📞 Call us for a free consultation! 520–392–9486, 8am – 6pm / Log in or Sign up / Contact
logo for room acoustics forum showing a waveform within a circle and the title of the forum
Avatar
Please consider registering
Guest
Search
Forum Scope


Match



Forum Options



Minimum search word length is 3 characters - maximum search word length is 84 characters
Register Lost password?
sp_Feed sp_TopicIcon
What Frequency Range Should I Diffuse ?
Avatar
Member
Members
Forum Posts: 1
Member Since:
April 4, 2019
sp_UserOfflineSmall Offline
1
April 4, 2019 - 4:50 pm
sp_Permalink sp_Print

Hi, I have made several spectral measurements in my mixing room and I have noticed the same problem. I Have a dip from 600hz to 2khz ranging from -1db to -4db. Should I make my diffusers in that range so I can reinforce those attenuated frequency’s by diffusing them? Let’s say i’m going to make a QRD diffuser that diffuses 700hz and cuts off at 2000hz. does it seem right ?

thank you for your videos !

Avatar
Chief Acoustics Engineer
Forum Posts: 387
Member Since:
August 12, 2013
sp_UserOfflineSmall Offline
2
April 6, 2019 - 11:17 am
sp_Permalink sp_Print

N,

Diffusion will not assist you with peaks and troughs in frequency response. It will actually make them worse. You must use broadband absorption to treat the issues.

Avatar
Member
Members
Forum Posts: 6
Member Since:
December 6, 2019
sp_UserOfflineSmall Offline
3
January 13, 2020 - 1:14 pm
sp_Permalink sp_Print

Dennis,

Are you sure about this? It seems to me that nadeau777 was on the right path with his suggestion.

As far as i know, the very main purpose of phase grating is to keep the energy within the room without disturbing the frequency response, by spreading the energy out in time.

Avatar
Chief Acoustics Engineer
Forum Posts: 387
Member Since:
August 12, 2013
sp_UserOfflineSmall Offline
4
January 15, 2020 - 10:14 am
sp_Permalink sp_Print

S, Diffusers can not add anything to the room response other than higher Rt-60 times.

Avatar
Member
Members
Forum Posts: 6
Member Since:
December 6, 2019
sp_UserOfflineSmall Offline
5
January 17, 2020 - 11:02 am
sp_Permalink sp_Print

I will have to respectfully disagree with you there Dennis. Specular reflection from one plane will cause peaks and dips in the frequency response, because all the energy will arrive with a specific time delay in respect to the source. Depending on this time delay, some frequencies will cause destructive and some will cause constructive interference, causing peaks and dips.

A properly designed and built QRD will spread that same energy out in time, this will create a more even interference-pattern. There will no longer be certain frequencies where all the reflected energy has a perfect 180deg phase shift caused by a single time delay.

Forum Timezone: America/Los_Angeles
Most Users Ever Online: 31
Currently Online:
1
Guest(s)
Currently Browsing this Page:
1 Guest(s)
Forum Stats:
Groups: 4
Forums: 10
Topics: 360
Posts: 996

 

Member Stats:
Guest Posters: 23
Members: 14403
Moderators: 0
Admins: 2
Administrators: admin, Dennis Foley
FREE ROOM ANALYSIS
Call Us 520–392–9486
100% Money Back Guarantee