equalizer question

[hankdog]

I'm thinking of using an equalizer in my system, read the article about using rives audio cd and want to try an eq ,am looking at the art 351[in the article they used a 352 ]or might try a rane sse35, my system consists of a yamaha rxv2500 klipsch rf35 floorstand speakers rc35 center rs35 surrounds and 2 rw12 subs and the room is 14x20 with a 15 foot peak in the ceiling. It sounds very good but want to make it better any advise would be great. thanks.

 

[Buckle-meister]

Welcome to the Forum Hankdog.

I'm thinking of using an equalizer in my system...

I can't speak from personal experiance since I do not (yet) use equalisation, but a fellow member, WmAx, a person you would do well to heed, has time after time recommended the Behringer DCX2496 as a superb parametric equaliser. Bear in mind though, that it is a professional piece of gear, so some slight modifications would be required to integrate it into your consumer audio system.

...my system...sounds very good but want to make it better any advise would be great.

I would recommend pursuing room treatment before equalisation. In my opinion, equalisation should be considered only as a means to ‘tweak’ a room’s response because:

1. Equalisation won’t help reduce comb filtering in a room.
2. Equalisation targets one specific location only. Consequently, whilst the frequency response at that location may be improved, other locations may have been made worse.
3. Equalisation is typically used only to lower peaks, rather than raise nulls in the frequency response, yet the latter are usually far greater in amplitude, and therefore more damaging to sound quality.
4. A passive solution (room treatment) is always preferred over an active solution (equalisation).

Regards

 

[WmAx]

[*]A passive solution (room treatment) is always preferred over an active solution (equalisation).
[/LIST]

Regards

*A passive solution is always preferred along side use of an active solution if optimal sound quality is the objective.

Passive treatement in low frequencies will still leave signficant peaks in amplitude response; it can not eliminate them. Equalization must be used in conjunction with the passive treatment if optimal sound quality is desired.

Additionally, equalization can be used to compensate for high-frequency absorbtion differences of air in relation to your listening position distance(s).

-Chris

 

[Buckle-meister]

A passive solution is always preferred along side use of an active solution if optimal sound quality is the objective. Passive treatement in low frequencies will still leave signficant peaks in amplitude response; it can not eliminate them. Equalization must be used in conjunction with the passive treatment if optimal sound quality is desired.

Sorry WmAx. Perhaps I wasn't clear enough. I wasn't trying to say that equalisation wasn't to be pursued; you have stated before that both are required for an optimal room response and I understand this to be true. What I was trying to highlight was that since peaks are typically less in amplitude than nulls, targeting the latter via room treatment makes more sense if only room treatment or equalisation is to be employed. Wouldn't you agree?

...equalization can be used to compensate for high-frequency absorbtion differences of air in relation to your listening position distance(s).

Not that I'm saying there would be anything wrong in doing so, but wouldn't the above be adjustment for preference's sake, whereas room treatment actually helps solve inherent room problems?

Regards

 

[hankdog]

eq reply and revision

what I'm really tring to do is bring some of my peaks down in my subs, i was going to connect the eq inline with the subs, using the rives cd and radio shack spl meter i'm down-7 at 25 and +2 at 31.5 +2 at 50 and either =or - 1or 2 thru 63 80 100 125 and 160 , but if i reverse phase on the receiver i'm - 1 at 25 +8 at 31.5 +5 at 40 +7 at 50 +1at63 +8 at 80 +1 at 100 and +2 at 125 with all speakers set at small and crossover at 80 with the xo at 60 the peaks at 31.5 and 50 aren't as bad and 63 ,80 and 100, 125 are almost flat.

 

[WmAx]

What I was trying to highlight was that since peaks are typically less in amplitude than nulls, targeting the latter via room treatment makes more sense if only room treatment or equalisation is to be employed. Wouldn't you agree?

It is a judgement call. If sound quality for critical listening is the objective(as opposed to listening from multiple positions casually)I will suggest equalization as the first device to impliment, based upon:

-Perceptual research demonstrates that a peak is of a higher degree of detriment to sound quality as compared to a null of equal magnitude.

-To significantly alter low frequency room response with physical treatment requires a substantial amount of said treatment. The effect of room treatment upon low frequency characteristic will be small as compared to the effect that equalization can produce, relative to the amount of treatments allowable in a multi-purpose room.

-Chris

 

[WmAx]

I'm thinking of using an equalizer in my system, read the article about using rives audio cd and want to try an eq ,am looking at the art 351[in the article they used a 352 ]or might try a rane sse35, my system consists of a yamaha rxv2500 klipsch rf35 floorstand speakers rc35 center rs35 surrounds and 2 rw12 subs and the room is 14x20 with a 15 foot peak in the ceiling. It sounds very good but want to make it better any advise would be great. thanks.

I would recommend a *superior* equalizer for your purposes, that is also of lower cost than the ART product in which you are interested. Please refer to the Behringer DSP1124: http://www.zzounds.com/item--BEHDSP1124P

This product has the capability to specifically target room anomolies with far greater precision as compared to the the graphic equalizer that you previously referred to in your intitial post. If you are interested in future expansion/improvement of your system(with seperate pre-amp and amplifiers of which you can insert processing between the two) I will recommend the Behringer DCX2496, which is a combination crossover/equalizer system. It would allow superior integration of your main speakers and subwoofers as compared to the conventional options allowed in reciever crossovers/equalizers.

-Chris

 

[Buckle-meister]

...using the rives cd and radio shack spl meter i'm down -7 at 25 and +2 at 31.5 +2 at 50 and either = or - 1 or 2 thru 63 80 100 125 and 160...

Assumming the frequency response varied approximately linearly through the above points, I'd say you are doing extremely well and would be inclined to leave everything as is. Assumming the frequency response varied approximately linearly...

Regards

 

[hankdog]

rane sse35

I really appricate all the advise does anybody know any thing about the rane sse35 eq, i've researched it a bit and you can connect two subs to it and you can adjust the fronts and center separatly my wife said she will get it for me for christmas so how can i refuse.

 

[WmAx]

I really appricate all the advise does anybody know any thing about the rane sse35 eq, i've researched it a bit and you can connect two subs to it and you can adjust the fronts and center separatly my wife said she will get it for me for christmas so how can i refuse.

The RANE is a fine product. However, a DCX2496 is a far greater precision device and has more flexibility with one exception: The DCX2496 has a maximum of 3 input channels, where as the Rane SSE35 has 5 input channels. But the DCX2496 is on a whole other level of functionality as compared to the relatively primitive SSE35. It should be noted that multiple DCX2496 units can be daisy chained(one set as master, others to slaves) with ethernet cables in order to expand the number of input channels/output channels. If you can live with 3 input channels, it would certainly yeild significant benefits when you get to add a 2nd unit and have extensive DSP control of each channel. The DCX2496 will also provide you with powerful crossover abilities(far beyond capability found on SSE35) in order to enhance the performance of your system. If you need full functionality right now, and the cost of 2 DCX2496 is out of the price range that is acceptable($250 each x 2), then the Rane ($300) is the only viable option, unfortunately.

-Chris

 

[hankdog]

wmax

i looked at the dcx2496 how would i connect it to my receiver as it looks like it has xlr and 1/4" phone plugs can i use an 1/4" to rca adapter without any harm and really i might just use it to smooth the subs out a little thanks

 

[WmAx]

i looked at the dcx2496 how would i connect it to my receiver as it looks like it has xlr and 1/4" phone plugs can i use an 1/4" to rca adapter without any harm and really i might just use it to smooth the subs out a little thanks

The DCX has XLR jacks. You can use RCA-->XLR adapters, no problem. However, in some cases, the output signal from the DCX2496 might distort the input on the amplifier inputs(becuase the DCX, being a professional device, works at a higher line signal voltage). But the unit has up +/- 15dB gain settings on the outputs, so this will usually not be a problem. If it is a problem(your amp has very sensitive input, or you need greater degree of level adjustment for gain matching), it is easy to insert simple voltage divider(potentiometer) into the line with a custom cable.

-Chris

 

[Ethan Winer]

Chris,

You and Robbie are doing a great job discussing the pros and cons of EQ and bass traps, so for now I'll add just a little.

> Passive treatement in low frequencies will still leave signficant peaks in amplitude response; it can not eliminate them. <

Correct - neither passive treatment (bass traps) nor EQ can truly flatten a room's response. But don't be so quick to think that bass traps can't have an enormous affect at low frequencies. At least not, good bass traps. I regularly see a substantial improvement as low as 40 Hz, and helping even lower is possible. See the review right here that Robbie just published:

http://forums.audioholics.com/forums/showthread.php?p=123984#post123984

If you look at the waterfall plots you'll see a noticeable improvement all the way down to the lowest peak, which looks to be around 35 Hz. The peak level is lowered and the ringing time is also reduced.

Yes, a fair number of traps is needed, but on a cost to benefit ratio of 1) upgrading loudspeakers or buying other "gear" versus 2) spending the same amount on bass traps, I'd say bass traps easily give the larger benefit.

> Perceptual research demonstrates that a peak is of a higher degree of detriment to sound quality as compared to a null of equal magnitude. <

That really isn't true, at least not in the context of bass traps and listening to music in a real-life room. A deep null is arguably far more damaging than a peak, at least when the null aligns with the fundamental or 2nd harmonic of a bass note. This depends on the room and the key of the music, of course. A bass null is typically 20 or more dB deep - 35 dB deep is common - and I promise you this is very audible when the null and music are at the same frequency.

> The effect of room treatment upon low frequency characteristic will be small as compared to the effect that equalization can produce <

I'll argue exactly the opposite. EQ can help to flatten the raw response, but it does nothing for ringing which is at least as damaging as the skewed response (ringing creates the "one note bass" effect). EQ also adds ringing, as shown in a recent "shootout" I took part in for the AVS forum. We compared exactly what is being discussed here: the efficacy of EQ versus bass traps. For the EQ part of the tests a pro acoustician made the adjustments, and the result was perhaps flatter than without EQ, but the EQ added substantial low frequency ringing to the system.

--Ethan

 

[ironlung]

I'll argue exactly the opposite. EQ can help to flatten the raw response, but it does nothing for ringing which is at least as damaging as the skewed response (ringing creates the "one note bass" effect). EQ also adds ringing, as shown in a recent "shootout" I took part in for the AVS forum. We compared exactly what is being discussed here: the efficacy of EQ versus bass traps. For the EQ part of the tests a pro acoustician made the adjustments, and the result was perhaps flatter than without EQ, but the EQ added substantial low frequency ringing to the system.

--Ethan

Ethan,

With this statement. Do you NOT recommend electronic manipulation of room response at all? Is it OK to use room treatment to get the best response possible that space/budget/decor allow and use a PEQ to do the final tweak?

Thanks

 

[WmAx]

Chris,


Yes, a fair number of traps is needed, but on a cost to benefit ratio of 1) upgrading loudspeakers or buying other "gear" versus 2) spending the same amount on bass traps, I'd say bass traps easily give the larger benefit.

Part of the discussion here is largely revolving around practical applications for general user(s), and the cost to benefit ratio, as you rightfully point out. But a low noise equalizer can be had for $100 that is suitable to equalize the response, and with nothing more than inserting into the signal line and setting up the parametric parameters. Bass traps, on the other hand, such as purchased from a manufacturer or retailer, will end up being costlier and more difficult to integrate. I can not agree that bass traps are of a higher cost to benefit ratio concerning the actual cost and physical set up requirements. Of course, both are needed to be used in conjunction with each other for the best response characteristic(s).

WmAx: Perceptual research demonstrates that a peak is of a higher degree of detriment to sound quality as compared to a null of equal magnitude. <

Ethan Winer: That really isn't true, at least not in the context of bass traps and listening to music in a real-life room. A deep null is arguably far more damaging than a peak, at least when the null aligns with the fundamental or 2nd harmonic of a bass note. This depends on the room and the key of the music, of course. A bass null is typically 20 or more dB deep - 35 dB deep is common - and I promise you this is very audible when the null and music are at the same frequency.

How is this not true in the contexty of low frequencies? The fundamental/harmonic has the same rate of incidence with the peak as compared to a null of equal center frequency, bandwidth and magnitude. Established perceptual [1]research has concluded that an anomoly of equal magnitude, a null is less objectionable than a peak.

I'll argue exactly the opposite. EQ can help to flatten the raw response, but it does nothing for ringing which is at least as damaging as the skewed response

Both factors[time delayed repetition and ampliltude response] are damaging to the sound quality. The equalizer can substantially correct amplitude related issues. As you already know(but I will add for the purposes of readers here) an equalizer does not actually 'add' ringing, it's the modification of frequency response itself that causes the ringing. While the room response peaks can be removed, the equalizer in reality has caused a discontinuity in the raw frequency response from the speaker(assuming it had a linear anechoic response). This non-linear shift in amplitude at a high rate of change in the source signal dispersing from the loudspeaker causes a severe phase shift, resulting in energy storage/release that is not time correlated with the original signal. But the modification in this manner may substantially improve the sound quality of the room by removing the overall huge amplitude variation that was occuring at low frequencies when left uncorrected. An equalizer, when dealing with non-delayed resonances, can actually be used to remove ringing. For example: if the speaker's anechoic response is not linear(resonance), correcting this via an equalizer will reduce ringing.

(ringing creates the "one note bass" effect). EQ also adds ringing, as shown in a recent "shootout" I took part in for the AVS forum.

Non delayed resonance will also causes "one note bass".

We compared exactly what is being discussed here: the efficacy of EQ versus bass traps. For the EQ part of the tests a pro acoustician made the adjustments, and the result was perhaps flatter than without EQ, but the EQ added substantial low frequency ringing to the system.

I would like to read the article, can you please provide the link?

Needless to say, but the added ringing must be correlated to perceptual research in order to determine the magnitude of audible detriment relative to measurement(s).

-Chris

[1]The Audibility of Frequency Response Irregularities
R. Bucklein
JAES, Vol. 29, 1981, pages 126-131

 

[Buckle-meister]

Is it OK to use room treatment to get the best response possible that space/budget/decor allow and use a PEQ to do the final tweak?

I won't attempt to answer for Ethan, but the above quote is exactly how I feel a room should be tackled; au natural. I also feel (perhaps from my own ignorance) that too many people rush to buy a PEQ without knowing exactly how to use it. It's easy for WmAx to advise a particular PEQ, but then, he fully understands how to use one.

With a PEQ, if you don't fully know how to use it, then there must surely be a greater capacity to do harm to the room's response than good. At least with room treatment that's almost impossible, since absorption will vary only by degree.

Regards

 

[WmAx]

I won't attempt to answer for Ethan, but the above quote is exactly how I feel a room should be tackled; au natural. I also feel (perhaps from my own ignorance) that too many people rush to buy a PEQ without knowing exactly how to use it. It's easy for WmAx to advise a particular PEQ, but then, he fully understands how to use one.

With a PEQ, if you don't fully know how to use it, then there must surely be a greater capacity to do harm to the room's response than good. At least with room treatment that's almost impossible, since absorption will vary only by degree.

Regards

If you want optimal response, you must use both, unless your room is the equivalent of a giant basstrap itself. As you can see from your own measurements, bass traps have little effect at low frequencies under 50Hz. These problems are easily corrected to a large degree with additional PEQ tweaking. I use both equalization and physical room treatments; I would not want to be without either one.

-Chris

 

[Buckle-meister]

If you want optimal response, you must use both... I use both equalization and physical room treatments; I would not want to be without either one.

WmAx; I'm not saying that equalisation shouldn't be used. I intend on using it somewhere along the way myself, but I think sometimes you tend to forget that the overwhelming majority of folk do not possess the depth or breadth of technical knowledge that you do.

An ignorant but enthusiastic person like myself can make substantial inroads with treatment. I wouldn't be nearly so confident about saying the same with regard to equalisation.

Regards

 

[WmAx]

An ignorant but enthusiastic person like myself can make substantial inroads with treatment. I wouldn't be nearly so confident about saying the same with regard to equalisation.

Regards

Excellent point.

-Chris

 

[Buckle-meister]

As you can see from your own measurements, bass traps have little effect at low frequencies under 50Hz. These problems are easily corrected to a large degree with additional PEQ tweaking.

How? I thought raising nulls with a PEQ was 'asking for it' given that the amp would be significantly more taxed, and that the artificially induced additional driver excursion of the speakers could, if not very careful...

D e s t r o y T h e m!

Regards