Equalizer or subwoofer?

[jaudere]

Thanks trittya. managed it with your guidance. Now about the experiment.

1) If one looks as the curve, even though the claimed range is 50Hz to 18kHZ, actually that 50Hz is at 75dB or so.
The response starts dropping bellow 200Hz and drastically so below 90Hz. From 200Hz to 5kHZ, it is around 100dB with a dip from 600-800 (it is aropund 95dB).
From 6khz to 9KHZ, there is a peak to almost 105dB. From10kHz onwards, it is not really usable response.

2) My bands are 63Hz, 125Hz, 250Hz, 500Hz, 1KHz, 2khz, 4khz, 8khz, 16khz. they will be of constant Q but I do not know the Q value.
My amplifier gives a boost of +8dB at 50Hz when loudness switch is on. It it is left on.
Going by the graph (which is probably generated in anechoic chamber (Ahuja really has anechoic chamber in their R&D as per their website!), and with a goal to reach 90db average, I have to set
63Hz at +10db, 125 0db, 250 at-10, 500hz at -10, 1kHz at -10, 2khz at -10, 4khz at -6, 8khz at-12 and leave 16Khz untouched.

3) If I set equalizers as per this, the sound is BAD! So obvisouly my room is playing games. So rather than having such wide differences between various bands, it reduced each value (boost/cut at each band) by half of the planned and that does the trick.

So the graph has given a rough guideline about relative positions of various sliders but in my room the response of the driver is not as fluctuating as that in the picture above and so I need lesser adjustments.

Experts please opine if my logic is correct!

@ Trittya: This was the only one equalizer with RCA in and out. All others have balanced connectios only. So Even if I want to upgrade, I don't know how to go about it. unbalanced TRS to RCA is easy to get but Balanced TRS jack to RCA is difficult to get and I am in no position to DIY the cables.

 

[trittya]

My bands are 63Hz, 125Hz, 250Hz, 500Hz, 1KHz, 2khz, 4khz, 8khz, 16khz. they will be of constant Q but I do not know the Q value.
My amplifier gives a boost of +8dB at 50Hz when loudness switch is on. It it is left on.

Though I am no expert, methinx one can cater to the Q factor with a parametric equalizer.
Here is some wiki gyaan on the term:
QUOTE
Parametric equalizers are multi-band variable equalizers which allow users to control the three primary parameters: amplitude, center frequency and bandwidth. The amplitude of each band can be controlled, and the center frequency can be shifted, and bandwidth ("Q") can be widened or narrowed. Parametric equalizers are capable of making much more precise adjustments to sound than other equalizers, and are commonly used in sound recording and live sound reinforcement. Parametric equalizers are also sold as standalone outboard gear units.

A variant of the parametric equalizer is the semi-parametric equalizer, also known as a sweepable filter. It allows users to control the amplitude and frequency, but uses a pre-set bandwidth of the center frequency. In some cases, semi-parametric equalizers allow the user to select between a wide and a narrow preset bandwidth.
UNQUOTE

I have a guest, will post more ASAP
Regards

 

[jaudere]

I read about parametric EQs also but am going with graphic for the sake of simplicity.
Setting the Q value (bandwidth is bit too complicated. Parametric equalizers are there in foobar also. i tried to use them but was confused.

 

[t.antony]

The main difference between a 31 band and 9 band eq is that the former will almost alleviate the need for a parametric eq to shape the response curve more precisely. More bands in your eq always help in bringing forth more control on your speakers and more details in reproduced music (according to your taste). The Behringer Ultracurve is an expensive and useful equipment and costs a bit high for the overall build quality. The cost is a deterrent for me as well and I am currently experimenting with VST plugins for my (much delayed) Open Baffle project.

IMO your earlier choice(NX EQ1215) or the 31 band DBX model you were mentioning could have been better than your current Behringer. However, since the results are good, may be further upgrades can wait a bit longer ...

And you are right about the fact that using equalizer works out cheaper and often easier than doing acoustic treatments. A 9 band eq is working well for you probably because your speakers are open baffle and OB's are less susceptible to room interaction. It also throws some light into the fact that you could boost and cut the bands w.r.t the frequency response of the speaker in an anechoic chamber.

Equalizers need to be more flexible(more bands/parametric capabilities) to be effective in the case of ported or sealed enclosures.

 

[jaudere]

There was some issue with the unit. It did not have input gain control (which I realized later) and accepts only upto 15 dBU signals. The CD output is 2V Rms (i don't know how many dBU it means) but when input signal was monitored, the clip LED was intermittently lighting.

So I have decided to go for DBX which accepts upto 21dBU signals and has input gain control.
I am getting full refund for Behringer unit. Buying DBx from same person.

Please have a look at following and let me know your opinion.
215 is 15 band EQ (costing 10.5k) and 231 is 31 band(costing 14.8k).
Now that I have full faith in EQ capabilities, I won't mind spending15k.

231 Dual Channel 31-Band Equalizer :: dbx Professional Products

215s Dual Channel 15-Band Equalizer :: dbx Professional Products

What should I choose? I am inclining towards 31 band.

 

[theredcommando]

Why not you try something like Goldwave GoldWave - Audio Editor, Recorder, Converter, Restoration, & Analysis Software and generate different signals for various frequency boost with known songs, apply parametric eq etc. Playing some test signals with log 2 difference(10-20-40-80 Hz) might also give idea about room response.
If you get a good microphone, you might be able to analyze the recorded sound as well(for eg in Goldwave).
When processing can be done at digital level, I think that should be preferred route instead of analogue one(like hardware eq). If hardware eq has some DSP then again SQ would be lesser as there is interconversion.

Any cheap laptop could be bought and you can use hibernate/sleep so that you could resume with 10 sec delay. Advantages it would provide are multiple IMO.

You can try them out and then decide further.

 

[t.antony]

dbx 31 band model is a good choice - 231 Dual Channel 31-Band Equalizer :: dbx Professional Products

 

[trittya]

Please have a look at following and let me know your opinion.
215 is 15 band EQ (costing 10.5k) and 231 is 31 band(costing 14.8k).
Now that I have full faith in EQ capabilities, I won't mind spending15k.

231 Dual Channel 31-Band Equalizer :: dbx Professional Products

215s Dual Channel 15-Band Equalizer :: dbx Professional Products

What should I choose? I am inclining towards 31 band.

As per the website
"The 231 has been discontinued. Please see the 231s."
231s Dual Channel 31-Band Equalizer :: dbx Professional Products

QOTOH, you may get the 231 a mite cheaper because of this. Just make sure you check the tech differences between the two and ascertain that the reason for discontinuation doesnt affect you. If you think it does, go for the 231s.

See if you can get some expert FM to comment on the difference between these two
http://www.dbxpro.com/231/specs.php
http://www.dbxpro.com/231s/specs.php

There appears to be a difference in the type of non-XLR connector sockets on the rear panel, it may be the same size though.

The 231

The 231s

The front appears to be essentially the same, but it looks better in black

The 231

The 231s

Cheerio

 

[jaudere]

Hi,
Thanks for the images. Even I was trying to find out what is exactly different in 231S but couldn't. At least in the backside, there is power switch in 231 and it is not there in 231s(strange). The non XLR connectors, even though look externally different, they both accept TRS jacks.

Even I liked the black colour much more. I have ordered one. Now I am looking for real time spectrum analyzer so that i can find out respones of various frequencies in my room and set equalizers accordingly. someone has suggested use of smartphone for this. Do you guys have any experience in this.
there are softwares available for this.

https://play.google.com/store/apps/details?id=com.electronchaos.SpeedySpectrumAnalyzer&hl=en

Audio realtime analyzer nokia app trend: Realtime Analyzer RAL, Realtime Analyzer RAE, Realtime Analyzer RAD

 

[jaudere]

Hi,
I finally got by dbx 231 today. 231s was available only in silver colour . So I opted for 231 , black. Cost: Rs14500. 1 year warranty.

Difference between 231 and 231S is better dynamic range (108 vs112), better SNR (>90 vs >95). 231 has a separate power switch, 231S does not.

I do not think these specifications will make any difference in real life home audio.

Now it is time to form different settings. . Preliminary results are encouraging.

I am trying some cheap room treatment as well. The idea being no 2 parallel walls should have free wall. So out of 6 surface es in room, one wall is covered with bookshelf of full height, the surface behind listening position is covered with a 6' X 3' mattress of 3 inch thickness. I will be putting thick, soft mattress on floor as well. No treatment for remaining 3 walls. I have not changed curtains of the big windows. I just ensure that the curtains are drawn when playing music.
The difficult part is I cannot do do A-B comparison with mattresses on and off or bookshelf on and off. I just hope that it at least makes some good suble changes. Not spending a rupee on room treatment at present. Just trying it out with whatever available at home.

 

[trittya]

Way to go, Doc
:clapping::clapping:
Do tell us how it fares . . .

 

[Sumanta]

Same from me too Jaudere. Carry on your journey, pleasure where lies.

 

[jaudere]

I am happy with the 31 band dbx over the 9 band Behringer.
The main reason is that the lowest band on Behringer was 63Hz. Nothing controllable below that + precise control over midrange.
There was no audible distortion with either of the EQs. The behringer was reaching clipping limit many times with the input signal but that issue is solved with dBX. The signal remains within safe range even when input gain is kept at zero. Looks wise dbx scores much higher.

(By the way,I showed this new piece of equipment to the kids and I asked them what it is. They said follwing : Amplifier, CD player, mixer. I am happy to know they thought of some audio equipment even though answers were wrong.My son is 3 year old and daughetr is 5 year old. )


If I try to completely get a flat curve by adjusting EQ depending on the Frequency response curve, it gets overdone and results in poor sound quality. Rather than than I have kept the curve of bands similar but I have not kept the boost/cut level in ranges of +/- 10db. Except in lower freq (upto 63, it is cut by 2-3 db, nothing more than that). This adjustment is done going by ear after taking basic help from the frequency response curve.

I have boosted 40Hz, 50Hz and 63 HZ by 6dB, 80 Hz b 3db, 100, 125 at 0,
rest of it is a cut by -2 to -3db from 160 Hz to 8kHz with no boost/cut above 10kHz. It is said that cutting is better than boosting but I had to boost lower frequencies because my speaker seem to be weak there.

The speakers had a midrange shout (may be that's why Sumanta called it to give a tube like sound), which I realized few weeks back. That is gone now. Lower frequencies are vastly improved. HF are as good as they were.

The following songs had bass notes touching the heart,I was missing them.

1) Yeh jo des hai tera: Swades: the song start with a thump. that was completely missing before. Now I can feel it.

2) Tu bin bataye: Rang de basanti: This song also has a thump in intial part wher the lady singer is signing without too many instruments. I was missing that.

3) Play me: Neil Diamond: what a bass guitar! I could hear it previously but it was lost in background. I knew it was there only because I have played bass guitar in past. Now it nicely complements the song.

4) Taal se taal mila : Taal: After the initial tarana of Sukhwinder sing, the rhythm starts with deep thumps. I was missing that.

5) I have started loving Gary Moore blues after using equalizers. Before that, it was not touching me.

There is no sign of boominess at all. Nice , deep, musical bass.

Overall, a significant improvement in lower and mid frequencies without compromising highs. With a sunwoofer, I was not getting the balance well and teh sub was doing nothing for the midrange shout.

Many purist may not like the idea of lengthening and altering the signal path. However, after reading many articles , it seems that recording engineers almost universally use some kind of equalizers, sometimes on each channel separately and again on the final mix. So I decided to give it a try and I am happy with the result.

 

[debzkool]

Hey Jaudere,
I am also in the lookout for a good/budget equalizer. Do let me know where did you buy the 231s DBX from.

Thanks Deb