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Tempest AA SPL's Do I need a BFD???


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#1 of 5 Bill**H

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Posted April 18 2004 - 07:50 AM

I just got my Tempest AA up and running last night. I watched Matrix Revolutions as the first movie, (I've been saving it just for this). I can say it kills my 2 Sony SA-WM40's down low! I set it up 5 dB hot and my room is 2900 cubic feet. Volume was set to -10dB and I sit 13 feet away from the Sub and speakers. The Tempest spit out a little bit of Polyfil from the ports sometime during the movie.

I ran some test tones today and here is what I got. I started at 75 dB @ 16 Hz but found out the center was also on so I unhooked it and got 73.25dB and just left the volume set where it was for the rest of the test. The SPL's are with just the Sub running. Receiver @ -11 dB.

Hz------SPL------corrected (is this right??)
16------73.25------84.75
18------79.5-------87.5
20------82---------89.5
22------86---------92.5
25------88.5-------93.5
28------92.5-------96.5
31.5----93---------96
36------95.5-------98
40------94.3-------97
45------95---------97
50------99.5-------101
56------95.5-------97
63------90.5-------92
71------95.5-------97
80------88---------89.5
89------84.5-------86
100-----82---------84
111-----83.75------84.75
125-----65---------65.5
142.5---64---------64.5


I had my crossover set to 80 and only the Sub running. The room has some vibrations, I don't know how that plays with the meter readings I got. I did fix 2 of them but, didn't take time to find the others. I was afraid I would burn the voice coil up???

The Tempest doesn't seem to have the impact in the mid freq. that the Sony's had, but it shakes the floor and rattles the marble in the coffee table like the Sony's never did!

So, Do I need a BFD????

Bill

#2 of 5 GrahamT

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Posted April 18 2004 - 09:08 AM

I think you should get a BFD. You have a hump centered at 50 Hz and a BFD will knock it down no problem.

Like you I had two Sony m500s and wanted to go lower so I built an EBS Tempest. I also had a hump around 40-50 and got a BFD to knock it down and it made a HUGE difference. I think it is fun to play with the BFD filters and I made a house curve so the lower frequencies are boosted.

#3 of 5 GrahamT

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Posted April 18 2004 - 09:10 AM

Here is a page on how to use the BFD. It really isnt as complicated as it first appears and it is very helpful.

http://www.snapbug.ws/bfd.htm

#4 of 5 Bill**H

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Posted April 19 2004 - 01:49 PM

Graham,

Do you have the SPL numbers for before and after the BFD was put in line? How much boost did you put and where? The Tempest is "Bad to the Bone", I just want it to hit me in the chest some more like others here have said their's do.

Bill

#5 of 5 GrahamT

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Posted April 19 2004 - 02:04 PM

I just did a new house curve tonight. The readings were taken at the listening position. It slopes from 20 to 80 with a null at 75 Hz but it changes if I move the meter slightly. These numbers are RS corrected but I dont think I can post the charts so here are the numbers:

Hz----- Baseline --- w BFD (3 filters)
16.8---85.7---90.7
17.8---86.7---93.7
18.8---85.7---96.7
20-----88.5---99.5
21.1---88-----98
22.4---88.3---95.3
23.7---89.7---93.7
25.1---89.0---92.0
26.6---89.5---90.5
28.2---92.0---93.0
29.9---93.5---93.5
31.6---94.0---93.0
33.5---94.9---92.9
35.5---96.8---92.8
37.6---97.6---91.6
39.8---98.5---91.5
42.2---99.3---91.3
44.7---98.0---91.0
47.3---98.8---90.8
50.1---97.5---88.5
53.1---94.5---87.5
56.2---92.5---87.5
59.6---86.5---85.5
63.1---86.5---85.5
66.8---82.5---83.5
70.8---81.5---82.5
75-----75.5---74.5
79.4---80.5---77.5
84.1---82.6---82.6
89.1---84.7---84.7
94.4---85.9---85.9
100----82.0---82.0

If you copy these numbers into a spreadsheet (excel) and chart them it will be easier to see. You have to get used to the deep clean bass of the Tempest. Unfortunately for me I have a hump in the 35-50 Hz range and I have no choice in placement so the BFD was a must.




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