Make sense of EQ Wizard results

[skiroy]

This is at listening position -20db 20hz-18k sine sweep.But I have no idea what it means or how to correct it if there is something wrong.What is the normal ranges for this graph.My input signal I sent around -24db.
How do I tell if my problem is bass trap related,reflection related or speaker placement/spacing issue?

[skiroy]

[Ethan Winer]

Originally Posted by skiroy

How do I tell if my problem is bass trap related,reflection related or speaker placement/spacing issue?

You move the speakers and measuring microphone etc and see what changes.

--Ethan

[skiroy]

Okay I will try that.But can you please help me interpret the graph?Whats normal and abnormal here?Where are my issues as far as what frequencies and what issues do they coresspond to?
For example,20hz -xHz means need more bass trapping.And everything above xHZ means a speaker placement issue and the area around xKHZ is related to the need of broadband reflection panels.

[skiroy]

Is it same to assume that between 48-65db is the safe zone and that I should ignore the graph from 20Hz-40Hz?

[skiroy]

bump.Last question for a while guys promise.I go thru sperts of relentless scattered research but I think I got it out of my system after I figure this one out.Thankx for being patient.

[Ethan Winer]

Originally Posted by skiroy

For example,20hz -xHz means need more bass trapping.And everything above xHZ means a speaker placement issue and the area around xKHZ is related to the need of broadband reflection panels.

Problems below 300 Hz are related to the room and to speaker placement. Problems above that are mostly due to untamed reflections around the listening position. Do you have any treatment now?

Is it same to assume that between 48-65db is the safe zone and that I should ignore the graph from 20Hz-40Hz?

You should not ignore anything within the range your speakers can reproduce.

Without knowing what treatment you have now, or the size of this room, I can't even guess. But I can tell you that all rooms need as many bass traps as possible, plus absorption at the side-wall and ceiling reflection points. Do that and you'll be 90 percent of the way there.

--Ethan

[skiroy]

I have only foam ocrner traps but plan on building 8 for my 20ft x 20ft room.So I know that is a problem.I do have a refelction 703 panels behind my speakers on the sides of the walls and the roof. Looking at the graph above could you tell me if I have reflection problems and or bass trouble?
Thats the problem,I do not know how to interpret if and where my problems occur.Is this graph normal?

[Ethan Winer]

Originally Posted by skiroy

I do have a refelction 703 panels behind my speakers on the sides of the walls and the roof.

Panels behind your speakers don't do much, but if you have the sides and ceilings treated, you should be okay.

Looking at the graph above could you tell me if I have reflection problems and or bass trouble?

Bass trouble.

Thats the problem,I do not know how to interpret if and where my problems occur.Is this graph normal?

Yes, the graph is normal.

My goal usually is to simplify these things for people, but the causes of individual peaks and nulls are not always simple. If you play a sweep tone from two speakers in an anechoic chamber (100 percent absorption), you can still get peaks and nulls if the microphone is half an inch closer to one speaker than to another. So I usually ignore problems at mid and high frequencies as long as all the reflection points are treated.

--Ethan

[skiroy]

So Im looking from 20-300hz range,okay.Where specifically in my 20-300hz range on the graph is my problem frquencies and what am I shooting for?So when I add my bass traping and redo the test what am I looking to be different on my graph, because the 20-300hz doesnt look that out of wack to me in comparison to the rest out the graph that actually looks more extreme to me?

[Ethan Winer]

Originally Posted by skiroy

Where specifically in my 20-300hz range on the graph is my problem frquencies and what am I shooting for?So when I add my bass traping and redo the test what am I looking to be different on my graph

See my Density Report for a good example of how a room changes when bass traps are added.

--Ethan

[skiroy]

Wow Im starting to think that this is way over my head by reading your article.I hope I did waste 450.00 on a test mic I cant use.My best gues from this graph is that my 20-40hz is too low aswell as my 100hz.And Im to high at 150hz.Am I even close?

[Ethan Winer]

Dude, forget the graphs and just add a bunch of bass traps already.

Seriously, no matter what is measured, adding bass traps is always the solution.

Also, what microphone did you get? Surely it's useful for recording too?

--Ethan

[skiroy]

Behringer Ecm8000.

[Ethan Winer]

$450?

[imloggedin]

LOL i hope you meant 45$

[DanDan]

Room Analysis Primer
That article should give you a quick fix as to how but perhaps more importantly not to bother. It has a sub text identical to Ethan's point, i.e. why measure if it only generates questions? The Treatment prescription will not change significantly no matter what curves appear.
It is not easy to interpret results from these measurements. In many cases you need to know the answer by other means and then use the measurement to confirm it . More usefully measurement can show changes really well.

Forget about the measurements. Read the Treatment info at Studiotips GIK and RealTraps or elsewhere. Install or move your Traps according to the simple guidelines and you are done. I say, you will never have enough but your efforts will be well rewarded.

You are in bad company, REW is flaky and it's sources questionable.
Behringer are being sued for breach of patent, constantly, plus they manufacture their stuff in Hell.

I think there is a UN scheme where they will send out a team to your Studio to safely remove anything Behringer.
Meanwhile be safe.....
DD

[Ethan Winer]

Originally Posted by DanDan

REW is flaky and it's sources questionable.

Just to clarify, REW works very well on PCs, but I hear there are problems running it on a Mac.

--Ethan

[DanDan]

Hi Ethan, I used the word flaky in a very broad sense, I meant to be simply discouraging in terms of REW.
REW may seen to be 'free' but access to it is restricted to one advertisement- laden source. Perhaps REW is paid for or sponsored in some way by that source. I am open to correction on that assumption.
I think such a 'free' offering distorts normal competition and threatens survival of more transparently sourced, honest, products. There are at least two serious products out there for very reasonable money-FuzzMeasure and ETF. I always encourage support for these. I believe that is only fair. If these two fail due to a 'free' alternative, where does that leave us?
If REW were to separate from it's only port of access, and become entirely free, paid, or even better, shareware, I would take it seriously. Until then I cannot encourage it's use.
Furthermore a large part of REW is taken up with a corrective Eq solution to room problems, a last resort for most of us, reeking of Snake Oil.
To add insult to injury REW generates curves specifically for a Behringer product. Behringer are constantly in breach of patent. They steal designs and get them made in Hell.
As I say, I used the word 'flaky' in a very broad sense :-)
DD

[Ethan Winer]

Originally Posted by DanDan

access to it is restricted to one advertisement- laden source.

Yes, and that source is also a lame place to get advice on anything other than REW.

Furthermore a large part of REW is taken up with a corrective Eq solution to room problems, a last resort for most of us, reeking of Snake Oil.

Agreed.

--Ethan

[skiroy]

Ethan, I have done lots of treatment in my room and I have just reshot my room with REW. Could you look at this measurement file. Im hope you have REW. I did 2 measurements on both my Event ASP 8s and NS 10s.
I am uploading the file that includes all the measurements for both.

I did 4 measurements for each set od speakers and save all 4 as a file
I did from

1. 10-250hz
2.250hz- 2k
3. 2K-6K
4. 6k-12k
Just so its easier to see on the waterfall views.

On both speakers,but more so on the ASP 8s it appears there is a null around 70hz. There seems to be a increase around 130 on asp8s and a peak around 200is for NS10s

My problem is I dont know how much a frequency range has to be higher or lower than the reference point to be considered a problematic null or peak.

My other issue is choosing a reference point.

Could you look at the grapgh and give my some clues as to what would be a good DB value to choose as my average reference point and what ranges you would consider an unacceptable null and/or peak?

besides the obvious null at 70hz is everythin in the high end acceptable?

Thankx,

[skiroy]

Im now shoot my small vocal area. Im going to use the NS 10s because I think they are a flatter choice then MY asp8s
Now my vox area is small only a 2 wall corner with gobos that forms a 3rd zig zag wall. SO my entire area is about 6ft x 5ft x 7ft high(because I have hung 4" owns panels on ceiling. I also have a 4" owens trap in the corner of the booth which I face when doing vocals. Now this area is just for vocals and maybe some percussion parts like shakers,claves ect.
I am assuming I want this area to be on the flat side.

So could you tell me if this is an appropriate reading method?

I have the mic in the same area facing the same way as if I were to be doing vocals. I then have an NS-10 head height about 3ft away from the mic.
Is this okay?

And how should I break up the test? 10-3K and then 3K-12K?

[Ethan Winer]

Originally Posted by skiroy

I did 4 measurements for each set od speakers and save all 4 as a file ... Just so its easier to see on the waterfall views.

It's easier to measure the full range once, then change the display settings to view different ranges.

My problem is I dont know how much a frequency range has to be higher or lower than the reference point to be considered a problematic null or peak.

If you can get the response to within a 10 dB window you're doing very well.

My other issue is choosing a reference point.

Acoustics is linear, so the "zero" level is irrelevant. All that matters is that you play the sweeps loud enough to be well above the room's ambient noise level. Otherwise the true extent of nulls is hidden.

besides the obvious null at 70hz is everythin in the high end acceptable?

Well, your 200 Hz to 2 KHz has 1 octave averaging, so that doesn't tell you anything useful. Again, it's best to measure the full range, then you can see all ranges in the proper relation to each other.

--Ethan

[skiroy]

Originally Posted by Ethan Winer

It's easier to measure the full range once, then change the display settings to view different ranges.



If you can get the response to within a 10 dB window you're doing very well.



Acoustics is linear, so the "zero" level is irrelevant. All that matters is that you play the sweeps loud enough to be well above the room's ambient noise level. Otherwise the true extent of nulls is hidden.



Well, your 200 Hz to 2 KHz has 1 octave averaging, so that doesn't tell you anything useful. Again, it's best to measure the full range, then you can see all ranges in the proper relation to each other.

--Ethan

Okay I will reshoot it tommorrow. But what I dont understand is why it records the signal at -18db but then on the chart it reads between 60-90db?
Would you say Im reading loud enough? Im pretty much crankin it to get the reading just before clipping.

[Ethan Winer]

Originally Posted by skiroy

what I dont understand is why it records the signal at -18db but then on the chart it reads between 60-90db?

The -18 is the signal level from your preamp, and the 60-90 is the SPL level in the room. So apples and oranges.

Would you say Im reading loud enough? Im pretty much crankin it to get the reading just before clipping.

You should set the playback volume to be "fairly loud" in the room, maybe 85 dB SPL. Then adjust the mic preamp for a decent level, maybe between -10 and -5 on the record level meter.

--Ethan