Best ML crossover/processor?

Hi ML lovers!

I'm thinking about the best upgrade I could do for my Monoliths, amongst other useful tweaks (passive crossover upgrade, woofer replacement, etc) I think that the best would be going active biamping.

So, looking in the threads, I've seen the (as usual) very valuable comments of Jonathan, but also other members have used some pocessors with good results. The list of suggested equipments in this group is:

1. Driverack 260
2. Driverack 4800 ($!!)
3. Behringer DEQ2496
4. Lake (?)
5. others?

Could you guys give some indications about pro/cons of those gears? For example balanced/unbalanced inputs/outputs (since I do not have other pro-gears, going balanced for me is an addes complication..), and, of course, the final judgement, how they sound!!!

Thanks in advance and greetings from Italy,

Paolo

...3...2...1

It really boils down to:

1. What kind if configuration you need. You will need at least stereo 2 way. Sub sum would be a bonus.
1. How much you are willing to spend
2. What kind of tweekabillity you want.
3. What level of DIY you feel comfortable doing.

The DCX($300) has great potential but out of the box it leaves a lot to be desired in sound quality. After its been modified(+$500) it starts to shine but if you pay someone else to do it can get expensive enough to start looking at the other contenders.

The DBX stuff is very good.
The 260($1000) Stereo 3 way nice piece.
DBX 480 replaced by the 4800 ($5000). Incredible piece 4 in 8 out many different configurations possible.

Rane (400 -- 2000+)
Some say the sound quality is better than the DBX but you'll have to go up to the RPM series to compete on features. RPM 26z is compatible with the DBX 260. Features probably differ.

Ashly ($500 -- 2000+)
Good stuff probably better than Rane.

Lake(10K+) 4 in up to 12 out many different configurations. Unbeatable crossover and EQ filters.

I would summarize this way:

Ignore the Behringer unless you are willing to mod and or must have PC control.

<= $500 Ashly then Rane.
> $500 < 2000 Ashly
> $2000 < $5000 DBX
> $5000 Lake

Hi Pidgi, a timely thread, as ScottGardner and I were exchanging views around the DBX 4800 and the Dolby Lake in another thread. so we'll move that discussion here.

I'm curious to learn more about the Lake as well.

To Scott's excellent list, I'd note the following option in the under $500 range:

The DBX DriveRack PA has most of the features of a 260, but is not PC controllable, fewer EQ options and not quite the same level of audio performance. But for well under $500, it does all the crossover options with enough EQ and delay parameters to make it quite usable for passive crossover substitution.
I believe forum member TedB uses a PA on his Monoliths.

The PA is pretty common and used units on fleaBay are reasonable options.

pidigi said:

...

Could you guys give some indications about pro/cons of those gears? For example balanced/unbalanced inputs/outputs (since I do not have other pro-gears, going balanced for me is an addes complication..), and, of course, the final judgement, how they sound!!!

Thanks in advance and greetings from Italy,

Paolo

Click to expand...

Paolo, interfacing pro-gear is one of the challenges most home audio aficionados will face when doing a speaker processor, but the guidelines are pretty simple.

Here's what I've learned:

Interfacing is much more thean plug compatibility.
- It takes the right impedance matching and level matching to get the best results
- Learn about gain structure and study articles like this one
- Set your gain structure right and maximize the benefits of the gear
- Ground loops happen, that's why God (or Mr. Jensen) invented the isolation transformer. Use them, especially between consumer unbalanced and pro-gear inputs.
- Good quality (but not silly expensive) cables between gear. BlueJeans Cable recommended (and used in my system)

You must have an audio measurment setup to set these up
- Crossovers and speaker / room EQ can NOT be set by ear
- Invest in a good quality Mic and Mic preamp (recommendations later)
- Invest in good Audio measurement software (list of options later)
- Invest the time to learn how to measure and interpret the results. This takes time.


If you set gain structure correctly and have good impedance and electrical matching (no hum), then I believe you can do things that vastly improve (or worsen if incorrectly set) the sound attainable with your speakers in your room.

I found that over 8 years of progressive steps in performing mods to my Monoliths that they got incrementally better, to the point of where Summits were of no interest and even a CLX is more of desire for new tech than a quantum leap for me.

Bottom line, it's not easy, takes lots of effort, lots of boxes, lots of cables and plenty of time to do this. But the results, man the results can be amazing

Before we get too deep into this I should probably say that my music/audio background has been heavily focused more in live /studio than home. This is probably obvious in looking at the crossovers I mentioned --they’re all pro units.

Anyway I don’t have direct experience with the Dolby Lake Processor but I have played with the Lake Contour and I was (we all were) very impressed with its capabilities. Lake products are very unique and not well known. In addition they are expensive so many people feel more comfortable going with a better known company. Maybe now that Dolby has taken them under their wing some of that technology will filter down to the rest of us.

I have heard Bryston mentioned a few times but never heard one. Hmm even thats a pro unit. To be honest I can't even think of a crossover that's not a pro unit. Are there any?

To get some idea of why I'm so enamered with the Lake take a look at these:

You really don have to read if you don't want to the graphs say it all:

The crossover:
http://www.dolby.com/uploadedFiles/...ional/DLP_LinearPhaseCrossoversWhitePaper.pdf

The EQ:
http://www.dolby.com/uploadedFiles/...Professional/DLP_RaisedCosineEQWhitePaper.pdf

You just don't see that any where else... (thats porn to me)

Input side options

Input side options

To match unbalanced consumer gear to pro-audio gear, the following considerations and options exist:

First, you need to go from a unbalanced RCA (cinch) jack on the back of the consumer pre-amp to a balanced line with XLR connectors.

Some gear will claim they work fine with unbalanced inputs on their XLR jacks, and while it might be true that it does work, it is going to be more sensitive to issues than the next option. So you might want to try the some RCA to XLR cable if your gear is known to support the impedances and gain levels of Consumer gear directly.

I tried the above with both the DR 260 and a prior DCX, and in both cases, ground loops, and noise floors were addressed by inserting an Isolation transformer between the Consumer preamp (a Meridian) and the pro-gear.
The input isolation transformer is a 1:1 impedance matching and isolation tool. It also can be the point where you transition from RCA (cinch) connectors to XLR.
The Jensen transformers DM2-RX is the tool of choice here. For ~200 for a stereo box it is super clean, so much so I have three

The ‘cheaper’ alternative is an Art CleanBox, this one is interesting in that it also has a return path from pro-to consumer in the same box.
The downside is that it’s active circuits (opto-isolated, so it does break ground loops) using inexpensive opamps. It also has a high-value (relatively speaking) cap in the output stages that limit frequency response below 30Hz, so not suitable for sub unless modded (details on the mod at Hometheatershack.com)

There are other options, but we can cover those later.

Output side options

Output side options

This one is important when feeding a consumer amp that expects -10dBv levels, vs a pro-gear amp (+4dBv) that expects 14dB more signal.
Often, people just lower the output gain on the processor, but that gives up digital resolution (going from 19 or 20 bits of resolution down to 14 bits or so). Ideally, the output of the processor is at unity or at worse a dB or two one way or the other.

Again, the ideal interface is a Jensen transformer, but this time a step-down transformer is what is used.
The Jensen transformers PC2-XR (XLR in – RCA out) is what I’d recommend.

But ideally, you could find a consumer amp you like that features balanced inputs. Those are pretty common. Just make sure it can take a +4dBv signal. If it can’t, then you still need the step-down or some form of analog attenuation (a 10Kohm in-line attenuator will do the trick).

Jonathan,

Here is a little known easter egg in the 4800. I don't know if it made it into production models but you can check it out easily. With your 4800 connected to your local net startup internet explorer and in the address bar type in HTTP://(its ip address). If this did slip into production you will see a cool little diagnostics page.

Have fun.

JonFo said:

...

But ideally, you could find a consumer amp you like that features balanced inputs. Those are pretty common. Just make sure it can take a +4dBu signal. If it can’t, then you still need the step-down or some form of analog attenuation (a 10Kohm in-line attenuator will do the trick).

Click to expand...

An example is the Sunfire amp, it has XLR balanced in, but can't quite take a +4dBu signal. So I use the slick variable gain structure options in the DR4800 to select the right dBu levels (12dBu in my case vs the 20 it would default to). The DR800 has a bank of realy selectable attenuators vs doing digital scaling. this is much cleaner than the cheaper boxes.

ScottGardner said:

Jonathan,

Here is a little known easter egg in the 4800. I don't know if it made it into production models but you can check it out easily. With your 4800 connected to your local net startup internet explorer and in the address bar type in HTTP://(its ip address). If this did slip into production you will see a cool little diagnostics page.

Have fun.

Click to expand...

Hi Scott, that would have been neat, but I just tried it and it did not work. either they removed it, or it's a setting that's not enabled through SA.

Keep the tidbits flowing :rocker:

Cheers,

ScottGardner said:

To get some idea of why I'm so enamered with the Lake take a look at these:

You really don have to read if you don't want to the graphs say it all:

The crossover:
http://www.dolby.com/uploadedFiles/...ional/DLP_LinearPhaseCrossoversWhitePaper.pdf

The EQ:
http://www.dolby.com/uploadedFiles/...Professional/DLP_RaisedCosineEQWhitePaper.pdf

You just don't see that any where else... (thats porn to me)

Click to expand...

Thanks scott, printed out and off to read in a nice comfortable place with soft music and dimmed lights ....

Yeah, that stuff is porn to me too

Hi Paolo:

I use a Behringer deq2496 and am extremely impressed by the results. The functionality for a $300 unit is incredible and I currently use it to:

- equalize low frequencies (sub 200hz) using the parametric and graphic equalization functions; incredible results!

- boost low frequencies via the dynamic equalization function; a customized and sophisticated loudness "button" which drastically improves the low volume listening experience

- I have had varying levels of success with equalization at higher frequencies, and currently am not using the eq in these ranges. It helped a lot with my old monitor audio speakers but not with my new ones

- Correct equalization of CDs poorly mastered by nearly deaf producers, although the novelty has worn off a bit

The Behringer's DAC is pretty good but can be bypassed if you prefer to use another DAC (although I am still ironing out how to do that most effectively). Some people seem to experience significant distortion with the unit and others, have noted only improvements in the listening experience. My DEQ is noisy using the tape in-out loop but dead silent when connected at the preamp outputs; that may be a problem unrelated to the Behringer.

Given the potential upside with the DEQ for just $300, I think you should spend some time researching this and similar Behringer units at:

http://www.hometheatershack.com/forums/bfd-forum/

Good luck!

I also use the DCX.

Output stage has been replaced with Jan Didden's Passive output mod.
Input stage replaced with direct digital.
Few more mods to go... Clock then power, then...

I've thought about putting some 24db 'U' pads feeding the amps but haven't got a round to yet.

JonFo said:

...

Interfacing is much more thean plug compatibility.
- It takes the right impedance matching and level matching to get the best results
- Ground loops happen, that's why God (or Mr. Jensen) invented the isolation transformer. Use them, especially between consumer unbalanced and pro-gear inputs.
...

Click to expand...

This little device from Jensen takes care of these problems for you:

http://www.jensen-transformers.com/datashts/pc2xr.pdf

Or you can roll your own. The are some App guides and schematics on that site as well.

EDIT: whoops, just noticed JonFo beat me to it...

JonFo said:

...
You must have an audio measurment setup to set these up
- Crossovers and speaker / room EQ can NOT be set by ear
- Invest in a good quality Mic and Mic preamp (recommendations later)
- Invest in good Audio measurement software (list of options later)
- Invest the time to learn how to measure and interpret the results. This takes time.

...

Click to expand...

Here are a couple links to software:

Room EQ Wizard - freeware - works well.
http://www.hometheatershack.com/roomeq/

Smaart - 30 day free trial - Lots of support for pro gear.
http://www.eaw.com/products/software/EAWSmaart/

ScottGardner said:

This little device from Jensen takes care of these problems for you:

http://www.jensen-transformers.com/datashts/pc2xr.pdf

Or you can roll your own. The are some App guides and schematics on that site as well.

EDIT: whoops, just noticed JonFo beat me to it...

Click to expand...

Scott, just want to clear for the others, I'm sure you get this. So bear with me...


The PC2XR is ONLY suitable for matching the Outputs of a pro-gear processor that will be feeding a consumer level input (-10dBv) amplifier.

The PC2R is a Step-Down transformer that takes the +4dBv levels pro-processors have and applies transformer based attenuation.

Very handy for feeding say a sub that does not have Balanced inputs. You get both the step-down and the isolation (no hum) benefits.

thanks!

Thanks for you help!

First of all, as you have seen, I'm quite busy so my reaction time is often quite slow....

First of all it seems that good results can be obtained with Behringer units, but stock units are not in the same league, sound quality speaking, of other options that Scott and Jonathan have suggested. Behringer here is quite popular and cheap, I actually could do some tweaking by myself but (see above) time is here often priceless. Anyhow, this could be a future upgrade (hey, if I reach now the audio nirvana which will be in the future my upgrade path?)
What about features? Do you think that the Behringer has all the needed handles to squeeze out the best from my Monoliths?

Then the interfacing problem. I completely agree that using an isolation transformer will take rid about ground loops, and this is absolutely necessary in the pro field and also for you Jonathan, the pictures of your electronic rack are impressive! I'm wondering if, in a simple installation as the one that I'm going to setup, the isolation benefits would really outperform the disvantages. Yes, I don't believe anymore that there is a free lunch! Apart from gain balanced and isolation matters, do this isolation transformers degrade somehow the sound quality? Two of them should be installed, so this is something that starts worrying me, if there actually is a sonic degradation, even if very small, would this degrade the overall performance and then put the processor system at the same level as a theoretically inferior competitor? From what you say I can argue that this is not the case, is it?

Software: I've had a quick glance at REW, seems to me that if you don't have a compatible sound processor the only advantage that it would have against my CLIO measuring system is the graphical utility to create an equalization curve. Am I right?

Ciao!

Paolo

pidigi said:

What about features? Do you think that the Behringer has all the needed handles to squeeze out the best from my Monoliths?

Click to expand...

The Behringer is a good unit but you will (probably) notice grain in the highs without mods. But hey you can get a new one on eBay for about $250 and see. If you don't like it you can sell it on eBay and your net cost for the experience would be around $100 or less.

Features wise it is an unbelievable unit.
Digital 24/96 AKM D/A
Dynamic PEQs
Input delays, PEQ's,
Output PEQs, Limiters, Delays, Phase control
Auto-align
PC Control.

Then the interfacing problem. I completely agree that using an isolation transformer will take rid about ground loops, and this is absolutely necessary in the pro field and also for you Jonathan.... do isolation transformers degrade somehow the sound quality?

Click to expand...

Only if you use cheapies. The Jensen’s don't have this problem when used properly.

Two of them should be installed, so this is something that starts worrying me, if there actually is a sonic degradation, even if very small, would this degrade the overall performance and then put the processor system at the same level as a theoretically inferior competitor? From what you say I can argue that this is not the case, is it?

Click to expand...

Not sure what you mean by two of them. You would use one per line. The units from Jensen will handle two lines.

If you're takling about one for the input and one for the outut then yes you would need 2. Ideally you will feed the Behringer digitally because the stock analog inputs aren’t so great. Plus if you can avoid an D/A->A/D stage you're better off.

You don't need transformers if your ICs are short. 'U' (balanced) or 'L'(unbalanced) pads can be used. These Pads are just resistors. Use of high quality resistors will have less effect on the signal than the transformer units (they have resistors in them too).

Software: I've had a quick glance at REW, seems to me that if you don't have a compatible sound processor the only advantage that it would have against my CLIO measuring system is the graphical utility to create an equalization curve. Am I right?

Click to expand...

CLIO? I don't know what that is.

To properly setup any crossover you will need to send pink noise or some other known frequencies through it. Then measure and adjust EQ's to smooth out the response. These visual tools will generate pink noise and allow you to see EQ changes in real-time. If the visual tool also allows you to adjust EQ or other XO settings then everything is easier but not necessary.

The Behringer also has an Auto-align function that will automatically measure and adjust delays to compensate for woofer/panel alignment. Without this you would need to measure and adjust delays using a tool that allows you see the frequency response with at least 1/3 octave resolution .