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CuznEddy Cinema Project Begins - Page 44

post #1291 of 1619
You may have already done this, but just in case: for measuring just the sub response, turn off smoothing, as it may mask some narrow peaks and nulls.
post #1292 of 1619
Thread Starter 
Quote:
Originally Posted by RTROSE View Post

Thanks for the info. Maybe through all of this you can become a CREW (Certified Room EQ Wizard). I am going to have to do a lot more searching/learning/reading on the subject.

Regards,

RTROSE

RT,

I will be declining any/all nominations for a CREW title. WAY too much to comprehend and master. Thru trial and error I'm just hoping to end up with some "practical gains"
post #1293 of 1619
Thread Starter 
Quote:
Originally Posted by Brad Horstkotte View Post

You may have already done this, but just in case: for measuring just the sub response, turn off smoothing, as it may mask some narrow peaks and nulls.

Thanks Brad - something I need to look out for. Due to a recent ejector pit pump failure in my basement; my "EQ" efforts have been delayed a few days.
Fortunately - I caught it before we had any water events!
post #1294 of 1619
Quote:
Originally Posted by cuzed2 View Post

Thanks Brad - something I need to look out for. Due to a recent ejector pit pump failure in my basement; my "EQ" efforts have been delayed a few days.
Fortunately - I caught it before we had any water events!


Man just the thought of this makes me shudder! Glad that you were able to catch the problem before it was an "issue"

Well whether or not you get the title is not up to you, it is left to the general masses or an individual so you may get the title like it or not.

Looking forward to seeing more graphs and your attempts at making you space more sonically appealing.

Regards,

RTROSE
post #1295 of 1619
Thread Starter 
RT,

I knew my pump failure would grab your attention. This particular ejector pump was only for the waste drains for my basement bathroom and powder room. I knew something was amiss when; after considerable water draw in the bathroom, the pump did not run. (As a test - I know that 2 toilet flushes should "cycle my pump")

So; I simply shut down the water supply to the bar and bathroom. Then last night
I determined the rarely used, 4 yr old sewage pump did indeed die. Bought a heavy duty cast iron replacement unit at lunch time today, and hope to be back to normal soon...
post #1296 of 1619
Glad you caught your pit problem before there was a real problem. Looking forward to reading your comments about getting your subs worked out. I've never messed with sound setup much so I need to learn all I can. Get er done
post #1297 of 1619
Quote:
Originally Posted by cuzed2 View Post

RT,

I knew my pump failure would grab your attention. This particular ejector pump was only for the waste drains for my basement bathroom and powder room. I knew something was amiss when; after considerable water draw in the bathroom, the pump did not run. (As a test - I know that 2 toilet flushes should "cycle my pump")

So; I simply shut down the water supply to the bar and bathroom. Then last night
I determined the rarely used, 4 yr old sewage pump did indeed die. Bought a heavy duty cast iron replacement unit at lunch time today, and hope to be back to normal soon...

Yup,

I stay very in tune to my pumps (or at least I try to) as I know failure brings a multitude of headaches. I can sleep through a thunderstorm, but have my pumps alarms go off and I'm wide awake to investigate.

Again I'm glad that you were aware of the situation and it did not become a much bigger issue.

Now don't you have some room measurements to take?

Regards,

RTROSE
post #1298 of 1619
Thread Starter 
Update,

The ejector pump for my downstairs bathroom and bar sink, has been resolved. For the pump replacement I went with a heavier duty unit (cast iron instead of the original stamped sheet metal/plastic construction). Big bonus in going with the heavier duty cast iron pump >> MUCH QUIETER!! The old setup sounded like a garbage disposer running, the new one is just noticeable.

I hope to resume some sub-woofer graphs and EQ stuff during the weekend
post #1299 of 1619
Glad to hear you got the pump issue resolved. What would cause a rarely used 4yr old pump to go bad? Paranoia on this end!
post #1300 of 1619
Thread Starter 
First of all; I am afraid it was a very cheap pump. And another factor was probably because it was rarely used (on average only 1~2 per week?)

Aside from pump issues - Wishing everyone a Belated Happy New Years on your side!!
post #1301 of 1619
Quote:
Originally Posted by cuzed2 View Post

First of all; I am afraid it was a very cheap pump. And another factor was probably because it was rarely used (on average only 1~2 per week?)

Aside from pump issues - Wishing everyone a Belated Happy New Years on your side!!

Happy New Years to you as well.

Pumps can fail from lack of use as well as wearing out. Sounds as though 1 to 2 times a week should have been enough to keep everything in good working order. However if it is mechanical, at some point it will fail. THAT is inevitable.

No paranoia needed, just vigilance.

Regards,

RTROSE
post #1302 of 1619
Thread Starter 
OK back to sharing the results of my recent audio tweaks:
What is making this fun is being able to see the low frequency room response in near real-time on the SMS-1.

The initial graph below seems to correlate rather well to my earlier REW attempts, especially that nasty null around 125Hz!


I had previously messed with changing the height and placement of my RF35 mains and observing with REW, at that time I found that I could somewhat minimize that 125Hz dip. So this past week; I experimented further while watching the SMS-1 to see if I could affect what was going on with my mains. One of the tests involved moving a roll of unused linacoustic around in front of the mains.


Although I didn't save the graph i could see on the SMS-1 that I was minimizing and shifting the frequency of the 125Hz null. I could also make similar improvements by increasing the height of the mains and pulling them about 12" further away from the the front wall. SO this was my test arrangement:




Below is the resulting graph after repositioning the mains. With repositioning alone; the 125 Hz null shifted to the left, and was reduced from a 13db did to about a 10db dip. The tape mark on the photo below marks the original excursion of the 125 Hz null.


I then went one step further; I raised the crossover frequency on my Marantz from 80Hz to 120Hz and then used the Velodyne slider to try and add some sub-woofer boost into the crossover area near the 120Hz null. The graph immediately above shows the affects of both efforts (placement and boosting the sub-woofers to help with the null). Both changes now appear to have reduced the 125 Hz null from 13db dip to about a 5db dip? I also diddled with boosting the 60Hz null (from 5 db to about 2.5db)

The one thing that I am becoming sure of is; that the original 125Hz null and the 60Hz null (also now boosted); are artifacts that are characteristic of my room. Side note; One needs to be very careful when trying to boost nulls; that one does not overdrive a sub-woofer, cutting the peaks is a better approach whenever possible.

I then diddled some more with a modest boost to the lowest frequencies, and then re-watched some of the my favorite low frequency movie scenes. The result brings a smile to my face
Next up: I need to revisit some measurements with REW to see my entire response from 10Hz to 20Khz
post #1303 of 1619
Thread Starter 
So last night I (attempted) to go back and make some comparison REW measurements. I was hoping to see what difference repositioning my mains might have made. First graph is from June of last year before I tinkered with re-positioning and raising the mains:


The next one is a hasty measurement made last night with the mains raised 5" and moved further away from the front wall:

It is also apparent that I am still learning how to use REW (as you can see above; last night I had a gross issue with my SPL/db level being mis-calibrated) didn't notice this until I had taken everything down. Assuming last nights data is somewhat valid; it seems that repositioning the mains did flatten things down a bit?

Please note these were taken full range of the mains only (no crossovers, no subwoofer signals, and therefore the Velodyne SMS-1 was not in play).
Open to all suggestions & comments, especially on what I am doing and doing wrong with REW
post #1304 of 1619
Ok,

I understand that a flat line is optimal. Is that flat line representing that all frequencies are at a specific db level say 74 in your first example. In the same example you have a fall off around 35 hz because you are not using a sub and then a roll of at 1.5k due to the room or speaker? Why choose 74 db? You will have to forgive me as I am really really new to all of this and I in no way understand any of it.

Regards,

RTROSE
post #1305 of 1619
Ed long time no talk. Hope all is good. Im actually in the middle of the beginning of my new build so you will have to stop by this summer

Build threads to follow as time allows.

Glad to see you plunging into measurements and room correction where the fun really lives.

My hunch is your null is shared by most its just audibly invisible until you see the picture. That one is most likely caused by the quarter wave reflection off the back wall from your mains. You'll know if you can easily move it around by shifting them closer or farther from the wall. Short of building them into a baffle wall or bringing them way out in the room chances are you can move or lessen the null but not eliminate it.
post #1306 of 1619
27 inches from speaker to rear wall is close for 125hz. Im assuming your mains are close to that range.
post #1307 of 1619
Thread Starter 
Quote:
Originally Posted by RTROSE View Post

Ok,

I understand that a flat line is optimal. Is that flat line representing that all frequencies are at a specific db level say 74 in your first example. In the same example you have a fall off around 35 hz because you are not using a sub and then a roll of at 1.5k due to the room or speaker? Why choose 74 db? You will have to forgive me as I am really really new to all of this and I in no way understand any of it.

Regards,

RTROSE

RT,
Hey good to see you are becoming a student in this arena of acoustics, REW, equalizing, room treatments, etc.. (I still feelvery much like the dunce in the corner)

You are correct in that a flat line is desirable, once that is achievable people even go farther by adding something called "house curves" to suit their tastes. For movie watchers it is also common to boost the LFs by a few db. Nothing magic about 74db; however; it seems most people like to establish a reference volume around 80db. I need to get more proficient with REW. I then intend to repeat my setups and adjustments using a reference level of 80db, and then repeat all my measurements with prettier documentation.
post #1308 of 1619
Thread Starter 
Quote:
Originally Posted by zamboniman View Post

27 inches from speaker to rear wall is close for 125hz. Im assuming your mains are close to that range.

Zamboniman,
It's great top hear from you. I hope all is going well for you and your family!!
Please don't hesitate to PM me if you are ever looking for some build assistance or a helping hand.

Your comment above seems to be right on the money with what I have discovered thru tinkering around. I was also surprised to see that I could affect that null by raising the height of the mains. The following quote is very fitting [B]"My hunch is your null is shared by most its just audibly invisible until you see the picture"[/b] Classic!
post #1309 of 1619
Thread Starter 
How's this for a low tech, cheap project?
Last week's "measurement-tinkering" convinced me that there was some definite benefits in raising my main speakers. I already had everything I needed except for some black carpet to cover the platforms. So for $9.00 at Menards, I found some pliable black carpet that is sold by the foot.

First step was to use a belt sander to radius the corners of the platforms:




The rest was pretty straightforward, trickiest part was to get a nice straight cut for what would become the seam along the top edge:


Started by stapling one end of the carpet strip to the back side of the platform. I then used adhesive spray to glue the rest around the perimeter of the platform.


And then glued the top piece on:


Not bad for $9.00 and a few hours of piddling around


post #1310 of 1619
Hey,

You are talking my language, low tech cheap projects are awesome. I really like your solution to your search for audio nirvana. They turned out really nice too. Well done.

Now don't you have some more graphs to make and publish?

Regards,

RTROSE
post #1311 of 1619
Thread Starter 
Ah yes - my nemesis;
Trying to get some decent "calibrated" REW graphs ........
post #1312 of 1619
Nice. Now don't you have a masking project to build?
post #1313 of 1619
Thread Starter 
Quote:
Originally Posted by Wazzey View Post

Nice. Now don't you have a masking project to build?

DAMN !!
It's impossible to sneak anything past this group. Wazzey - you're correct and I'm busted. You will be the first to know when my masking project starts in earnest - because I will be pestering you often for advice
post #1314 of 1619
Rose im'd me and said he needed help keeping you on your toes.
post #1315 of 1619
DOH! Now you weren't supposed to tell him Wazzey that was supposed to be our little secret. I think we all need a little extra motivation at some points in time now don't we?

Regards,

RTROSE
post #1316 of 1619
The stands are genius.
post #1317 of 1619
Quote:
Originally Posted by cuzed2 View Post

So last night I (attempted) to go back and make some comparison REW measurements. I was hoping to see what difference repositioning my mains might have made. First graph is from June of last year before I tinkered with re-positioning and raising the mains:

The next one is a hasty measurement made last night with the mains raised 5" and moved further away from the front wall:

It is also apparent that I am still learning how to use REW (as you can see above; last night I had a gross issue with my SPL/db level being mis-calibrated) didn't notice this until I had taken everything down. Assuming last nights data is somewhat valid; it seems that repositioning the mains did flatten things down a bit?

Please note these were taken full range of the mains only (no crossovers, no subwoofer signals, and therefore the Velodyne SMS-1 was not in play).
Open to all suggestions & comments, especially on what I am doing and doing wrong with REW

Hey Cuz,

i know your pain with measurements and the frustration of not getting that graph as flat as you would like.

Your graphs dont look too bad though..... How about a waterfall of the last graph?

I assume your crossing 80 or higher since your mains have a big peak below that?
post #1318 of 1619
Thread Starter 
Quote:
Originally Posted by tony123 View Post

The stands are genius.

Thanks Tony,
"Genius" seems quite generous - but I'll take it
I had a bunch of mdf and particle board laying around that needed a home.
Worked out great because that stuff is heavy - the finished pedestals weigh about 23 lbs. each
post #1319 of 1619
Thread Starter 
NicksHitachi,
Thanks for the input. Still trying to get my head around REW, a few responses below

Quote:
Originally Posted by NicksHitachi View Post

Hey Cuz,

i know your pain with measurements and the frustration of not getting that graph as flat as you would like.

Your graphs dont look too bad though..... How about a waterfall of the last graph? I have no idea how to go about doing a waterfall? - next time out with REW, I'll have to tinker some more

I assume your crossing 80 or higher since your mains have a big peak below that?

I'm crossing at 120Hz now, seems to help to have the subs pickup some of this "dip", especially with 3 subs spread around the room.
post #1320 of 1619
Quote:
Originally Posted by cuzed2 View Post

NicksHitachi,
Thanks for the input. Still trying to get my head around REW, a few responses below

I'm crossing at 120Hz now, seems to help to have the subs pickup some of this "dip", especially with 3 subs spread around the room.

ahhh ok i wondered if it might be smoother crossing in that range.

FYI you can generate the waterfall from old stored measurements. Open measurement, click on waterfall tab, click generate button bottom left, and itll generate the waterfall from the measurements.

Pay attention to how far the graph comes out at you. The more it does the more ringing you have at that frequency. Ill bet most of those dips/peaks have significant ringing which causes reaponse anomalies. Any ringing past 300ms is Bad. The lower you can get it generally the better.

Oh, and not nitpicking, convention is to post FR graphs with a 60db span on the axis scale, This helps orient folks when interpreting your graphs.
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