100 hz dip - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #1 of 76 Old 07-15-16, 07:33 AM Thread Starter
Shackster
Matthijs
 
Join Date: Jul 2016
Location: Netherlands
Posts: 58
100 hz dip

Hi guys, i'll introduce myself as most of you dont know me.

My name is Matthijs, 28yo and i'm from the netherlands. (so my writing might nog be perfect )


Im currently setting up my new room which is meant for professional mixing purposes.

The lengt of my room is 5.65 (Meters)
The width is 3.48 (meters)
The highest point is 2,75 (its not a flat ceiling)

So with this information i made up some calculations where to put my speakers
and where would be my listening position. I had read the listening position should be around 30 till 38 % from your
front wall. So i did.

I placed everything (besides the lengt of course) exact in the middle and have setup the triangle as precice as possible.

My listening position is now at : 2.05 from the front wall which is 36 %

Im giving all this information becouse my graph gave me a big dip around the 100 hz and im being told i should experiment with
moving my listening position and or my speakers position. The only thing im concernt about is how to go about it becouse
every inch would make a big change in the symetry and even possibilities of placement.

So my question is, what would be the best and most effective way to find out where the dip is comming from whitout constantly changing my whole setup just to test if something changed, i mean there should be some guidelines right which makes things easyer ? Isnt there a way to find the source with the information given in the graphs ?

Here are some photo's of my measurements and the room im working in.

As you can see the dip is around 15 db, tho this is probably 5 db to much becouse my spl reading gives 5 db lower when doing the subwoover test.

I tried diffrenct mic placements with symetric angle towards my speaker, and i tried putting a absorb panel in front of my tv just to see if it does something with
reflections or buildups, and i checked to see if it makes a diffrence when i put my refference monitors away. Not big diffrences on all.
Attached Thumbnails
100 hz dip-overlays.png  

100 hz dip-img_3614.jpg  

100 hz dip-img_3612.jpg  

100 hz dip-img_3611.jpg  

100 hz dip-100hzdip.jpg  


Last edited by matthijs87; 07-20-16 at 11:49 AM.
matthijs87 is offline  
Sponsored Links
Advertisement
 
post #2 of 76 Old 07-15-16, 08:17 AM
HTS Senior Moderator
 
bpape's Avatar
Bryan Pape
 
Join Date: Sep 2006
Location: Wildwood, MO (St. Loui
Posts: 5,273
Send a message via AIM to bpape Send a message via Skype™ to bpape
Re: 100 hz dip

First, When you are making changes, all you move is the mic. If you move the speakers and the mic, you have 2 variables and no idea what changes are related to what. You always only want to only change one thing at a time. Also, you appear to have a very high level of smoothing applied which makes it pretty much impossible to determine really where things are. Turn the smoothing off when trying to identify where things are coming from.

I am serious... and don't call me Shirley.

Bryan Pape
Lead Acoustician

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
bpape is offline  
post #3 of 76 Old 07-15-16, 08:48 AM Thread Starter
Shackster
Matthijs
 
Join Date: Jul 2016
Location: Netherlands
Posts: 58
Re: 100 hz dip

Okay, thank you, that makes sense indeed.

I removed the smoothing, and of all tests moving the mic was the one which gave the best results.
i moved it 20 cm towards the speaker which gives me less spikes and is overall a bit better but it doenst look like the source of the problem.

Do you have any sugestions on how to find the source more accurate ?
Attached Thumbnails
100 hz dip-20cm-closer.png  

matthijs87 is offline  
 
post #4 of 76 Old 07-15-16, 08:56 AM
Elite Shackster
 
tonyvdb's Avatar
Tony
 
Join Date: Sep 2007
Location: Edmonton, Alberta, Can
Posts: 15,012
My System
Re: 100 hz dip

Just to understand a little more about your speaker setup are you using a small subwoofer?

Home theater:
Onkyo 805, Yamaha YDP2006EQ, Samson Servo 600 amp
3 EV Sentry 500 monitors across the front, 4 Mission 762i's Surrounds, SVS PB13U sub, Panasonic BDT220, Harmony 1100, Nintendo WiiU
Panasonic PT-AE8000 on a 120" 2,35:1 fixed screen

Living room system:
Sherwood/Newcastle R972, Mission 765's, SVS SBS02's, A/D/S MS3u sub, Yamaha YDG2030EQ
Yamaha KX-393 Tape deck, CDC 805 CD changer, Panasonic BD60, Sony turntable PS-T20
Panasonic TC-P50ST60, HD-PVR & WDTV Live, Harmony 900

tonyvdb is offline  
post #5 of 76 Old 07-15-16, 09:12 AM Thread Starter
Shackster
Matthijs
 
Join Date: Jul 2016
Location: Netherlands
Posts: 58
Re: 100 hz dip

No, im using Genelec 8050s , they produce more then enough sub so i dont need a subwoover
matthijs87 is offline  
post #6 of 76 Old 07-15-16, 09:17 AM
Elite Shackster
 
tonyvdb's Avatar
Tony
 
Join Date: Sep 2007
Location: Edmonton, Alberta, Can
Posts: 15,012
My System
Re: 100 hz dip

Bryan would be the best person to talk to but until he responds Im thinking because you have many reflective surfaces in the room that could be causing cancellation. Have you tried putting down a thick throw rug on part of the floor?

Home theater:
Onkyo 805, Yamaha YDP2006EQ, Samson Servo 600 amp
3 EV Sentry 500 monitors across the front, 4 Mission 762i's Surrounds, SVS PB13U sub, Panasonic BDT220, Harmony 1100, Nintendo WiiU
Panasonic PT-AE8000 on a 120" 2,35:1 fixed screen

Living room system:
Sherwood/Newcastle R972, Mission 765's, SVS SBS02's, A/D/S MS3u sub, Yamaha YDG2030EQ
Yamaha KX-393 Tape deck, CDC 805 CD changer, Panasonic BD60, Sony turntable PS-T20
Panasonic TC-P50ST60, HD-PVR & WDTV Live, Harmony 900

tonyvdb is offline  
post #7 of 76 Old 07-15-16, 09:32 AM
HTS Senior Moderator
 
bpape's Avatar
Bryan Pape
 
Join Date: Sep 2006
Location: Wildwood, MO (St. Loui
Posts: 5,273
Send a message via AIM to bpape Send a message via Skype™ to bpape
Re: 100 hz dip

How far are the speakers from the wall you are facing and what position is the mic in for this measurement?

I am serious... and don't call me Shirley.

Bryan Pape
Lead Acoustician

To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.
bpape is offline  
post #8 of 76 Old 07-15-16, 09:58 AM Thread Starter
Shackster
Matthijs
 
Join Date: Jul 2016
Location: Netherlands
Posts: 58
Re: 100 hz dip

Tonyvdb, thank you for your input, i tried the floor on diffrent locations but it didnt make any big changes, some frequenties went a tiny bit better but it also created extra spikes.

@ bpape : from front tweeter to wall is 1 meter (diagonal)
76 cm when measured from the back of the speaker. (diagonal)

Sidewall till tweater is 87 cm by the way.

My mic is pointing up.
matthijs87 is offline  
post #9 of 76 Old 07-16-16, 02:48 AM
Senior Shackster
lesmor
 
Join Date: Dec 2009
Posts: 153
Re: 100 hz dip

Quote:
matthijs87 wrote: View Post
Tonyvdb, thank you for your input, i tried the floor on diffrent locations but it didnt make any big changes, some frequenties went a tiny bit better but it also created extra spikes.

@ bpape : from front tweeter to wall is 1 meter (diagonal)
76 cm when measured from the back of the speaker. (diagonal)

Sidewall till tweater is 87 cm by the way.

My mic is pointing up.
I hazard a guess that going by 87cm that it could be a sidewall 1/4 wavelength cancellation?
Caveat being I am no expert and just trying to learn
lesmor is offline  
post #10 of 76 Old 07-17-16, 04:20 PM Thread Starter
Shackster
Matthijs
 
Join Date: Jul 2016
Location: Netherlands
Posts: 58
Re: 100 hz dip

How is that a 1/4 wavelength cancellation ? woudnt 1/4th be 25 cm ? or maybe im missing the point , but from what i have read is that the sidewall length shoudnt be an equivalent of the length from the wall behind the speaker. so if im right, that would mean cancelations would be most probably at 25, 50 75 in my case or maybe i didnt understand this part well enough, im curious as well
matthijs87 is offline  
Reply

Bookmarks

Tags
100 , dip , hz

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome