Need help with spectrum analyzer

[Paul S.]

Can anyone tell me if this a good reading? I took it using white noise. New to this so im willing to learn. 

[Holmz]

It looks more like pink noise than white, but that might be the room boosting the lows. But there is still a 20dB slope from ~2kHz to 20kHz.

That 86 and  259 look to be a 3:1 relationship. So it might be a room mode?
1125 ft/sec / 259 = ~4 ft (wavelength).
The 86 Hz would equate to a wavelength of ~12-1/2 feet. That seems like a smallish room?
(I often get this crap wrong by a factor os two, so it could be a 25 foot dimension)

Usually the <200Hz peaks are from room modes.

If it is a rectangular room, then Google “room mode calculators” and poke in the dimensions.
You can change the FFT size to get more resolution in the low frequency bins.
And also go lower FFT size to sort of smooth the very high frequencies…

It is kind of related to the whole deal about marching the subwoofer around a room to get a decent response (a.k.a. “walking the sub”).

[Paul S.]

Thanks so much. The room is actually 13x19 but I have a 16 ft ceiling. I will try to take another measurement. 

[TomicTime]

@Richard Vandersteenis the in room expert…but room gain is present at low end and where is you mic ? if at listening position and how far away from speakers ?

[TomicTime]

also use Vandertones and RS analog for the < 120 hz work with  mic at listening position. Careful your chair is not at a null point, our housekeeper moves mine back into the null….ask me how i know…ha.

[Paul S.]

Use vandertones even if I don't have a sub 3? What is rs analog? 

[Holmz]

23 minutes ago, Paul S. said:

What is rs analog? 

Radio shack meter I suspect…

 

24 minutes ago, Paul S. said:

Use vandertones even if I don't have a sub 3? …

I would probably try it, so you get the specific tones then, and can EQ them in amplitude.
The pink noise, or pseudo random noise is better for Dirac phase EQ, but the speakers should not need a lot of correction, as they are already correct.

If you were using a ported sub, or some arraignment with a lot of group delay, then you would need phase EQ on the sub.
But the Vandy subs seem like sealed, and I suspect that the group delay is low, which means you should only need amplitude EQ.

Are you running a sub? Or just the speakers? (I lost track).
 

[Paul S.]

I am running 2ce signatures with a 2wq sub. I think my last graph was pink noise. Here is another shot i took. BTW happy new year and thanks for the help 

[Holmz]

• The little peak at 2.2kHz is narrow enough not to worry about.
• I would think that a bit more boost at the bottom would be better.
• Is the sub running?
  • If not, then the XO would be trailing the main speakers off
  • You probably want a larger FFT size for the low freqs…
    (1k is great for the right hand side though) 
• It may be better to limit the Y-axis for -90 to -50.
  • Most house curves have a linear taper from 100Hz to 20kHz, and maybe a bump up under 100Hz (Depending on gendre.)

Happy New Years to you-n-yours as well.

[Paul S.]

Thanks. Yes the sub is running. Its hard to get the room pressurized becaise of the high ceiling and my rear wall has an opening to my dining room area. I could try to boost the db setting on the sub a bit. I believe i am using a 50 ohm high pass filter on my amp if that matters. 

[Richard Vandersteen]

Happy New year.  We start with the folly of room measurements which are mostly meaningless above 200Hz.  Our ear/brain hears and puts a priority on all sounds that come directly from the source.  As an example, in the room measurement above with a peak near C7 on the piano DSB room equalization would attempt to reduce this peak but if there actually was a piano in the room would the pianist actually hit the keys around C7 with less force?  Would this sound better?  To our ear/brain this would not sound better and is no way to correct for room aberrations.  Below 200 Hz the ear/brain hears the room and the source homogenized (because the wavelengths are long) so room correction will always sound better.  Careful use of diffusion, placement of the speakers and the listening position with analog room EQ below 200Hz has yielded the best results for me after 40+ years of research including DSP.  The complex processing required for room EQ is not sonically free even in a digital system.  Once the improvement in the bass is accomplished otherwise (our system) the sonic degradation of DSP is obvious.  Easy to prove if you have Quatro's and above by doing the room EQ per the manual and then have a friend bring his Dirac which will have very little positive to do but will still be in the signal path.  Now switch it in and out of the system.  Trust me you won't need to be an audiophile to hear the difference.  Early in the development of the Model 5 we discovered the high-pass all analog audio path but I wanted to do the bass room EQ with DSP thinking then it could be automated.  Wrong!  First there needed to be a way to delay the high passed main signal for this to work, which is not possible without using what's called a "Bucket Brigade" circuit (not good) so this failed.  Another discovery was the DSP never found the same correction even if nothing changed in the room and discovered a moving target does not render a stable sound stage.  This is all fun and why our products are what they are, YMMV.   Oh, BTW I have found that a good sounding room will be up in the bass (because of room gain), reasonably flat + or - 4Db through the midrange and tapering 4.5 Db to 20K (because of high frequency attenuation through air per wavelength) and not be over damped.

RV

[Richard Vandersteen]

2 minutes ago, Richard Vandersteen said:

Happy New year.  We start with the folly of room measurements which are mostly meaningless above 200Hz.  Our ear/brain hears and puts a priority on all sounds that come directly from the source.  As an example, in the room measurement above with a peak near C7 on the piano DSB room equalization would attempt to reduce this peak but if there actually was a piano in the room would the pianist actually hit the keys around C7 with less force?  Would this sound better?  To our ear/brain this would not sound better and is no way to correct for room aberrations.  Below 200 Hz the ear/brain hears the room and the source homogenized (because the wavelengths are long) so room correction will always sound better.  Careful use of diffusion, placement of the speakers and the listening position with analog room EQ below 200Hz has yielded the best results for me after 40+ years of research including DSP.  The complex processing required for room EQ is not sonically free even in a digital system.  Once the improvement in the bass is accomplished otherwise (our system) the sonic degradation of DSP is obvious.  Easy to prove if you have Quatro's and above by doing the room EQ per the manual and then have a friend bring his Dirac which will have very little positive to do but will still be in the signal path.  Now switch it in and out of the system.  Trust me you won't need to be an audiophile to hear the difference.  Early in the development of the Model 5 we discovered the high-pass all analog audio path but I wanted to do the bass room EQ with DSP thinking then it could be automated.  Wrong!  First there needed to be a way to delay the high passed main signal for this to work, which is not possible without using what's called a "Bucket Brigade" circuit (not good) so this failed.  Another discovery was the DSP never found the same correction even if nothing changed in the room and discovered a moving target does not render a stable sound stage.  This is all fun and why our products are what they are, YMMV.   Oh, BTW I have found that a good sounding room will be up in the bass (because of room gain), reasonably flat + or - 4Db through the midrange and tapering 4.5 Db to 20K (because of high frequency attenuation through air per wavelength) and not be over damped.

RV

Forgot to mention a saddle dip between 100 and 400Hz because of floor bounce (a natural occurrence to any sound created on a floor) and have discovered if you try to fill this dip it will make vocals sound boxy and overly resonant.

RV 

[Paul S.]

Thanks for the insight Richard. I have experienced the same results with dsp using my anthem arc calibration. Anthem is supposed to be one of the best but I found it sounds better watching movies with it off vs on. I use a separate preamp for 2 channel with no room correction and its a world of difference. Being that i have the speakers set up in the room as close to the manual that i can shows in the results. Im going to try to adjust the input sensitivity on the 2wq from here. I have a clearer understanding of how this works now which was my intention in using the analyser. Im glad to see that you have pointed out that measurements arent everything as i want the sound to be as natural as possible vs looking good on a graph! 

[TomicTime]

😉 Yes analog Radio Shack SPL meter.  The controls on the sub do allow for seasoning to taste. in my room with a strange ceiling, odd shapes and many openings, i find a Q of .7 to work…Experiment w level, small tweaks to EQ, room gain reinforcement and Q. Best to you

Jim

[Holmz]

@Paul S.do you have a DSP?

As RV alluded to, the direct path is something we hear separately from the reflected sounds if the reflections are not too close.
(One could take the speaker out into a field, on a stand, and EQ the amplitude without the effects of room reflections. And then what we would hear from the direct path (the in the room) would be with a flat frequency response.)

As someone already computed PEQ values for the 2C, so if you had DSP it would be interesting to implement those.
(Which I am intending to try, but the speaker and amps are ~2000 miles away from me at the moment.)

Maybe we would loose more than we would gain, but it could be interesting.

[Paul S.]

As I mentioned to RV i have an  anthem receiver for HT (my system does HT and 2 channel) and i tried arc on both full spectrum and below 300hz. In the end i ended up removing the DSP RC because it sounded better withoit it. Now that i finally found the correct placement for my soeakers in the room maybe i need to do it again and see what the results are but it wouldn't benefit me for 2 channel listening. 

[Holmz]

10 hours ago, Paul S. said:

As I mentioned to RV i have an  anthem receiver for HT (my system does HT and 2 channel) and i tried arc on both full spectrum and below 300hz. In the end i ended up removing the DSP RC because it sounded better withoit it. Now that i finally found the correct placement for my soeakers in the room maybe i need to do it again and see what the results are but it wouldn't benefit me for 2 channel listening. 

That is great to know. (Thanks!)

I am reading this a lot where the EQ correction for 2 channel results in gains that have more negatives elsewhere than benefits in the <200Hz region.

[Richard Vandersteen]

38 minutes ago, Holmz said:

That is great to know. (Thanks!)

I am reading this a lot where the EQ correction for 2 channel results in gains that have more negatives elsewhere than benefits in the <200Hz region.

Not if you own an upper end Vandersteen or a SUB THREE with room EQ.

RV

[Holmz]

I’ll check the lotto numbers tomorrow. 😄
WRT the 2C/Ce and @Paul S.anthem, or my Lyngdorf for HT… then it is a bit different from a system that was designed as a whole.

I am not sure which sub I have, but it is 20+ years old Vandy one, with the XO box before amp and the, high level inputs are attached to the speakers.  

 

But basically I was thinking of more like a mini DSP or other DSP set up without a sub as integrated as a Vandy sub. So with some other sub.
And also with trying to bi-amp the 2C and using a DSP to remove then low freq content from the MR/tweeter side.
(I suppose I can also do that just using a simple capacitor… Maybe I should try that? In order to free up the bass from taking up all the voltage.)

But then I have also hear that the bass really needs the same amplifier signature to sound good and integrated, so I am back to considering whether to sell the 2Cs and fund an upgrade… or just trying to hot rod them. I have a couple of DSPs kicking around, so maybe I should carve out some time?

Edited January 3, 2022 by Holmz

[GdnrBob]

 

17 hours ago, Richard Vandersteen said:

Not if you own an upper end Vandersteen or a SUB THREE with room EQ.

I keep forgetting to ask, but why are Vandy subs using RCA inputs instead of Spades, like the speakers?

 Bob

[Richard Vandersteen]

Depends on which sub and application.  The input on the 2W, 2Wq, SUB THREE and SUB NINE is speaker level but very high impedance (low current) so banana plugs are fine (good enough for a scope input) and the V2w is used with A/V receivers/processors RCA inputs.

RV 

[GdnrBob]

52 minutes ago, Richard Vandersteen said:

The input on the 2W, 2Wq, SUB THREE and SUB NINE is speaker level but very high impedance (low current) so banana plugs are fine

I can understand the reasoning, but knowing that spades can be connected more securely, I wished that the subs had binding posts that allowed use of both.

Another 2 cents...B

[Richard Vandersteen]

1 hour ago, GdnrBob said:

I can understand the reasoning, but knowing that spades can be connected more securely, I wished that the subs had binding posts that allowed use of both.

Another 2 cents...B

You're in luck but it will cost more than a few cents!  The SUB NINE does have 5-way binding posts that will accept spades.

RV

[GdnrBob]

56 minutes ago, Richard Vandersteen said:

You're in luck but it will cost more than a few cents!  The SUB NINE does have 5-way binding posts that will accept spades.

RV

Dagnabbit!😝

[ctsooner]

Go for it Bob they be a perfect addition