[MGbert]

Im still a bit confused about the AD conversion. Why not just sent a digital signal to the dsp and let it do the conversion to analogue. Skip one step.

Until this week, that is exactly what I did.  I just took delivery of a Parasound Zdac to see if a new generation DAC would be an improvement on the Behringer's DAC.  Besides, the Zdac has a fairly nifty headphone amp built in, which scratches another itch.

MGbert

[MGbert]

Yep, I understand.  Screen 1 with the PEQ button pushed should show your overall EQ settings.  (I'm assuming you used the PEQ capability and not the GEQ.)

Also, one of the users on DIYaudio a number of years ago wrote a handy Windows utility that will allow communication via the MIDI connections on your unit.  One of the features is allowing to capture the current screen on the DEQ front panel and save to the clipboard.

http://www.diyaudio.com/forums/digital-line-level/53088-deq-2496-remote-controll-under-construction-myself.html

Cheers,

Dave.

Thanks; I'll have to check that utility out.  I guess I'll need a MIDI-to-USB cable.

Actually, I use the GEQ for room response EQ.  Once the room response is suitably flattened, then I superimpose PEQ settings as a "house curve" which tilts the FR so bass and midrange is a few dB louder than treble.  Also add the so-called "BBC dip" around 2500 Hz.  There are occasional recordings (like soundboard recordings, interestingly enough) which do not need the house curve at all, and some others need some HC parameters reduced.

Found the camera; need batteries.  Always something...   

MG-bert

[SteveFord]

They're in Keith Jarrett's trouser pockets.
He also took your Miles Davis albums...

[pansixt]

What, no track listings?  What you remember hearing that "grabbed" you?

Yep,
I requested the Sara K track Miles Away a second time because the sonics were awesome, but the tracks I felt the most
were from Dave Brubeck Live at Carnegie Hall. The musicians were clearly defined on stage on that one.

Thanks for asking. Obviously my reviewing sucks. Have no pictures and little track list.

[MGbert]

OK, here are pictures of the configuration in my shed as well as readouts from the Behringer.

First the electronics:



and a pic of the right MMG and FRT:



The layout of the room and the FRTs is covered in this thread:

http://www.audiocircle.com/index.php?topic=118512.new#new

but, at the risk of duplicating the image, here is the floor plan:



Now for the Behringer data.  Here is the non-equalized response of averaged pink noise:



Each bar represents the volume of 2 adjacent musical notes (6 bands per octave, 12 musical notes per octave).  Note the suckout at 80 Hz, the large midrange hump and a treble peak.  After subtractive equalization using the GEQ (30 band graphic equalizer) here is the flattened response:



and the GEQ settings which accomplished the minor miracle of getting the response within +/-2.5 dB from 40 Hz to 14KHz:



Yeah, some frequencies need to be cut by as much as 12 dB.

I mentioned the "secret sauce" of a house curve.  I use the PEQ (parametric equalizer) function of the Behringer to create this subtle curve:



Note the bass bump around 50 Hz, a gradual bump in the bass and lower midrange, the so-called "BBC dip" around 2500 Hz, and a gradual reduction of the treble frequencies.  These can easily be tweaked in real time based on how any given recording sounds.  The Chesky disk referred to earlier and soundboard recordings actually sound best without any PEQ.

Did I say the net result of all this work sounds really great?   

MGbert

[jult52]

MGbert - sounds like a nice listening session.  As a fellow gunn'd MMG owner, I have one piece of advice and then a question:  I urge you to halfRazor your MMGs.  It's cheap and easy - under $35 and an hour of work.  Your bass response will improve, as will the purity and density of the timbres produced. 

Now the question: what is the sonic effect of raising the MMGs by a foot?  I assume you are sitting at a normal height when listening to the speakers.

[Davey]

You have a fairly considerable dip programmed through the midrange on the speakers.  This looks consistent with what I'd expect (and what I experienced) from the Magnestand crossover.

Under anechoic conditions the Magnestand speakers would measure with a broad hump through the central region of the audio band.

Cheers,

Dave.

[jk@home]

Hey MGbert.  If your main source is regular CD/rips, you can improve that by installing a Behringer SRC2496 in front of the DEQ to upsample. They really go great together as a pair. The SRC can also be used as a source selector. I found improved resolution when I added that to my system (which is MMGs w/ the PG series x-over).

Also it may help to place a DIP ( I use an old Monarchy DIP 24/96) between the DEQ and DAC, to clean up, isolate and buffer the digital signal. I use a good quality optical cable between DEQ and DIP, which electrically isolates also. I found an outboard DAC did give an improvement over the built in one in the DEQ.

[MGbert]

Hey MGbert.  If your main source is regular CD/rips, you can improve that by installing a Behringer SRC2496 in front of the DEQ to upsample. They really go great together as a pair. The SRC can also be used as a source selector. I found improved resolution when I added that to my system (which is MMGs w/ the PG series x-over).

Also it may help to place a DIP ( I use an old Monarchy DIP 24/96) between the DEQ and DAC, to clean up, isolate and buffer the digital signal. I use a good quality optical cable between DEQ and DIP, which electrically isolates also. I found an outboard DAC did give an improvement over the built in one in the DEQ.

Hey jk:

Thank you for the recommendations.  A few questions, though: 

1) given that the Parasound has an upsampler already, why would I need the DIP between it and the Behringer?

2) Are you saying that the SRC would improve things by upsampling the Oppo's digital output before it hits the DEQ?  That upsampling should occur before each additional step in a digital "daisy chain"?

3) Most importantly, for me, will be to inject analog output (turntable, tape deck) into the Behringer DEQ, since I can't imagine doing without the room EQ.  The output from my Musical Fidelity phono preamp is a bit low, so I'm sure I'm taking a hit on fidelity if the loudest signal hitting the ADC is -15 bd.  If worst came to worse, I do have analog equalizers which I could use with the analog gear, calibrating them with the DEQ's RTA as equalizers or just passing the phono preamp's signal through flat but amplified.  But I'd rather just have analog be an additional input to the DEQ.  I have tried the DEQ's analog to digital converter (ADC) before, and it seems at least adequate; does the SRC happen to have an improved ADC to bring to the table?

And, does anyone have a recommendation for a better ADC than the one built into the DEQ 2496? 

I realize this might be veering into Discless Circle territory here, so maybe responses by PM would be better?  I'll let Steve figure that out.     At any rate, thanks for the input!

MGbert

[MGbert]

You have a fairly considerable dip programmed through the midrange on the speakers.  This looks consistent with what I'd expect (and what I experienced) from the Magnestand crossover.

Under anechoic conditions the Magnestand speakers would measure with a broad hump through the central region of the audio band.

Cheers,

Dave.

Hey Davey:

Exactly what I figured.  Goes to show that, even if a speaker isn't the last word in linearity (for whatever reason; I'm perfectly willing to blame my shed for a part of this) but gets transient response and other aspects right, then correcting for the response flaws are like opening a curtain.  Or, since Josh358 likes to say that Maggies present a slightly dirty window on the performance, think of the Behringer as a bottle of Windex and a cloth.  Afterwards, it lets in more "light".   

MGbert

[MGbert]

MGbert - sounds like a nice listening session.  As a fellow gunn'd MMG owner, I have one piece of advice and then a question:  I urge you to halfRazor your MMGs.  It's cheap and easy - under $35 and an hour of work.  Your bass response will improve, as will the purity and density of the timbres produced. 

Now the question: what is the sonic effect of raising the MMGs by a foot?  I assume you are sitting at a normal height when listening to the speakers.

jult52:

I know, I know, the "half razor" has been on my todo list for a few years now...

For the unitiated, here is a link to the flavors of "Razoring", which has nothing to do with cutting the mylar   

http://www.audioasylum.com/cgi/t.mpl?f=mug&m=155318

And by raising and shimming the back spikes, the MMGs are now almost straight up with the middle of the panel at ear level.  I have tried listening to them "as pgunn" intended, on the floor with no shimming to straighten them, and did not like how low the soundstage was relative to the floor.  Also, I find a small angle to be preferable to "straight up"; not sure why that is, but it just goes to show that tilt is yet another variable to test.   And raising the MMGs, in my room (always have to put in that disclaimer!) had little effect on the amount of bass necessary for musical believability, as can be seen by the FR plots posted above.  In other words, if there was more bass, I'd just have to attenuate it more.   

Interestingly enough, I got to audition JansZen zA2.1 speakers at the Capital AudioFest this weekend, which are also short planars tilted a la pgunn, and got none of the "performers in an orchestra pit in the floor" effect.  That might be because the JansZen takes great pains to trap the rearwave inside the cabinet totally, whereas the MMGs don't. 

MGbert

[Woo37830]

If u go to Home Depot,
U will find
1/4 x 20 x 70 mm connecting bolts
Part # 53954 in furniture & cabinets, fasteners

Except for not being beveled, the work perfectly as the eight corner bolt replacements

Also, the have 5/16 dowels cut to perfect length

[jk@home]

Hey jk:

Thank you for the recommendations.  A few questions, though: 

1) given that the Parasound has an upsampler already, why would I need the DIP between it and the Behringer?

2) Are you saying that the SRC would improve things by upsampling the Oppo's digital output before it hits the DEQ?  That upsampling should occur before each additional step in a digital "daisy chain"?

3) Most importantly, for me, will be to inject analog output (turntable, tape deck) into the Behringer DEQ, since I can't imagine doing without the room EQ.  The output from my Musical Fidelity phono preamp is a bit low, so I'm sure I'm taking a hit on fidelity if the loudest signal hitting the ADC is -15 bd.  If worst came to worse, I do have analog equalizers which I could use with the analog gear, calibrating them with the DEQ's RTA as equalizers or just passing the phono preamp's signal through flat but amplified.  But I'd rather just have analog be an additional input to the DEQ.  I have tried the DEQ's analog to digital converter (ADC) before, and it seems at least adequate; does the SRC happen to have an improved ADC to bring to the table?

And, does anyone have a recommendation for a better ADC than the one built into the DEQ 2496? 

I realize this might be veering into Discless Circle territory here, so maybe responses by PM would be better?  I'll let Steve figure that out.     At any rate, thanks for the input!

MGbert

Hey MGbert

I placed the DIP between the DEQ and my Channel Island DAC. This allows me to isolate the Behringer stuff with an optical cable into the DIP, and then run a long (3 meter) coaxial from the DIP to the DAC. Not about upsampling, more about cleaning and boosting the digital signal. From inside a closet to between the speakers (for shorter analog cables downstream).

Don’t need to upsample on every piece, if the new Parasound unit is doing it, you are good. AFAIK, the A/Ds and D/A in the SRC is the same as in the DEQ. Some maybe you don’t need it.  The Channel Island I use doesn't have upsampling.

I do run one analog source into the SRC. I have one of those Sony mini tuners that were all the rage a few years back. I send it’s signal to a Bottlehead SEX headphone amp, which then boost the analog signal up for the“pro”level inputs of the SRC. But I don’t consider that a critical source so no sleep is loss regarding the A/D conversion. I have read of other folks using this setup with LPs, so you may be fine with it. You may need to buffer the LP signal up for your DEQ's A/D, with another preamp or something which would add more stuff in the chain (usually not good).

Hey if Steve can talk about his snakes...ewww! (jk Steve), anything goes here. 

[Davey]

Hey Davey:

Exactly what I figured.  Goes to show that, even if a speaker isn't the last word in linearity (for whatever reason; I'm perfectly willing to blame my shed for a part of this) but gets transient response and other aspects right, then correcting for the response flaws are like opening a curtain.  Or, since Josh358 likes to say that Maggies present a slightly dirty window on the performance, think of the Behringer as a bottle of Windex and a cloth.  Afterwards, it lets in more "light".   

MGbert

I wouldn't characterize the Magnestand response as "flawed".....just different relative to the stock configuration.  Who are we to say whether flat anechoic response should be the objective for this speaker or any other?

However, I do find it interesting that you've somewhat "undone" the Magnestand crossover alignment to achieve your preferred setup. 

I'm glad to see more experimentation with DSP gadgets like the DEQ2496.  These can be excellent tools to make significant changes/improvements to in-room responses.

Cheers,

Dave.

[MGbert]

I wouldn't characterize the Magnestand response as "flawed".....just different relative to the stock configuration.  Who are we to say whether flat anechoic response should be the objective for this speaker or any other?

However, I do find it interesting that you've somewhat "undone" the Magnestand crossover alignment to achieve your preferred setup. 

I'm glad to see more experimentation with DSP gadgets like the DEQ2496.  These can be excellent tools to make significant changes/improvements to in-room responses.

Cheers,

Dave.

Actually, the main charm of the PG crossover, IMHO, is the way it apparantly "smears" the high frequencies over the entire panel, so that when you listen near field you are not listening to a distinct QR tweeter and a mid/bass driver, but a full range transceiver.  That in itself is quite a benefit, and I was going to use EQ as room correction anyway.  It does make a lot of sense (to me, anyway) to first get the FR as flat as possible at the listening position, then sculpt the "house curve" so that your speakers have the response YOU want, vice what the speaker designer (or in my case, modder) decided what would sell product.  As long as the speaker gets PRAT, clarity, and dynamic transient response right, of course.   

MGbert

[MGbert]

If u go to Home Depot,
U will find
1/4 x 20 x 70 mm connecting bolts
Part # 53954 in furniture & cabinets, fasteners

Except for not being beveled, the work perfectly as the eight corner bolt replacements

Also, the have 5/16 dowels cut to perfect length

@Woo37830:

did you mean to post this elsewhere?   

MGbert

[Davey]

The blending of the drivers into one with that crossover is strictly a result of the switch to first-order slopes and raising the LP cutoff point and lowering the HP cutoff point.
There is already a "mechanical" crossover associated with the MMG panels even before capacitors or inductors are added.  The different electrical alignment just accentuates that blending.
However, regardless of how you blend the drivers in this way....with either a parallel or series crossover, the acoustic response becomes non-flat.  It's impossible to not yield that result.
Your solution to flatten the humped acoustic response with electronic equalization is perfectly acceptable.  Other than reversing the crossover modification back to stock component values, it's the only way to return the speaker to flat acoustic response.

Cheers,

Dave.

[bdp24]

MG---The common wisdom in hi-fi holds that upgrading a system should begin with the source, then to the amplification, and lastly to the speakers and the room, that downstream components can reproduce only that which they are fed from further upstream, that more transparent speakers will more readily reveal flaws in the gear proceeding them. Why did you start at the end of the chain?

[Davey]

I think that's a case where the common wisdom is not very wise. 
You should always upgrade the weakest link in the audio chain first.  The speakers are almost always this link and they should be attended to first.  There are plenty of decent electronics and source equipment nowadays, but an audiophile can really get a system horribly wrong by selecting the wrong speakers.

Cheers,

Dave.

[ebag4]

I think that's a case where the common wisdom is not very wise. 
You should always upgrade the weakest link in the audio chain first.  The speakers are almost always this link and they should be attended to first.  There are plenty of decent electronics and source equipment nowadays, but an audiophile can really get a system horribly wrong by selecting the wrong speakers.

Cheers,

Dave.

x2