# Live End/Dead End of Yore



## hjones4841 (Jan 21, 2009)

I remember reading a number of years ago (likely in Audio magazine) about live end/dead end room acoustic design, but I cannot remember what the whole idea was trying to accomplish. Imaging in the front and ambience in the back? This was certainly pre-multichannel (except for the "quad" of the 1970's. Remember how AWFUL that stuff was? Vinyl ticks from all 4 corners of the room. Miniscule separation. It was SQ4 and what other system?).

Anyway, someone please chime in and help me remember. Thanks.


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## eugovector (Sep 4, 2006)

You've pretty much got it.


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## ratafoin2 (Feb 20, 2007)

Hello 
A Live end Dead End control room was spread into 2 parts, the part where the speakers stands was made very dead , and the part where the producer and guest seats stood was made very lively with quadratic diffusor.
The room was very easy to work for long hours without ear fatigue.
The only trouble is that a lot of studio owner copied the concept without being very aware of the complexity of the system.
In order for this concept to work you need to have enough space (between the dead wall and the live wall) to allow for something around 20 ms totally refexion free.
This part was called the ITD or initial time delay gap
The concept was test and develop by Don Davis in the mid 70's if i am correct.
Hope this help and that my reply is not to late.


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## hjones4841 (Jan 21, 2009)

Thanks for the reply. Don Davis likely wrote the LEDE article in "Audio" magazine that I remembered, and the time frame is about right. Rather than control room, the article discussed application in home listening rooms.


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## cinema mad (Jan 28, 2007)

The live/Dead end theory is old school thinking, The new school of thought has sense evolved in to A different set of theories thus Achieving better results in room Acoustics & design ...

Cheers...


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## fredk (May 14, 2008)

Can you expand on that? 

I have seen some recommendation from Brian that _appear_ to fit into this model, such as putting lots of absorbtion on the wall behind the speakers.


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## PKinetics (Apr 22, 2009)

A true LEDE monitoring environment is more than just fuzzing up the monitor wall and putting reflective surfaces behind you. Don Davis, Chips Davis (no relation), Peter D'Antonio and Russ Berger established a whole set of criteria that encompassed the concept. Researching LEDE was made possible by Dick Heyser's then new TEF measurement system. TEF gave us the first measurements that allowed looking at time and its effects beyond just frequency and amplitude.

I don't remember all of the criteria (as I recall there were seven) and requirements but a reflection free zone (RFZ) is paramount during the early integration time (per Haas). This was established to be nominally 15 milliseconds. Effective diffusion (in the form of QRD diffusors at the time) is a requisite at the rear. And yes, the monitor soffit wall, side walls and ceiling were absorptive. Typically 4 inches or more of glass fiber behind acoustically transparent cloth.

The concept has certainly evolved over the years, but probably 90% plus of serious professional control rooms in operation reflect this design type. Some others follow the Tom Hidley and Phillip Newell "Zero Environment" philosophy (everything EXCEPT the monitor wall is highly absorptive) and a few are built following Bob Moulton's recommendations of a highly reflective monitoring environment.


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