 8 channels of DL, PEQ, and delay available, a 5.1 system can have 3 channels dedicated to subwoofer tuning.

Bass Hounds will tweak bass frequency response like I obsess over the factors contributing to SS&I. My approach to bass management is to run DL calibration and call it good - the result usually is excellent, at least to my satisfaction. And DL’s approach to filtering, using mixed-mode room correction filters, focusing on LF with minimum phase filters and higher bands using FIR linear-phase filtering techniques, seems to do an amazing job all by itself.

In most systems, proper positioning of the subwoofers is the correct place to start the LF optimization process. In mine, the stereo placement with output up to 120 Hz demands the subwoofers remain close to the L and R mains.

I did try adding a third subwoofer, positioned close to the front wall, tuned to the frequency of an annoying null in the left sub’s response around 150 Hz, with HP and LP filters in the 88BM limiting its output to a narrow band around that frequency, but the result was less than exciting. At that point, my patience for extensive bass-hound behaviors ran out, and I turned to other matters.

Bass Hounds take note, the tools available in the 88BM are extensive and so easy to use that the challenge of sub setup - and the pride you have always found in your efforts - are likely to become a thing of the past. Don’t fight it, just let go. It is perfectly healthy and well-adjusted behavior to set place your subs, make maybe one move for optimized combined response, run DL calibration, refine a little, and be done, and move on to enjoying the fruits of your labors.

Too Many Conversions?

I had only one real hesitation in this area, that DAC pre-ringing might result from the extra conversions in the 88BM. In corresponding with Dirac Research on the topic, wondering if the DL impulse response optimization magic that is designed into their technology might actually correct for this effect somewhat, they replied that it could do that for aberrations that are common to all of the channels being corrected by DL.

My measurements gave a surprising result. First I verified that my equipment could indeed measure pre-ringing were it present, using a competing stereo DAC with switchable DAC reconstruction filter types. I could, and the difference was audible. With the 88BM, however, I could measure no pre-ringing whatsoever, with or without DL correction applied. All I can say is that pre-ringing, when present and audible, tends to evidence as very slight HF spreading of imaging on sibilants and very high percussive sounds, along with a very slight splattering of those frequencies..When I say very slight, I mean that without a quick AB comparison, even an expert listener would probably never detect it. I was able to make such a comparison, and could hear none of with the 88BM, and in fact a stark absence of that effect was one of the characteristics of the 88BM’s sound that thrilled me on track after track.

Accurately Measuring Loudness

As stated earlier, a goal of this review was to determine if DL is implemented in the 88BM in a way that would not impact maximum system volume significantly. Accomplishing this lead to the topic of measuring system loudness level accurately, which I assumed at the outset was an easy matter. It was not. The usual method, using a RMS measurement averaged through a loud passage of a music track, compared to a RMS measurement of the corresponding pink noise reference level, was the starting point. Then the Loudness Unit (LU) measurement, which is a dB-based measurement derived from a EU standard, got my attention. and I started playing with it. Similar to an RMS measurement in its logarithmic nature, the LU takes peaks into account. With a conversion determined between the two, I could set the system volume level for an accurate LU for each track I listened to.


I had to include this heading to point out, with emphasis, that, as is usual with miniDSP’s products, I can think of nothing at all to complain about, and no reason to steer away from the 88BM for the functions it provides. The 88BM is extremely versatile and capable. Switching any function while music is playing is smooth with no pops or clicks The user interface is as straightforward as it can be for its level of capability. Sound quality is incredible. To quote Mary Poppins, “Practically perfect in every way.”

Listening Evaluation

Starting with target curves, I repeat my assertion that determining one’s favored target curve is a must. Why? Because we are individuals, regardless of what we have been told, and because we can, with DL, anyway. The details of my own will be documented separately, but amounts to 3 dB boost at 24 Hz (plenty, trust me), down to 2 dB at 100 Hz for that solar plexus punch, down to 0 at 120 Hz to avoid that dreaded boxiness, then flat except for a 1 dB lift between 2 and 3 kHz, and a slight drop off from 5 kHz to -3 dB at 16 kHz. That is a lot of HF information, and lesser tweeters might call for another approach. I love the high end and everything about that target curve, and repeat the assertion that DL without your favorite target curve is like a bun without the hotdog. Like a beach without sand. LIke... You get the idea.

Paul Simon, Late In The Evening - 90 LU
This is such a fun track. The volume was there, solid bass with PUNCH, smooth, clean highs, rhythm instruments scattered through the soundstage. When the horns kick in, you want to jump up and dance.
Tip Of My Tongue - Tubes - 90 LU
This crisp mix is particularly dynamic. A tight horn section, deep, solid bass, and strong male vocals let you hear the dynamic range of a system. The track starts with a bang, and I have become fond of using it as a first track when showing off a system and/or DL to guests.

Setting system level for 90 LU gave a very satisfying volume. The 95 LU level could easily be reached when a favorite track called for it, but 85 and 90 levels were used the most. Although I did get up to the 95 LU goal level a couple of times, it was louder than I liked and I pulled back quickly.

This late 80s mix by the Tubes is as good as I have heard from that time frame, when recording and mastering technology had become particularly strong, and before the volume wars set in. Combined synth and bass guitar are solid, and that solar plexus punch is very present on this track.There is no boominess on the lower vocal tones or drums, the horns and lead guitar are bright but well balanced, so I felt no need to pull back the volume when they took over. The bass sound is tight and centered in the mix, and even seemed depth perfect.
Everybody’s Gotta Learn Sometime - Beck - 90 LU
Beck’s voice shows no sign of boxiness and is precisely imaged So far the target curve is doing its job as planned. When hearing this track, guests wonder where the center channel speaker is hidden. The strings have a wonderful clean tonality. Cymbals are very clear and natural, and the bass guitar sounds real and is placed properly in mix. This is not easy or automatic to achieve. Bass through subs that are not well integrated can be strong and seem to stand by itself apart from mix, but this setup with 88BM and DL, could not be better integrated.

Beck’s Voice sibilants can sometimes smear left or right a little, usually left, and that is a sign that the listener’s head is not properly centered. With imaging this precise - it is very crisp all the way up through highest sibilant frequencies - it is obvious when any part of the image pulls to the side. It is an effect that one can only witness with precise system imaging, and then one is quickly spoiled and notices even slight imperfections.

Some will argue that the head in a vice effect is to be avoided, that softer imaging is preferred to such restriction. Of course, mushy imaging is always an option. So is lack of detail. So is lack of impact. So is lack of clarity and realism. Don’t turn to Dirac Live if sub-par performance is your goal.
Three Wishes - Roger Waters - 90 LU
At one time, this track was used as a deep bass stress track at our HTS speaker evaluations, the synthesized effects on the Genie’s voice go very deep and are very loud at a few points, making this track more dynamic than most at low frequencies. The Woman’s voice to the left was almost right beside the LP. DL sometimes pulls the soundstage in a little narrower, and did on this track, but the woman’s voice was much more distinctly placed. There was a slight tendency for the lowest LF part of that voice to be separate from the rest of it, This was the only time noticed that effect.

The final chorus got turned up to 95 LU just for fun. That is what having available volume and dynamic range is all about. You might not do that for every song, I sure don’t, but for a minute now and then, as inspired by the music, it is a necessity and a joy, and was no problem for this system.

Perfect World - Broken Bells - 90 LU
With the 88BM properly set up, I laughed out loud when I heard this track. The centered kick drum had PUNCH and was incredibly tight. Sometimes DL makes you forget about that low frequencies are omnidirectional,
Ain’t It A Shame - B-52’s - 90 LU
This is a standard imaging test track for me. An echo high and to the right was crisp and distinct. Cindy’s voice sheen was crystal clear and tight, a sure sign of tight SS&I above 8 kHz, a minor DL miracle.

I had to switch DL off for another listen, off and on several times and never a perceived volume level shift.
Vision Of A Kiss - B-52’s - 90 LU
The acoustic guitar is so tight, very alive, with great depth acuity. The Kick drum is very tight, again there is a tendency to, forget that low bass is omnidirectional. Superb subwoofer integration makes this happen.
Another Nail Through My Heart - Squeeze - 90 LU
I love what DL does to vocals, sharp, almost hard, but with no pain. Cymbals are gorgeous. Bass is even, perfection. I sounds like the mixing and mastering were all redone by Dirac Live, every part sounds perfected.
China Girl - David Bowie - 85 LU
An emotional moment, partly for David Bowie, partly for the song, lyrics, bass line, overall tightness and clarity. The 88BM removes all the distractions and excuses, lays all parts bare. Volume up to 90 LU. Bowie never sounded better.

There are those who will insist that BM and DL are false and will never be as good as the natural sound without them. I ask: What is good? What is natural? What about modern sound production and reproduction is so special that it is wrong to hear the music with this kind of clarity, detail, purity, balance, dynamic range, impact? What about it do you NOT like? I’ll bet with the 88BM and a little time and patience you can become a staunch convert and have moments like this every time you sit down to listen which will be a lot more often than before it sounded like THIS!
Summer’s Cauldron - XTC - 90 LU
This track has to be heard LOUD. The floor tom sound is big and precise and precisely located. The sound of the electric sitar stands out like a spot in time and space
was reserved for them from the beginning of time.
I Love You - Climax Blues Band - 90 LU
Vocal sibilants are so precise. I realise I use that word ad lot for the 88BM. The Kick drum is tight, has nice punch. Cymbals are gorgeously real.
Dont Panic - Coldplay - 90 LU
This track is a good test for bass level. Bass is very strong, but even, it fits, it is integrated, it resonates with the chest. There is detail I have not heard before.
One Voice - Wailin’ Jennys - 85 LU
Listening for boxiness, there is none. Vocals so clear and well-separated, even when they are close together. Many times “close together” is assumed to be “all in one spot.” With the 88BM and DL, the slight separation becomes clear, you can easily tell where each stands,the space between is empty, even if only an inch, like deep space from between galaxies has been delivered via this mix to that spot between her there and her there.
Trouble With Dreams - Eels - 85 LU
Started the track, then had to stop and think. How is the kick drum so cleanly localized, with such great depth acuity? “It’s a mystery.” I love the punch in the solar plexus, it never gets old. Sparkles in space.
I Keep Forgettin - David Bowie - 90 LU
Such a wonderful mix, horns, toms, xylophone, vocals, impact.
Late In The Evening - Paul Simon - 90 LU
Wow, just wow. Hard to believe there is no center channel..
Baby I’m A Fool - Melody Gardot - 85 LU
Have used this as a SS&I torture track, it has failed many speaker setups. Perfect tonal balance, Melody’s low voice can be difficult to image. It is perfect here.
Eleven Small Roaches - 85 LU
The Funky Avocado - 85 LU
Michael Hedges
The acoustic guitar sound is so natural, dynamic, rivaling the sound I have heard with horn loaded compression tweeters, although the soundstage character is farther back from the LP, and has the advantage of sub-millisecond time matching between acoustical signal paths.
Deadwing - Porcupine Tree - 5.1 DVD-A,mix from 5.1 FLAC - all tracks - 85 to 93 LU
Surround mode is where the 88BM shows off its stuff. I have had the opportunity to listen to 5.1 music mixes on some fine systems, but mine is the only one with DL and “proper” bass management. My newly-discovered appreciation for the bass profile in the DL target curves, the 80 to 90 Hz punch, greater dynamic range than before, all these factors together had me a bit excited for a full listen start to finish with this favorite album.

I saw PT play two nights in a row a few years back. One impression: That Stephen Wilson is punctual. Both concerts started within 30 seconds of the 8 PM starting time. And both 20-min breaks counted down from 20:00 to 0:00 on the projected display just as the boys strolled back onto the stage for their second set. The man pays attention to detail and attention to detail is a hallmark of all of Steven Wilson’s work. There is such a wealth of detail in these tracks, and only with DL have I been able to hear it all, the imaging is sharpened enough that little synthesizer parts and sounds and effects are revealed that were hidden on other systems.

Misc notes:

The tonal balance was perfect throughout. Bass was present, insistent, but never overbearing.

Through the intro to Deadwing, the synth dances around you and you are in the middle of the train station. Imaging and depth acuity were very precise.

The kick drum and bass punch on Shallow, even a bit from the snare, hit right there in the solar plexus. That solar plexus punch immerses the listener in a music mix in a totally different way than LFE effects. Your breathing, your diaphragm are involved, it is rhythmic, The effect says something like, Music Is Life, just TRY to stop listening.

Halo - I love the synth parts on this track, dancing around the mix, the synth a quiet screech There is a quality about the guitar that is hard to describe. Sharp but comfortable. Hard but gentle. Able to cut flesh but it caresses instead.

Arriving Somewhere - Nothing short of a spiritual experience for me, I have never heard it better. Guitars hang in the air, maracas dance from side to side, Steven’s voice defies the logic that says he can’t really be here in the room. The metal middle got extra volume, turned up to the peak for this album of 88 LU. Then 90. Electrifying. Vocal echoes go on and on, their space respected by the louder sounds on either side. I never noticed that before. Detail detail detail, there is no way to hear so much detail without clutter, not without DL.

Mellotron scratch - Imaging was seamless through a 270 degree arc, even lower notes and sounds. Vocal harmonies stand like a personal multi-Steven-Wilson performance. At times the imaging almost seemed too perfect, except that there is no such thing in high end audio. Some have the opportunity to hear tracks like this on a $50k to $100k system might be insulted by the notion that a pair of MartinLogan low-end electrostatics and a few thousand dollars of support gear could sound as good as High End. And they might be right. But it comes mighty close with the aid of DL and the 88BM.

Glass Arm Shattering
Big, huge, clean, dynamic. In the middle, the clean pure ting of a cymbal gives chills. Feeling all your love.. The final scratch sound goes around and around, not quite a perfect when moving across the back, between the two surrounds.
The Fifth Element - DVD
Collateral - Club Fever - DVD
Saving Private Ryan - Opening Battle Scene - Plex Server
Saving Private Ryan had been re-encoded for a family Plex Server, and the average level was clearly about 10 dB above reference level. I started out the battle scene at what should have been the 85 LU setting and got a brief taste of war that would have clipped or overheated of blown a fuse or breaker or driver something in the system. The scene is disturbing enough at a sane 85 LU volume level, Pulled down 10 dB, the scene was dynamic, had lots of punch, impactful bass and LFE, yet all was balanced and the dialogue was easy to understand throughout.

Fifth Element played well at 85 LU setting and Collateral got a boost to the 95 LU setting, a good listening level for each. Even with no center channel speaker, the dialogue was clear and easily understandable and completely natural in the soundstage, with tight imaging of voices and effects. Music was balanced with proper tonality. I felt that I had achieved target curves that would serve equally well for cinema soundtracks and for two-channel or surround music mixes.


Once in awhile you come across a piece of audio gear that acts as nothing short of a Value Multiplier for your system. The miniDSP DDRC-88A with Dirac Live plus BM firmware and plugin for Bass Management is a Value Multiplier if I ever heard one, Approach it with patience, Get to know its capabilities. Adopt it into your audio gear family with care, and it will reward you with refined soundstage, imaging, impact, clarity, and detail that might just kick your system’s asset level right into the extreme envy category. Count on the perceived value to be multiplied at least several times. Don’t fall in love, your 88BM is just a box of electronics. Do prepare to be spoiled, though, that much is unavoidable. And don’t feel guilty about the envy of your audio buddies, send them a link to the miniDSP site, there are plenty of 88BMs to go around.

Go to the Review Discussion Thread Here
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8channel , bass , ddrc88bm , dirac , live , management , minidsp , processor , review

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