La Scalas - surprising SPL graphs

[wuzzzer]

Definitely disable YPAO and set your receiver to Direct or Pure Direct if you're able to.

[Dave MacKay]

12 minutes ago, captainbeefheart said:

It's quick and won't hurt anything to just remove the wires from the woofer to the crossover network on one speaker and reverse them. See if you get an improvement in sound and measurements.

Good idea. I'll try that.

[Dave MacKay]

4 hours ago, wuzzzer said:

Do you have everything disabled in your receiver such as Audyssey, dynamic EQ, or anything else that would be messing with the signal?

 

I re-ran the “base line” test after ensuring that all YPAO equalization on my receiver was off. TLDR, performance was more consistent, a little worse at high frequencies and somewhat better for bass, but bass is still weak.

 

I have overlaid yesterday’s results (in red) and today’s results (in blue) on the same graph. Here is the graph from 20 Hz to 20 kHz:

What I noticed was:

·         frequencies between about 500 Hz and 1000 Hz are about the same

·         frequencies above 1 kHz have dropped by about 5 dBFS

·         frequencies between 200 Hz and 500 Hz are also lower

·         although the drop-off below 200 Hz is still there, the slope is less steep

 

Since we are concentrating on the low frequencies, I have zoomed in to the portion of the graph between 20 Hz and 200 Hz:

There is no question that today’s results (in blue) are better than yesterday’s results (in red).

 

Today’s results show that:

·         my La Scalas perform at about -50 dBFS +/- 5 dB from 100 Hz to 17 kHz.

·         bass performance drops precipitously below 100 Hz. It’s down more than 10 dB by 50 Hz.

·         the La Scalas (with SMAHL tweeters and lenses) drop off slightly after about 17 kHz. That’s not a concern for me because it’s outside my hearing range.

 

From this, it’s clear that, although the Yamaha YPAO system improves performance above 1 kHZ, it significantly impairs bass performance.

 

I had wanted to be able to use YPAO because it enables me to specify where a cross-over frequency for LFE. And, sadly, the receiver’s user manual doesn’t specify what is sent out the LFE and when. I may have to contact Yamaha to see if I can continue to use the LFE output for my subwoofers, or if I’ll need to connect them in another fashion.

 

I’ll make another post with the results from flipping the woofer wiring on one speaker (to investigate phase issues).

[Deang]

See how happy you were before you started measuring, now look at you. 

[Dave MacKay]

4 hours ago, hanksjim1 said:

woofers out of phase?

 

3 hours ago, captainbeefheart said:

It's quick and won't hurt anything to just remove the wires from the woofer to the crossover network on one speaker and reverse them. See if you get an improvement in sound and measurements.

 

To see if the woofers in my La Scalas might be out of phase with each other, I reversed the positive and negative leads going to the woofer in my Right speaker. I flipped the leads at the network, as @captainbeefheart suggested.

 

TLDR, I’m not sure but I think the woofers were in phase.

 

I ran the test in direct stereo mode (i.e., all YPAO equalization turned off on the receiver). I’ve overlaid the base case (i.e., leads not swapped) in blue with the test case (i.e., leads swapped) in red on these graphs.

 

The graph shows the results of that change:

The blue and red lines are pretty close together above 125 Hz, but show some separation below that.

 

Here’s a zoomed in portion of the graph, showing 20 Hz to 200 Hz:

It seems to me that the blue lines (i.e., not swapped) look better.

 

From these graphs, is it possible to tell if my woofers were out of phase? I’m guessing they weren't, but am not sure.

[babadono]

4 minutes ago, Dave MacKay said:

 

From these graphs, is it possible to tell if my woofers were out of phase? I’m guessing they weren't, but am not sure.

that's a darn good question, looks like peaks and dips exchanged places, sort of.

Waiting to hear explanation from someone who knows.-----i.e. not me.

[Deang]

At this point, you should stop measuring the room and start measuring the speakers - one at a time.
 

Could we see 1/6 smoothing applied. 

[Rudy81]

Some of what you are looking at is the effects of your room on bass.  Other than doing some type of bass treatment, there is not much you can do to fix that problem.  

 

I HIGHLY encourage you to disable YPAO, although I don't have any experience with that system, after many years of working and struggling against Audyssey Pro, I got rid of it and have never looked back.  

 

If you get really motivated, and have some open space in your back yard, take one of your La Scala's outside and take a sweep outside.  Not quite an anechoic chamber, but will give you an idea of just how much your room affects your performance. I live on acreage, so fairly easy for me to do without any neighbor's houses close enough to affect the results. If you want to look at the theoretical expectation, use the REW room simulation to show you how your room dimensions affect the bass of your system.  

 

This is why the listening environment is what we should all focus on to optimize performance, not speaker cables or other snake oils. 

[captainbeefheart]

Looks to me like they were wired correctly to begin with and it wasn't an out of phase issue.

 

Dumb question time; Did you load the calibration file into REW before taking the measurements?

[wuzzzer]

That looks like room interaction now.  You should try moving your listening position to see if that helps smooth things out.

[Dave MacKay]

44 minutes ago, captainbeefheart said:

Dumb question time; Did you load the calibration file into REW before taking the measurements?

Yes, I loaded the calibration file. 

[Dave MacKay]

1 hour ago, Rudy81 said:

Some of what you are looking at is the effects of your room on bass.  Other than doing some type of bass treatment, there is not much you can do to fix that problem.  

 

I HIGHLY encourage you to disable YPAO, although I don't have any experience with that system, after many years of working and struggling against Audyssey Pro, I got rid of it and have never looked back.  

 

If you get really motivated, and have some open space in your back yard, take one of your La Scala's outside and take a sweep outside.  Not quite an anechoic chamber, but will give you an idea of just how much your room affects your performance. I live on acreage, so fairly easy for me to do without any neighbor's houses close enough to affect the results. If you want to look at the theoretical expectation, use the REW room simulation to show you how your room dimensions affect the bass of your system.  

 

This is why the listening environment is what we should all focus on to optimize performance, not speaker cables or other snake oils. 

The room certainly has issues and needs treatment. Because of WAF placement and room treatment are matters for negotiation. 

 

I'll discontinue using YPAO. I'll have to figure out how to meld my subwoofers into the system, but that's a challenge for another day.

 

 

[garyrc]

I agree that you should reverse the polarity just to see if the bass increases.

 

The La Scalas of that period were supposed to be highly similar in sound to the Belle Klipsch.  My Belle Klipsch (center channel) is good to about 60Hz, where there is a very small peak, then drops like a rock.

[Dave MacKay]

1 hour ago, Crankysoldermeister said:

At this point, you should stop measuring the room and start measuring the speakers - one at a time.
 

Could we see 1/6 smoothing applied. 

 

Here is the 20 Hz to 20 kHz graph with 1/6 smoothing. Blue is the base case (YPAO off) and red is the base case with the phase of one woofer swapped.

 

Here's a zoom-in from 20 Hz to 200 Hz of the same graph:

 

What should I look for when measuring the speakers one at a time?

 

[Rudy81]

As you can see in your graphs, the EQ is negatively affecting your response.  I suggest keeping the timing measurements for all your speakers, but do away with the EQ being applied.  

 

If you are concerned with a reversed driver, just run one speaker and see how it performs in the room.  With only one speaker running, the only interaction will be at the crossover frequency.  It happens, but is rare IMHO. that the drivers are wired wrong.  That, is generally very obvious.  If you want to prove to yourself that it is the room interaction with the frequencies, take several measurements at different room locations and focus in on the bass area below about 120Hz.  You will likely see some locations with great bass and other results with terrible response at the same frequency but a different measurement location.  

 

Using the REW room simulator, you MAY be able to find better locations for your speakers and sitting position.  Lot easier to move a mouse or track pad than the speaker and your couch.  

 

Be advised, you are entering a very deep and dark rabbit hole.....but rewarding once you understand the limitations and what you can do about them. WAF, however will be huge factor here.

[Rudy81]

BTW, the La Scala has plenty of bass down to 40Hz or so.  Below that, I preferred the Cornwall bass.  The Belle was the weakest in the bass department IMHO.  Of course, the Khorn trumped them, but they too had their limitations due to placement requirements.  At the outset, you just need to understand there is no PERFECT answer that will give you a perfect solution.  You can get close, but have to spend horrendous amounts of money to create a proper listening environment.  Room geometry and acoustics is where all the challenges and solutions lie.

[Rudy81]

I might suggest you focus on one headache at a time.  Take the subs totally out of the equation until you get the LaS dialed in.  Get the La Scalas placed so they give you the best possible performance within the limitations of your room and WAF.  THEN, and only THEN, go to the REW room simulator and set it up to mimic your room. Then, you will be able to play with the sub locations.  That software is particularly good at helping with sub placement.  With your subs at the front of the room, you are causing problems in the most difficult frequency ranges.  REW will likely suggest one sub up front and one near the back....no, not necessarily in the corners (WAAF again). 

 

If done properly, you should be able to place the subs to HELP with placement limitations of the La Scalas, thereby finding an optimal solution for your listening environment.  

 

Understand that this process will take quite a bit of time, but it will be worth the effort.  

[captainbeefheart]

1 hour ago, Rudy81 said:

I might suggest you focus on one headache at a time.  Take the subs totally out of the equation until you get the LaS dialed in.  Get the La Scalas placed so they give you the best possible performance within the limitations of your room and WAF.  THEN, and only THEN, go to the REW room simulator and set it up to mimic your room. Then, you will be able to play with the sub locations.  That software is particularly good at helping with sub placement.  With your subs at the front of the room, you are causing problems in the most difficult frequency ranges.  REW will likely suggest one sub up front and one near the back....no, not necessarily in the corners (WAAF again). 

 

If done properly, you should be able to place the subs to HELP with placement limitations of the La Scalas, thereby finding an optimal solution for your listening environment.  

 

Understand that this process will take quite a bit of time, but it will be worth the effort.  

 

My understanding he doesn't have the EQ on and he has his subs disabled.

 

He basically is starting out from the beginning with just the La Scala's.

[Rolox]

Most obvious cause would be reversed polarity at one of the woofers. While the Lascala bass doesn't go low, that curve is really weird and not representative of LaScala.

[Rolox]

If it is a room acoustics issue, then I would try putting the LaScala as close as possible to the front wall, and go from there. The only problem is: where will you put your subs?