System #45 (Monolith IIIx, SL3XC, Sequel II)

[JonFo]

Processor updates

… I’m looking to simplify my system …

Famous last words methinks.

Fewer boxes is indeed simpler, but the functions embedded in them are roughly still the same. Matter of fact, the DriveRack 4800 is a huge leap forward in features (and attendant complexity). Luckily, it has a great user interface (via PC’s) and combined with my years of DriveRack use with the 260’s, I was able to master it in short order. But simple? yeah, right

Before I jumped in and started ripping out gear and plugging in cables, I spent a day planning and writing up the steps I would take to perform the swap over. After 6 or so pages, I pretty much had it covered from tear-down to re-installation and initial gain calibration.
Yes, yes, call me anal-compulsive , but read on.

So I spent a few hours every morning for the past week on cable end labeling and equipment re-arrangement. This also let me do a better job of wire management (as Rich noted, I probably have more cables in active use than anyone I know). So now the back of the rack is a little neater. However it’s still a rats nest to some extent, fixing that would require a full tear-down of ALL gear and using custom length cabling for power and signal cables. A >$5K exercise, so I can live with a bit of mess, as it doesn’t affect the sound.

I finally got to the point of getting everything fired back up yesterday morning.

One observation about this is that as mentioned before, complexity is very high, and I think I just proved to myself that this must indeed be a hobby, as why else would I spend 15 or so hours planning and executing an equipment upgrade

 

[JonFo]

So now that the DriveRack 4800 is set up and running, how does it sound?

Really great is the short answer. It is indeed a step up from the Driverack 260, which is already a very good piece of gear. The added headroom from the improved gain structure (explained later) allows the improved A/D sampling to really shine. Likewise the improved algorithms for the building blocks inside the processor are very nice.
Also, having the four main channels (L/C/R + sub) handled in a single processor is a benefit for control and low-noise.

The overall dynamic range of the system seems to be about 10dB better than before.

Dumping the Behringer gear and extra cabling results in an inaudible noise floor. With the ear right up against the panels and the volume cranked up, I can hear absolutely nothing.

While I transferred the prior EQ settings form the 260’s, I’ve been doing some more measuring and re-tweaking for even better in-room balance and performance.

I do have say, the room treatments are astonishing in the effectiveness. The Bass (<80Hz) needed only three parametric bands of EQ. and mild cuts (less than 4dB) at that.

 

[JonFo]

DR4800 pic

Here is picture of the rack with the DriveRack 4800 in it.

The DR 260 on the lower shelf is for the rear speakers and the DR 4800 above handles the L/C/R + sub.

The mixer above it controls gain on the outputs of the Center line array and the left and right Monolith woofers. If my amps had built in gain controls, this piece would not be needed.
So I'm considering some more pro-amps (these are for woofers anyway) that have gain controls built in.

 

[JonFo]

DR4800 config

This is a screen cap of the primary configuration panel for the drive rack.

It depicts the input and processing flow of the system.

From left to right we see:

• Four inputs
  • Each feeding a graphic EQ (31 band) then feeding a Parametric EQ (9 band)
  • Then they feed a linked (all channels share same settings) module that performs sub-Harmonic synthesis ( DBX 120A processing).
  • The three front channels go into a linked Compressor module which is typically off. But would be very useful in a ‘party’ type preset.
  • The sub gets its own compressor settings, again typically off.
  • Then, finally an input delay setting for each channel. All off in my config.
• Top 7/8’s of the right side contain
  • Three Mixer/connectors in front of a linked insert for a feature called ‘AutoWarmth’ that I’ll explain further ahead
  • The left and right are plain connectors to their respective input chains
  • The mixer combines the Sub and the center
  • This is pretty cool, as if the LFE channel happens to have full range signals, the crossover will route them to the center (which is right on top of the sub). But even if it just contains signals up to 120hz, those will wind up in the center line-array of mid-bass drivers.
  • This all then feeds a 3-way x 7 output crossover that will be explained in greater detail below
  • Each crossover output is then fed to its own 6 band parametric EQ
  • The next insert is either a compressor or limiter to manage the energy going to the respective amp/driver combo. Limiters are used to guard against frying the mid-bass or subs. No limiting is applied to the panels as they can pretty much take all one can throw at them.
  • Although keeping the signal below the point where the amps clip is a very good idea, and once I calculate that, I might set up some limiters for the panels.
  • Next come individual output delays for both intra-speaker alignment and room layout alignment as I’ve described in other posts.
  • And finally, that’s it, the outputs feed the amps.
• The last line on the right is for the tactile transducer.
  • It’s input is a mixer, normally pulling just the LFE channel, but I wanted to have the option to capture ‘the feeling’ from the others if I wanted to.
  • The mixer feeds thhe same chain as noted above. I use its 1x1 crossover to limit the signal to 150hz and below.
  • Also, the compressor and limiter are really, really necessary here. One can indeed get too much of good thing from the Buttkicker, if ‘ya know what I mean

See, simple, less complex :haha1:

 

[VanDaRo]

I've always stuck with simplicity and purity in my system(s), keeping the signal path as untouched by circuitry as possible. Your system is the antithesis of this philosophy.

You either know something we don't or are a hopeless audio-geek !! :bowdown: I'd love to hear that rig... I'll bet it would make me rethink my values. :rocker:

~VDR

 

[JonFo]

...
You either know something we don't or are a hopeless audio-geek !! :bowdown: I'd love to hear that rig... I'll bet it would make me rethink my values. :rocker:

~VDR

Well, a little of both

The only pure system is a CD player and a set of headphones. And even then you are listening to what the producer though would be right for the playback context (which could assume anything from FM, to Car to in-room to cans).

If you listen to music through a system in a room, you are so beyond 'pure' it’s not even funny. That's why acoustics of the room both in terms of size/shape plus treatments are so critical. Then the manipulation of the sound in the room is the next, so EQ's are a must. Pure signals are pure anathema to accurate reproduction when the room is adding colorations that processing can mitigate. Although, one does need to do so judiciously.

Bottom line, every component in my complex chain is designed to address some in-room at listening position challenge and improve it.

Trust me. I’ve heard quite a few mega-buck systems, and this one is tops. I’m sure there are better out there, but not by too much.

If you’re in Atlanta, drop me a line about a get-together, guaranteed to change at least your outlook a bit

 

[JonFo]

Crossover details

Here is a shot of the Crossover details.

I use a Linkwitz-Riley high pass cornered at 314 Hz with a 36 dB/octave to feed the three front panels.
The bandpass for the woofers/line array is a low-pass at 314 Hz with a symmetrical 36 dB / octave LR. The high-pass at the other end is a LR 24 at 83 Hz
The woofer has a low-pass set at 83 Hz using a LR 24 slope.

The gain on the three panels is dropped by about 3 dB, which sort of disproves that ESL’s are inefficient. If you remove the passive crossovers, they are quite (a bit too) efficient.

The line-array and woofers, not so efficient, so gain is boosted 3 dB.

Sub amp has it’s own gain controls, so we leave the x-over gains alone (amp has roughly +4 Db)

Here’s the crossover pic:

 

[JonFo]

And this is the composite view of the output bands as affected by crossovers and EQ’s combined.

You can see that the EQ’s are fairly mild. But the results are pretty dramatic in terms of benefits.

It took dozens upon dozens of measurements to get to this result.

(the colors of each line correspond to the numbers on the right, which in turn correspond to the master layout image above)

 

[JonFo]

AutoWarmth

A very, very cool feature of the DR 4800 is the new ‘AutoWarmth’ module.

What this does is provide a dynamic adaptation of the system tonal response based on the human ear’s natural response changes as volume drops. This is the ‘Fletcher-Munson’ curve one hears about for adjusting frequency so perceived loudness is maintained irrespective of actual SPL. This also known as an “equal-loudness contour”.

The AutoWarmth module has a user controllable threshold setting (volume at which it takes effect) as well as variable ratios of application of the effect. Anywhere from 1/4 to 4x the effect can be applied.
Once the threshold is crossed, it dynamically EQ’s according to the curves and the current volume level.

It is very effective. I’ve been listening to some prog-rock this afternoon as I write all this up, and I’ve had it playing at an average of 73dB, but the fullness of the bass is all there.

It is miles ahead of the old ‘loudness’ controls, and nothing short of the new Audyssey Dynamic EQ found in the new Denon AVP-A1HD processor is even close to it.

Really, really dig this feature :rocker:

 

[JonFo]

Gain structure

One of the most important things to do in a complex system is to ensure that the gain structure of the rig is normalized. That is, that each piece of gear is operating in its optimal gain range, and that we are not introducing opportunities for distortion or limited headroom due to improper matching.

This becomes even more critical when interfacing consumer equipment to pro-gear, as I’m doing here.
The toughest item to deal with is the inputs. As pro-gear typically operates at +4 dBu and consumer gear at -10 dBu, there is a big gap in gain.

To interface consumer gear to pro gear, I recommend the use of the Jensen transformers I mentioned in prior posts in this thread to convert from unbalanced (typically RCA connectors) to Balanced (typically XLR connectors) with effective hum and ground suppression as well. However, these are typically only a 1:1 gain, so we still need the pro-gear to boost the input signal with its gain controls. Luckily, the DBX gear has very clean front ends and gain structure can be matched to consumer levels easily.

The new DR 4800 even has a very handy gain structure adjustment for the entire box with various output gain settings selectable.
In my system, an input gain sensitivity of 14 dBu before clip largely compensates for the 14 dB delta between pro and consumer levels. (note: the lower the input dBu, the more sensitive it is, that is more gain).
Likewise, the outputs are lowered to 12 dBu to better interface with my consumer Sunfire amps (even though they have balanced connectors). The lone pro-amp (a Crown for the IB sub) just gets its input gain tweaked to match.

Here’s how I set up my gain:

 

[JonFo]

Limiters - a good thing

Well, I just had my first occasion to be thankful for the limiters in the DriveRacks.

I was setting up the new Denon 2930ci universal player, and using its built-in test tones, adjusting the gains for analog 5.1 through the TA-P9000 preamp, and then exited the menu and hit play. And wham-O, huge blast of sound (guessing above 105 dB), as the tones are very low, but audio out levels higher by at least 10dB. The sub was ear-bleeding loud (of course, the disc was the Blue Man group - audio on DVD-Audio), but the IB sub did not bottom out (its amp will destroy voice coils as it's overpowered by a factor of 2x).

The limiters saved all the woofers. So I just had a payback on the DriveRack investment

Now, that ringing in my ears, it's worse ...

 

[Bernard]

Now, that ringing in my ears, it's worse ...

You have my sympathy; that can drive you round the bend. I hope it subsides.

 

[JonFo]

Well, at +1 weeks since the install of the 4800 and I’m still wowed by it.

This is an astonishingly clean piece, with no noise from it at any volume, even close up on the speaker.

Gain structure is now correctly set up thanks to the very flexible input selections from the DR4800.

To anyone doing Active crossovers on any speaker, this is the unit to get. It’s easy to use (well, relatively speaking ), has tons upon tons of controls, and is very transparent.

Another cool feature is the Real Time Analyzer, which shows the energy in the various frequency bands on the various inputs. You know, those dancing meters we all get mesmerized by
Anyway, the RTA on this unit let’s me look at any one input or the sums of any and all inputs.

Looking at the energy content of much of the music I listen to (lately, mostly Prog Rock), it is clear why good mid-bass performance is a must for satisfactory rock reproduction. The majority of the energy is in the 400Hz and below area. If your speakers, EQ and room tuning are not well balanced, it will just not sound right. A DriveRack gives me all the tools I need to get the most out the drivers and the room.

Also, I need to repeat my amazement at the AutoWarmth feature. This is an incredible innovation and provides very satisfactory low-volume playback. The dynamic EQ tracking of the equal-loudness contours are completely transparent and just provide a nice, even frequency response at any volume.

Oh, and it’s a tweakers dream. Sitting in my chair, running the GUI for it on my laptop (connected over WiFi into the network port on the 4800), one can just adjust anything an everything in real-time, or just watch the RTA light show. Too cool

 

[JonFo]

New pre-amp

Man, finally gave in and got the Denon AVP-A1HD Pre-amp (AKA: the holy grail )

New box is in the home, but other things are ahead of it. Just wait and see what posts the 4th of July. You'll like it

 

[STV]

Congratulations on the shiny new AVP! Got it a day early, that's too cool! Looking forward to seeing your posts July 4th.

Thanks for sharing the news.


Seth

 

[FatJ]

Congratulations on the shiny new AVP! Got it a day early, that's too cool! Looking forward to seeing your posts July 4th.

Thanks for sharing the news.


Seth

Got it a day early in more ways than one.... I just found out that Denon has raised the retail to $7500 effective yesterday! That might have changed negotiations

Enjoy it!

 

[STV]

Got it a day early in more ways than one.... I just found out that Denon has raised the retail to $7500 effective yesterday! That might have changed negotiations

Enjoy it!

That's right, the MSRP did go up to $7500. Your lucked out Jonathan.

 

[JonFo]

Got it a day early in more ways than one.... I just found out that Denon has raised the retail to $7500 effective yesterday! That might have changed negotiations

Enjoy it!

Wow, It sure pays to listen to ones instincts

That's right, the MSRP did go up to $7500. Your lucked out Jonathan.

Yep, big time. I hope it holds out on the sale of the old stuff now

I did do a 'pass it on' to the buyer of my old Behringer gear. He got a great deal as well.

 

[STV]

Wow, It sure pays to listen to ones instincts



Yep, big time. I hope it holds out on the sale of the old stuff now

I did do a 'pass it on' to the buyer of my old Behringer gear. He got a great deal as well.

Cool.

So how's it going with the setup so far? Once all is in place I can only imagine how it's all going to be. Looking forward to some pix.



Seth

 

[JonFo]

Hi Seth, I’m taking a breather today. Had family over and we stayed up late yesterday finishing work on the 'other' acoustics project (see preview here).

The AVP is just sitting pretty on the counter outside my HT. My brother in law just had to see what a 65 lb pre-amp felt like and tried to pick it up. Surprise, it's heavy

So I'm enjoying one of my last Trifield soundfield sessions on the Meridian front-end. Hard to imagine something better than this, but we’ll see. I’ll be doing a shootout between the two.
I expect the AVP to win, but I’m still leery of DPL II – Music being the equal of TriField.

Saturday I'll be tearing down about a third of the rig to plug in the new preamp.

I expect to be operational by the evening.

Sunday will be measurements and fine-tuning.