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Quote:
Originally Posted by TEL79 /forum/post/14038040


You can use Audyssey for the speakers, but it's a bit questionable if it will improve the system or actually make it worse. Due to tests, Audyssey in even some more expensive receivers (~2000e) does not even touch the response of the subwoofer, only speakers.

A lot of conclusions (about many products) are based on less than successful use of them. Note the long 'official' thread on Audyssey to show the intricacies of getting it right. Similarly, I am wrestling with the ARC in an Anthem D2 and it, too, is far from 'plug-and-play.'

Quote:
Using EQ to higher frequencies is not particulary effective, as the response and sound characteristic are changing very position dependent. Even inches away from measurement point will make dramatic changes.

This is worse for bass and a poor argument for not EQing higher up. At higher frequencies, the density of modes, spatially and in frequency, is higher, making positioning less critical than for bass (or mid-bass).

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Forcing a flat response up from 200Hz may result in sound image that sounds colored and simply wrong. I would recommend to use the Audyssey only to measure speaker distances and volume, not EQ or "Dynamic EQ" which only adds more distortion to the signal (dynamic loudness). This is what people using both Audyssey and AM has concluded to do, and it works great.

Well, I have not had a chance to play with the 8033 yet but I believe most people who have the opinion that Audyssey or other EQ products, used correctly(!), colors the sound have simply adapted to the colorations of their room/speaker and base their preference on that adaptation. Now, if you have a well-designed and acoustically treated room, as well as good, well-positioned speakers, the effect may be minimal but it always helps. (Again, when done right.)
 

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Quote:
Originally Posted by Kal Rubinson /forum/post/14038571


Do you think that modes are a problem only at the fundamental frequency of the primary room dimensions?

You are right, I didn't think of that as I was only thinking about subwoofers.


You would then need to have eq above the crossover frequency with the main speakers too, but still limit the correction to the 'bass range' to avoid problems with the locality issuescaused by the correction (which isn't a problem with the mono subwoofer channel).
 

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Quote:
Originally Posted by Kal Rubinson /forum/post/14038620


At higher frequencies, the density of modes, spatially and in frequency, is higher, making positioning less critical than for bass (or mid-bass).

Doing EQ for the higher frequencies is OK as long as you dont try to make too narrow high-Q correction filters based on one point. At this side of the Schroder radius, modal peaks and nulls can have bandwidth of only few hertzes (no smoothing), and the center frequency is altered by same amount when microphone is moved a few inches to any direction. They would correct the response very locally. Automatic EQ algorithm for higher frequencies must be done with different approach to obtain successfull results. You can use for example shelving filters and wideband bandstops, and the measurements can be taken from many points to get better view of the situation (and avoid early reflection errors). The algorithm computes smoothed versions of responses and combines the multiple point data in different way compared to bass range, where also the absolute phase information is important (for algorithm).


The measurement routine is also different for higher frequency automatic EQs to work properly. You can measure the speaker itself with very short MLS burst, speaker with early reflections with a bit longer one, and late reverberation decay characters (waterfall time curves) of the room with long windowed MLS or sweep. If done right, automatic EQ can indeed improve higher frequencies too. The effect might not be as obvious as it is in the bass range with severe modal problems. I guess I'm personally favoring treatment over EQ on the higher frequencies.


But it is true, that even the best systems can and will fail if the user don't know how to use them.


In the test (Finnish Hifi-world 2/08) I mentioned between YPAO, Audyssey and MCACC, it was Audyssey (in Onkyo TX-SR875E) and MCACC (in Pioneer VSX-LX70) that resulted in better response measurement-wise, but they were considered subjectively worse. YPAO (in Yamaha RX-V3800) made only slighter adjustments, and was subjectively considered best by the professional testing crew. This supports my opinion of EQing higher response, optimising the result for a standard MLS or sweep measurement is not the best option. It should also be noted, that none of them corrected the subwoofer response properly, where the most benefits of PEQ would have been.
 

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Quote:
Originally Posted by Mupi /forum/post/14035799


I was wondering how it corrects the decay time. I was under the impresion that decay time/reverb can be best correctted by using room treatments (bass traps/absorbers)


I have used BFD (DSP1124P and FBQ2496). I dont like these for the fact that they add significant distortion when passed a full range signal. The distorsion is not as much when passed the low frequency alone but I am a bit hesitant to use them because of their impact on sound quality.


I have added corner bass traps to my room. Though the FR as not changed significantly except the peak at 142Hz the boominess is not there as much. I sit right at the back wall. Attached is the FR before and after bass traps. it is not in log scale. never mind.


Like I said the peaks and nulls have not improved but the decay time has probably improved. I dont know how to make the waterfall plots to see if the decay time/reverb has improved but I can hear the difference.


Now my question is: will the 8033 improve that nasty curve at my listening position


Please ignore that black frame. That is not part of the bass trap.


Just wanted to clarify that this is not just the bass response. I have not set the cross over high. My sub (Sunfire True Sub Junior) can only go upto some 100Hz. Its specs are 22-100Hz. The cross over is set at 90Hz. I have an old Yamaha RX-V795a and it has just one cross over at 90hz. No options.


The FR is for the mains and sub combined. Mains are set to small.


The nasty peaks beyond some 90Hz or so are mainly due to the mains.


I have one important question. Does 8033 accept full range signal or does it acept only below 80Hz. I guess the SVS EQ only accepts 80Hz and below no matter what I feed. If that is the case with 8033 then it will be useless to me

because I have some nasty peaks over 80Hz that I need to tame down.

I can only do this by sending full range signal as my receiver has fixed cross over at 90Hz and also my sub can only play up to some 90Hz.


Like I said before I can feed the BFD FBQ2496 full range and use its 20 filters to get a decent response up to 200Hz. But the FBQ2496 causes significant distortion to the high frequencies even if they are not EQ-ed. Just passing the full range to the BFD causes distorsion to the signal. The distorsion is not noticable at low frequencies. It is not an audiophile quality devide. Mainly mean for PA systems I guess.


So how does 8033 handle full range signal?
 

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Quote:
Originally Posted by Mupi /forum/post/14040339


Just wanted to clarify that this is not just the bass response. I have not set the cross over high. My sub (Sunfire True Sub Junior) can only go upto some 100Hz. Its specs are 22-100Hz. The cross over is set at 90Hz. I have an old Yamaha RX-V795a and it has just one cross over at 90hz. No options.


The FR is for the mains and sub combined. Mains are set to small.


The nasty peaks beyond some 90Hz or so are mainly due to the mains.


I have one important question. Does 8033 accept full range signal or does it acept only below 80Hz. I guess the SVS EQ only accepts 80Hz and below no matter what I feed. If that is the case with 8033 then it will be useless to me

because I have some nasty peaks over 80Hz that I need to tame down.

I can only do this by sending full range signal as my receiver has fixed cross over at 90Hz and also my sub can only play up to some 90Hz.


Like I said before I can feed the BFD FBQ2496 full range and use its 20 filters to get a decent response up to 200Hz. But the FBQ2496 causes significant distortion to the high frequencies even if they are not EQ-ed. Just passing the full range to the BFD causes distorsion to the signal. The distorsion is not noticable at low frequencies. It is not an audiophile quality devide. Mainly mean for PA systems I guess.


So how does 8033 handle full range signal?

8033 is meant for only subwoofer, so you cant EQ mains with it. The device has a built-in lowpass at D/A side which will filter out above 160Hz. The range of correction is limited to 16-144 Hz, as this is the region when Anti-Mode algorithm can be used. Above that, AM type automatic algorithm can not be used because of phenomena relating to modal density and Schroder radius.


Unfortunately in your case, the 8033 can not help above to fix above 90 Hz if the cross over is fixed to this frequency.
 

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Quote:
Originally Posted by TEL79 /forum/post/14040502


8033 is meant for only subwoofer, so you cant EQ mains with it. The device has a built-in lowpass at D/A side which will filter out above 160Hz. The range of correction is limited to 16-144 Hz, as this is the region when Anti-Mode algorithm can be used. Above that, AM type automatic algorithm can not be used because of phenomena relating to modal density and Schroder radius.


Unfortunately in your case, the 8033 can not help above to fix above 90 Hz if the cross over is fixed to this frequency.

My LFE cross over is fixed at 150hz, so I expect help with that.


Bill
 

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Quote:
Originally Posted by TEL79 /forum/post/14040281


Doing EQ for the higher frequencies is OK as long as you dont try to make too narrow high-Q correction filters based on one point. At this side of the Schroder radius, modal peaks and nulls can have bandwidth of only few hertzes (no smoothing), and the center frequency is altered by same amount when microphone is moved a few inches to any direction. They would correct the response very locally. Automatic EQ algorithm for higher frequencies must be done with different approach to obtain successfull results. You can use for example shelving filters and wideband bandstops, and the measurements can be taken from many points to get better view of the situation (and avoid early reflection errors). The algorithm computes smoothed versions of responses and combines the multiple point data in different way compared to bass range, where also the absolute phase information is important (for algorithm).

Agreed.

Quote:
The measurement routine is also different for higher frequency automatic EQs to work properly. You can measure the speaker itself with very short MLS burst, speaker with early reflections with a bit longer one, and late reverberation decay characters (waterfall time curves) of the room with long windowed MLS or sweep. If done right, automatic EQ can indeed improve higher frequencies too. The effect might not be as obvious as it is in the bass range with severe modal problems. I guess I'm personally favoring treatment over EQ on the higher frequencies.

I won't tell anyone.


Quote:
But it is true, that even the best systems can and will fail if the user don't know how to use them.


In the test (Finnish Hifi-world 2/08) I mentioned between YPAO, Audyssey and MCACC, it was Audyssey (in Onkyo TX-SR875E) and MCACC (in Pioneer VSX-LX70) that resulted in better response measurement-wise, but they were considered subjectively worse.

Well, I do not have access to that report nor have I used any of the EQs except Audyssey, and that in other equipment. The mic Onkyo uses for this is, imho, a poor design that makes getting correct measurements very tricky. OTOH, when it comes to subjectivity, that's a bigger can of worms.
 

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Quote:
Originally Posted by Kal Rubinson /forum/post/14042123


I won't tell anyone.

Thanks


Quote:
Originally Posted by Kal Rubinson /forum/post/14042123


Well, I do not have access to that report nor have I used any of the EQs except Audyssey, and that in other equipment. The mic Onkyo uses for this is, imho, a poor design that makes getting correct measurements very tricky. OTOH, when it comes to subjectivity, that's a bigger can of worms.

It's true, subjectivity plays a big part at higher frequencies. It's difficult if not impossible to make a full-band auto-EQ that would satisfy everyone. Like you thought earlier, it's even probable that the listener gets accustomed to the anomalities and coloration of the room, and the corrected sound balance then feels too weird. In the bass range there is much better consensus of what sounds right, or at least what sounds wrong. Nearly all people appreciate getting rid of the boomy modal peaks.


This is one of the differences when designing automatic algorithms to clean bass range vs. other freqs. In the bass, you can actually counter-model the room accurately with DSP, even if the best results apply with local nature. But at the higher frequencies the accurate response in both frequency (and digital z-domain) and time domain is actually changing even more rapidly from point to point. However, what virtually remains the same on higher frequencies is the "envelope" of the spectrum, which can be tweaked to get better response. I assume this is the property you meant when you stated that the response at higher frequencies has globally more consistent nature. There, at higher the best DSP-correction model is stochastic, compared bass frequencies where exact z-domain countering can be used.


There are some semi-stochastic approaches to bass EQ as well in the previous equipment, for example Velodynes SMS-1. It uses heavy smoothing (1/3 or 1/2 oct) in the measurement it can plot to TV. However that is also perhaps the main reason why it's automatic EQ algorithm falls kind of short. That and 1Hz resolution it uses which is simply not enough. You'd get better results with it (or much better with BFD etc.) when you manually set the filters with computer based measurement software such as Room EQ wizard, because that way you get closer to the exact counter-model of the room. Also the price in Europe for SMS-1 was maybe too high for wide commercial success (>800e). SMS-1 had it's own good properties like the ability to use it as cross over and the remote controller.


With 8033 the motivation was to make precise auto-EQ (improved spectral resolution, 24 filters, 4-phase iterative measurement, wider area compensation) which everyone can use and the price would still be the same as with manual PA EQs + microphone + accessories. I think this is one of the main reasons 8033 became so popular immediately after it was released (first production lot was sold out in 2 days), and the fact no one likes boomy modes.
 

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I do not think we are disagreeing much about any of this. Ideally, all would be resolved with physical acoustical treatments which, afaik, have no downsides, other than cost and bulk. Short of that, one needs to handle low frequencies somewhat differently from the way we deal with high(er) frequencies. The only complication I was trying to emphasize is that subwoofer EQ is constrained by the fact that our upper limit for reasonable crossover frequency (to avoid obvious localization) is an octave or two lower than the Schroder limit. That leaves, to me, a glaring gap in the most critical range, one that affects voice timbre. I do not have a good off-the-shelf solution for that, other than a Rives PARC for each pair of main channels and a sub-PARC (or 8033 or other bass EQ) for the woofer(s).
 

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Quote:
Originally Posted by Kal Rubinson /forum/post/14044143


That leaves, to me, a glaring gap in the most critical range, one that affects voice timbre. I do not have a good off-the-shelf solution for that, other than a Rives PARC for each pair of main channels and a sub-PARC (or 8033 or other bass EQ) for the woofer(s).

Yep, I know what you mean.


It is possible that maybe one day in the future there will be consumer priced full-band EQ/Cross-over device from VLSI Solution's DSPeaker product series. But for now, theres the 8033 Anti-Mode for subwoofer and a couple of other new DSP products. The 8033AM seems to be helping a lot of people struggling with bad bass response. As far as I know, it is also the only plug 'n play auto-EQ in it's price range.


As with any EQ, the improvement on 8033 depends on how bad the initial situation was. In really good listening rooms the improvement is noticeable but subtle, whereas in other rooms the improvement is unbelieveable. As the old say goes: If it's not broken, don't fix it.


Here's one room from the days of 8033s development era, which was definitely broken. The CSD graphs f-axis has linear scale, because it suited much better for development purposes back then. The sub was placed in corner (best position for 8033 algorithm)


The room before:



and the same room after automatic calibration of 8033



I just hope that some customers of 8033 can have as 'bad' room as that was, so that they can have the same feeling that I had when I listened the difference.
 

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Are you guys saying that there is really no great full range active crossover/EQing solution out there at a reasonable price?


I have been searching for this solution lately because Im building full range 3-way speakers that will have active crossovers.



BTW, any updates on the 8033?
 

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The cheapest one dip / bump solution is a plate amp with built in EQ.



I have had good success with this in most rooms. Not a full featured EQ solution by any means, but pretty darn effective none the less.
 

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Quote:
Originally Posted by penngray /forum/post/14045299


Are you guys saying that there is really no great full range active crossover/EQing solution out there at a reasonable price?

That depends on what you regard as reasonable. IMHO, no.
 

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That depends on what you regard as reasonable. IMHO, no.

Same price range (under $500), right now it seems my top option is the Behringer DCX2496 which I can buy for around $200 and it has a very respected following.


I just was reading this thread and I wanted more details on the above option.
 

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I was wondering if it is possible to create the waterfall plot

uisng REW (Room EQ wizard) or any other free softwares,

from the FR plot. i.e I have the FR plot (db vs Hz) and from that

can I create the decay plot. I read that it is possible to convert the waterfall

plot to FR plot uisng fourier transformation (which is built into those free softwares). But I dont know if the inverse is true. i.e can I create the waterfall plot from the FR plot. If not, is there an easy way to create the waterfall plot and what kind of measurements I need. Looking at the REW, it seems like I need to measure the response due to an impulse but I dont know how to do that. All I have right now is the Radio Shack SPL meter.

Are there test tones that I can download to create the waterfall plot?
 

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REW has the waterfall charts in it already I dont know if you can import a FR plot and create a waterfall chart. REW needs to actually have all the room measurements run with in it.



I couldnt wait any more I just ordered the Anit-mode
 

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Quote:
Originally Posted by thsmith /forum/post/14025947


Bill, I too am interested in your results, as you know I have 3 3 T and MBM and I know you have mutiples of both. Your experience and how to deal with more than 1 sub will be interesting.


As usual thanks for blazing a trail.


Tracy

Installed Anti Mode 8033B today and WOW what a difference and I'm running two MBM-12's (one with each main with xover of 100hz), and two HSU 3.3's. It is worth the $$$$$. Make sure you follow the directions and you will have no problems. I'm running it "flat" with no "lift" and it has the WOW factor. No upgrade needed for a couple of years for this boy. My system sounds like it is new and different and it is a joy to watch movies all over again.


Bill
 

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Quote:
Originally Posted by Archbushman /forum/post/14050556


bsoko,

Do you have any room treatments? (bass traps?)

NONE! The space is over 6000 cu ft and has 2 large openings on the left side to other parts of the house.


Bill
 

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Quote:
Originally Posted by bsoko2 /forum/post/14050290


Installed Anti Mode 8033B today and WOW what a difference and I'm running two MBM-12's (one with each main with xover of 100hz), and two HSU 3.3's. It is worth the $$$$$. Make sure you follow the directions and you will have no problems. I'm running it "flat" with no "lift" and it has the WOW factor. No upgrade needed for a couple of years for this boy. My system sounds like it is new and different and it is a joy to watch movies all over again.


Bill

Excellent news Bill. After you have had a couple of days listening could you come back with some details on the improvements you have seen.


I assume I would run an RCA cable from AVR to 8033 the y cable out of 8033 to 3 3 and MBM? 8033 and AVR would be co-located?
 
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