ot Need Advice About Room EQ

[DHG MUSIC]

Hello Friends

I have an expert come to my place and try to eq my Adams speakers ( s3a and s5a )


we were able to have a quasi flat response on the full spectrum with the exception of a big ass hole in 73 hz and a Massive bump in 146 hz


Any way, this is my question

Im looking into buying some sort of digital eq for the speakers to try to apply some corrective eq to the situation

I realize I should rebuild, reform, or alter the room, but believe me, budget and time, are not something I have to invest anymore


Could you guys please recomend/ comment?


Im looking into the Ashly 424gs


Thanks in advance

[Drew Mazurek]

IMO, good speakers should NOT be EQed. Treat the room!!! It doesn't have to cost a fortune if you're willing to do the research and DIY.


Besides, the EQ will only make it sound "right" in ONE PLACE, where the mic was. A treated room will sound "right" everywhere in the room.

[DHG MUSIC]

I dont mean to sound ungreatful to you, for taking the time to respond and educate me, neither I wish to be confrontational, but I have a question

If good speakers should not be eqd why the adams have an eq in the front?

Again not beeing disrecpecful, just trying to educate myself


Thanks for your time

[Drew Mazurek]

Right, use the EQ on the Adams to tailor it to a properly treated room and to account for placement. For example, placing them against a wall causes them to "couple" with the wall and the Roll Off on the speaker is there to accommodate for that. But IMO don't buy an Ashley digital eq and try to fix a room with an eq. I bet if you emailed Adam and asked them if it was appropriate to eq their monitors they'd tell you the same thing.

[Stig Eliassen]

It's the same thing with Genelec 1030A's. The bass roll-off/tilt options are there to correct speaker placement when space is limited.

[DrFord]

Well every single professional studio I have ever worked in or had the pleasure to visit has been both acoustically treated AND hardware EQ'd before the amps. Usually, this is reserved more for the mains, as I don't see this much for nearfields. Most professional engineers I work with bring their own set of nearfields, or end up swapping between several pairs during final mixdown. Thus there is no point EQing the Nearfield monitors that will be moved, changed, or jabbed with a pencil.

On your specific issue....

Having a bump at 146 means a buildup of waves. Having a hole at 73 hz is waves phase canceling each other. These are obviously the same waves, just a higher octave of the fundamental. Bass travels omni-directional, unlike mids and highs which travel like light. Mids and highs bounce off surfaces and reflect. Acoustical tiles, diffusion panels, egg cartons... these are all devices to spread reflection of mids and highs so that they don't bounce back at the mix position and smear themselves, or bounce back into a microphone, or to eliminate "room tone" making the space more "dead" and less like a "live room."

These options are not going to help you for your specific problem, however they will help tune the room to your liking. The best bet would be to place a diffuser of some sort directly behind your mix position, and usually to the sides. Then, anywhere you can see the speakers in a mirror - with a mirror held against all walls... looking from eye / ear level in the mix chair... (ceiling included) should have a non reflective / acoustical tile surface to stop sound from reflecting back to the mix ears. This will greatly affect your 1st reflections of sound and make your mix more precise, as you will be hearing only what comes out of the speakers. When you turn your head you hear very different things and each speaker should become dominant. If you were to use only diffusers, you would make the space feel more like being outdoors in a field. If you choose to only use absorption panels like Acoustical tiles made with Owens Corning 70X series, you will be dampening your room and making it sound more like a vacuum. This is a very 1970's concept, rooms so dead that you hear the music stands vibrating when you sing.

The Answer

To solve your 73 / 146 problem you are going to need a few things.

Hz Chart info
D 73.4 D-string on bass
D 146.8 D-string on guitar

Room Mode / Standing Waves Calculator
http://www.marktaw.com/recording/Aco...WaveCalcu.html

Audio Wavelength Calculator
http://www.mcsquared.com/wavelength.htm

Gathered Info

73.4 hz = 15.39509536784741 feet - full 360 degree wavelength.

3/4 wavelength = 11.546321525885558 feet

1/2 wavelengths = 7.697547683923705 feet

1/4 wavelengths = 3.848773841961853 Feet

146.8 hz = 7.697547683923705 feet full wavelength.

1/2 Wavelengths = 3.848773841961853 Feet


Conclusion

As you will notice both frequencies share an exact pure tone sine wave compression point. The 73.4 hz frequency at 1/4 wavelength is the same as the 146.8 hz wave at 1/2 wavelength. So if you Build a Bass trap set to trap the frequency at 3.85 feet approx.... you will solve your problem, or at least measurably improve it.

To build a proper bass trap, you need to follow exact specifications or hire a studio contractor to build it for you. Many studio owners have found very creative ways to hide bass traps in their control room. Many will create a riser and set the client couch on it in the rear of the room. I have seen some make a false wall at the back of the studio, and I have also seen some make 45 degree corner inserts (usually the easiest to construct DIY) ... symmetrical triangle where the height of the common point is the length of the wave you want to capture... 3.85 ft approx.

Follow guidelines found on this forum... the ultimate resource for studio design and construction.

http://www.johnlsayers.com/phpBB2/index.php

Helmholtz Resonator Design - You tailor it to the frequency we figured

http://www.johnlsayers.com/phpBB2/vi...hp?f=3&t=14270

Helmholtz Calc

http://www.johnlsayers.com/phpBB2/vi...php?f=3&t=1351



A Helmholtz Resonator can be more efficient than a more simple Bass trap, however they are more difficult to build. There are many great videos and articles online which will walk you through building a proper basstrap. Just remember that most basstraps are generic. You need to be specific, and the best way to do this is to build the trap to trap the specific frequencies you need. When the box is the right size, the trap will grab the one wave that fits inside it. Inside your airtight trap box, you will have packed it with fiberglass, which will over time slow the wavespeed and absorb it.

Just remember that Bass Frequencies are heat energy transfers, and can move through walls. This is why outside the nightclub you only hear the kick drum. Mechanically connected subwoofers or really any speaker will transfer vibration to any other desk / floor / ceiling that is mechanically connected. I have seen many engineers place Owens Corning pieces under their speakers to "decouple" the speakers from the floor, which transfers less vibrations / hear energy and this does not transmit bass as much.

I hope this helps.

Best,
Doc

[DrFord]

Additionally, Once you have treated your room and you have found that the acoustic construction fixes you have built only partially fix the problem... THEN you hardware EQ before your amps / speakers.

The reason is that once you have treated the room, the treatment will both positively and negatively affect your room sound. The EQ is to fine tune the construction, not a substitute for.

Doc

[wolfman_rob]

fixing the problems with the room is the best place to start but

I had the same problem had a less than great room a busy scedule and no time to deal with the problem room in the correct way.


TDM Version

http://pro-audio.musiciansfriend.com...cel?sku=502737


RTAS Version

http://pro-audio.musiciansfriend.com...tem?sku=703090


I Know People with argue with this being effective but it does work !!!!

This may not have solved my problem 100% but it did help alot and gave me a little time to get my mixes closer to what i wanted that translated better on other systems . and as i have time i do what remodeling and revamping my mixing room as i can scedule time off to do so.

kind of expensive but you wont get this result with a regular EQ i dont think

also i think there are a couple of other systems out there that are similar maybe one made by KRK or something

hope this helps a little


Russell

[Craig F]

or get the hardware version http://www.audyssey.com/products?f=proaudio
cheap EQ (Ashly, dbx, ect.) adds to much noise

[garnoil]

Originally Posted by DHG MUSIC

Hello Friends

I have an expert come to my place and try to eq my Adams speakers ( s3a and s5a )


we were able to have a quasi flat response on the full spectrum with the exception of a big ass hole in 73 hz and a Massive bump in 146 hz

Thanks in advance

How big is your room? and how wide or narrow is the 73hz dip? also, how did your expert measure the response, where are your speaker located (how far from a wall, corner, flat on a desk etc...)