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building home studio advice needed
Old 26th May 2010
  #301
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johndykstra's Avatar
 

can you also take full range response graphs with only one speaker at a time, and put both measures on one graph, as well as separate?
Old 26th May 2010
  #302
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for low freq. waterfalls, it is good to have both speakers on. But for frequency response graphs, the picture is more accurate with only one speaker, as your microphones doesn't have a skull between two ears to block cancellation caused by two arriving signals...make sense?
Old 27th May 2010
  #303
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hi john,

Quote:
At that point, if you can in sketchup, put some colored circles on the walls to show me where particular frequencies seem to be ringing loudest.
SURE

Quote:
Is there any ambient noise in the room with the speakers off? Still wondering where these are coming from.
AFTER TEMPORARILY CLOSING THE DOOR THERE IS STILL SPACE LEFT. I WILL TRY TO SORT OUT THIS.

Quote:
can you also take full range response graphs with only one speaker at a time, and put both measures on one graph, as well as separate?
FINE. NOW I WILL TAKE OUR 3RD MEASUREMENT AS A STARTING POINT.

I WILL GET BACK SOON WITH ALL THESE. THANKS
Old 27th May 2010
  #304
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shortyedwards's Avatar
 

gee whiz ... some pics of all this sure would be nice as some of us are following it.
Old 27th May 2010
  #305
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hi john

here are the measurements

only left speaker playing full range

building home studio advice needed-only-left-speaker-full-range.jpg

only right speaker playing full range

building home studio advice needed-only-right-speaker-full-range.jpg

comparison

building home studio advice needed-comparison-speakers.jpg
Old 27th May 2010
  #306
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Regarding that ambient noise i noticed that there is a very low frequency vibration coming from the room which is beneath the control room. that's noise is of a fan which is not in a good position and making noise. i will change that. i have taken two waterfall measurements.

waterfall with fan's vibration

building home studio advice needed-waterfall-fan.jpg


waterfall without fan's vibration

building home studio advice needed-waterfall-without-fan.jpg

i think sub bass areas are affected
Old 27th May 2010
  #307
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i have worked on 2 frequencies.

50 Hz is red color and 150 Hz is blue color. i have tried to mark points in sketch up but the work is very dirty. i have marked all the measurements so you can guide me for the rest 2 frequency's measurements. the guide points in the centre are final points. measurements above and below these points are not showed correctly but they had been taken in the symmetry of the centre guide point. central measurements are given and others are near top corner and bottom. the 150 Hz measurement is taken exactly on the same 50 Hz points. due to inability of working in sketch up i have marked these points here and there. but the idea is there.

sorry for this inaccuracy.
50-150 .skp
Old 27th May 2010
  #308
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great job Amit, very thorough. I'll digest these and get back to you. As expected, the readings are higher closer to the speakers... this makes sense. Truthfully, I expected a larger variation from place to place, but it is what it is.

Regarding the other frequencies, you can mark only the readings that are of a greater magnitude than expected...i.e. if there's an area that is say 76db closer to the speaker, but further away it raises to 82... these are the anomalies we are looking for.
Old 27th May 2010
  #309
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I wonder if your speaker crossover is at 1.5k? Have you been seeing a pretty consistant dip there? Also, is the right side speaker's hf adjustment matched to the lefts?
Old 28th May 2010
  #310
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Quote:
Originally Posted by [email protected] View Post
I wonder if your speaker crossover is at 1.5k? Have you been seeing a pretty consistant dip there? Also, is the right side speaker's hf adjustment matched to the lefts?
ROLAND DS 90 A

Crossover Frequency 2.6kHz (active fourth order)

RESPONSE GRAPH

building home studio advice needed-roland-ds-90-response-graph.jpg


EDITED

Quote:
Also, is the right side speaker's hf adjustment matched to the lefts
YES as visible. these speakers are not having stepped controls. so small difference may be there.
Old 28th May 2010
  #311
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amit,

attached is a highly simplified version of the room. it may help you when posting loudness thresholds.

if you can, in this next series of frequencies, try to make sure that the computer is playing them at equal volume to the first two... that's to say, your level meter on the computer, not on the spl meter.
Attached Files
File Type: skp amitsimple.skp (580.1 KB, 98 views)
Old 28th May 2010
  #312
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Quote:
Originally Posted by shortyedwards View Post
gee whiz ... some pics of all this sure would be nice as some of us are following it.
glad to know someone is following... this was starting to feel like a private conversation.

any and all input is welcome
Old 28th May 2010
  #313
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hi john

THANKS FOR THE FILE.

i am using my laptop for all the measurements. windows suddenly gave problem and the laptop needs to be formated. i will format it tomorrow morning and take measurements afterwards. (all cds are at my working place). sorry for this unexpected delay.
Old 29th May 2010
  #314
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hi john,

here are the remaining 2 measurements. ( 200-350)
i felt like giving all the measurements.

upper reading in red color is 200 Hz.
lower reading in blue color is 350 Hz.

200-350 copy.skp

slightly moving the spl metre changes the readings as we move the spl meter towards bottom corner touching the floor there is 1-2 db of increase in every frequency.
Old 29th May 2010
  #315
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thanks amit.
Old 1st June 2010
  #316
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Hi Amit.

I've been needing to do a bit of reading... as it turns out, even with a full 1' of thickness, slat absorbers need to be massive to hit 50hz... We're talking like a slat width of 3'.

I've been looking into other options. Sorry buddy, I wish there was better news to report, but hang in there, I won't let you down.
Old 1st June 2010
  #317
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Quote:
Originally Posted by [email protected] View Post
Hi Amit.

I've been needing to do a bit of reading... as it turns out, even with a full 1' of thickness, slat absorbers need to be massive to hit 50hz... We're talking like a slat width of 3'.

I've been looking into other options. Sorry buddy, I wish there was better news to report, but hang in there, I won't let you down.
HI JOHN,

please take your time. after working hard on song tracks we cannot ignore the mixing and mastering process (due to my time restriction) . i will give carpenters a short break so that we can finalize on the plans.

THANKS

EDITED
Old 2nd June 2010
  #318
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Hi Amit.

I have started a thread over at the sayer's forum. just want to keep you abreast to all developments.

John Sayers' Recording Studio Design Forum • View topic - How to tame 50hz with a 1' depth
Old 2nd June 2010
  #319
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Quote:
Originally Posted by [email protected] View Post
Hi Amit.

I have started a thread over at the sayer's forum. just want to keep you abreast to all developments.

John Sayers' Recording Studio Design Forum • View topic - How to tame 50hz with a 1' depth
hi john

now i am in touch with your thread.

I HAVE ALSO STARTED A THREAD IN HELPSLUTZ FOR FINDING A WORD WITH MORE DEPTH THAN THANKS. AS SOON AS I FIND THE WORD I WILL GET BACK TO YOU.

THAN...... NO I WILL FIND ANOTHER WORD
Old 2nd June 2010
  #320
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Amit you're a great guy. It's been a pleasure working and learning with you.
Old 2nd June 2010
  #321
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I have nothing to add to this discussion other than mentioning how cool the giant Boss BR600 is in your mock-up. That think has to be about triple size!
heh
Old 3rd June 2010
  #322
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As we've learned over at the Sayer's forum (thanks Ethan!), our 50hz problem is dirty electrical. It also probably explains the remaining razor peaks that were there after you turned the fan off.

Does anybody out there know how to clear this up?
Old 5th June 2010
  #323
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Amit.

I'm not comfortable reading information on the internet regarding advice on electrical wiring and passing that along to you as something you should be doing. This is a matter I think you should take up with your electrician.

The term "star grounding" or "star earthing" seems to refer to a practice in which every outlet has a dedicated ground wire that doesn't bridge from outlet to outlet. Being I've never done any wiring, this is not something I can visualize how to actually achieve, and wouldn't know where to start. Again, talking this over with the electrician would be a good idea.

We need to see a waterfall without the electrical interference before we can assess our next step, though I think once all of that is cleared up, we will be looking at a very clean waterfall, and will likely be able to apply slats as a high frequency treatment only... meaning that our plan as designed should be solid as is.

Mr. Sayers suggested that we build a secondary back wall. One that is 8" deeper than our existing one. Perhaps this is based on something he is seeing in the existing waterfall... something that and additional 8" would treat that we currently are not. I'm not sure.


One more thing. It troubles me that a thread on a different site got attention from major contributors to this site, yet for some reason, this thread remains a one on one discussion. I have guesses as to why there may have been feathers ruffled by myself over here, but can everyone keep in mind, this is Amit's thread. I'm sure he would like as much input as he can get.
Old 5th June 2010
  #324
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hi john,

thanks for all the efforts you are doing. i know that you want to take the construction perfection to the extreme. its very appreciable.

india lacks behind in terms of deep technical knowledge in this field. the electrical issue which we are facing now cannot be handled by the local electricians. they are even not aware of what i am talking about. i have to consult various electricians in the city and may be out of the city. this may take several days. the problem may be sorted or not. so i think we should assume the decays in waterfall to be electrical fault only and proceed with your plan( slats for high frequency treatment). now we know that 50 hz is dirty electrical which is the only frequency ringing at higher rms values. so this is not room problem. except this the waterfall response is very nice.

Quote:
meaning that our plan as designed should be solid as is.
yes john it is a solid plan
Old 5th June 2010
  #325
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and regarding that new wall idea i think the low frequency energy is already controlled. i am sure that the need will not come but in extreme case in future if the 50 hz is to be controlled , i think 1 or 2 panel membrane absorbers tunned to that particular frequency can be hanged.

what do you think john?
Old 5th June 2010
  #326
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I agree.

But in reality, it is wrong to assume that the waterfall is good. Is it possible to "lift" the ground and do a measurement? It's not recommended for long term use, but here, you can use an adaptor to eliminate the ground wire for outlets in older homes without a ground prong. I'm wondering if we can see a shot without the interference without implementing a long term fix immediately. This is all up to you though, as this is your room, and your investment.
Old 5th June 2010
  #327
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Amit.

If time permits, I'd really like to do one final drawing. Andre's comment about the slats creating new anomalies in the waterfall has got me thinking.

Though there is insulation directly touching the back of the slats, there is still likely to be some amount of resonance. Being that we have planned currently for all of the slats to be 4" wide, that is an incredible amount of the same resonance. I would like to render a version with a variety of slat widths, so any new resonance imparted will be less severe.

This will take me some time, (say end of next week), and would also mean a bit more work for the carpenters... $ ... I could offset that additional cost by limiting the side wall design to be a bit more simple... more like a hybrid of Mr Sayers file.

It's really up to you.
Old 5th June 2010
  #328
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Quote:
Originally Posted by [email protected] View Post
Amit.

If time permits, I'd really like to do one final drawing. Andre's comment about the slats creating new anomalies in the waterfall has got me thinking.

Though there is insulation directly touching the back of the slats, there is still likely to be some amount of resonance. Being that we have planned currently for all of the slats to be 4" wide, that is an incredible amount of the same resonance. I would like to render a version with a variety of slat widths, so any new resonance imparted will be less severe.

This will take me some time, (say end of next week), and would also mean a bit more work for the carpenters... $ ... I could offset that additional cost by limiting the side wall design to be a bit more simple... more like a hybrid of Mr Sayers file.

It's really up to you.

yes ofcourse john. please take your time. i will call carpenters next week or immediately after the plan is finalized.

john i am a bit confused about mr. sayers file. he has given no treatment to the first reflection points on the side walls. what can be the reason for this
Old 5th June 2010
  #329
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Quote:
Originally Posted by amit monga View Post
yes ofcourse john. please take your time. i will call carpenters next week or immediately after the plan is finalized.

john i am a bit confused about mr. sayers file. he has given no treatment to the first reflection points on the side walls. what can be the reason for this
I don't know. This is an area where the new file would more closely resemble my original rather than his. I was more referring to the simplicity of the slats.
Old 5th June 2010
  #330
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Quote:
this is an area where the new file would more closely resemble my original rather than his
thanks john. I also wanted this
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