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In the Forum: Horn-Loaded Speakers
In the Thread: 45Hz Bass Horn
Post Subject: You use wrong criteria.Posted by Romy the Cat on: 6/19/2008

Jessie,

Unfortunately it is in my view it is absolutely imposable to predict anything juts based upon the CAD modeling. The entire criteria that you for founding the right positioning of your instantiation are wrong, at least in my view. You use the consideration of time arrival, esthetics, light of sight, localization… Do not get me wrong – they are very important criteria but there are even more essentials criteria – something that overrides everything and something that will dictate to you how and where your installation will be organized. Truest me, you will not have a lot of chooses if you will be using the right criteria. From there you will use the rules of time arrival, esthetics, light of sight, localization etc but it will be in a given framework, the only framework that your room will dictate.

In my view you will hit two major aspects, answer to which will dictate how to position your playback. The very first will be something that I described in the “About speakers Imbedded Macro-Positioning” article:

http://www.romythecat.com/Forums/ShowPost.aspx?postID=4421#4421

Fist: The midbass big horns would have over 10dB difference between being imbedded in the room hot spot and placed somewhere else. In the “hot spot” the midbass horns will load the room in a manner that shell make to stop even thinking about other location for the channel.  Everything else will just flow from the only positioning of the midbass horns.

Second: the LF channel. In your room you need to measure what your LF channels outputs. You might position them between the midbass the MF horns tower of your might put then outside of the midbass – you never know. If you cross then at 30Hz-40Hz for instance than in one spot it might more or less evenly load the room, in another spot it will have plus or minus 12dB somewhere. If you do then it is imposable to cure anything besides just moving the woofers 3-5 meters away to a completely different location.  Usually sane size rooms have those bass suck outs and influxes at 50Hz -100Hz – you with your hypothetical 30Hz-40Hz crossover will be beyond this level. Still the woofers might hit you with problems with their tail response. Do not take out of consideration the opportunity for lower bass channel to work TOGETHER with midbass horn. You might accomplish it by crossing the woofers at 100Hz for instance. Let patent that your naked woofers have 95dB flat from 200Hz to 50Hz and then at the bottom then have in a given location a huge boom of plus 12dB from 50Hz to 25Hz. Why to fight with it if you can use it: you might declare the 107dB of the sub 50Hz and the woofer new reference sensitivity, crossing the woofers at 100Hz and letting the woofers to run 12dB behind the midbass.

The point I am trying to make is that the actual measurement of the footers, midbass and partially the upperbass will dictate where to position the system. When you found the strategic positioning then you can go for tactical positioning. For instance the MF island will “read” the proximity to the back wall and you will curves the leading edge of imaging accordingly – you will play with those details lately…

Anyhow, I do not think that an abstract CAD modeling might say anything indicative. I have somewhere else in my site somebody was asking about the specific positioning of speakers and I was very none-cooperative. It was not an accident and not my desire to be a jerk. The proposer positioning is an ability of the system owner to assess the results and to react to outcome. I think having any precompiled concepts in this is not a good idea. I am sure, you Jessie, will find the way how to load you room with speakers. In the end do not forget the following:

http://www.romythecat.com/Forums/ShowPost.aspx?PostID=2553

The caT

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