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Old 3rd March 2013, 06:37 PM   #91
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Quote:
Originally Posted by RonVinyl View Post
Maybe a zobel network is not needed because the baffle width is only 12.5 inches. (Still absorbing as much information as possible, really a noob at this right now)

If this is the case, then we should only need a simple resistor and inductor for the BSC.

Rparallel = Re x (10^db/20 -1)
Rparallel = 5.7 x (10^3/20 -1)
Rparallel = 5.7 x (10^0.15 -1)
Rparallel = 5.7 x 0.413
Rparallel = 5.7 x 0.413
Rparallel = 2.3541

Rparallel = 2.5 Ohms (Parts-Express)

f3 = 4560/Wb
f3 = 4560/12.5"
f3 = 364.8 Hz

Lbsc = Rparallel/(2 * Pi * f3)
Lbsc = 2.3541/(2 * Pi * 364.8)
Lbsc = 2.3541/2292.106
Lbsc = 1.0 mH

Lbsc = 1.0 mH (Parts-Express)
This is whats needed for a 3db attenuation. Probably a better bet for this speaker design with the front port.
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Old 3rd March 2013, 06:57 PM   #92
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I agree 6db may be too much. Certainly a 1 mh coil is a lot less cash.
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Old 4th March 2013, 04:43 PM   #93
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So, I had an idea. If I were to purchase an L-pad, is it possible to use this in place of the resistor for adjustable attenuation? Usually when I have played with the calculators the attenuation is changed by changing the inductor and resistor. Can it be changed by only adjusting the resistor?
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Old 4th March 2013, 07:46 PM   #94
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I think the inductor controls the freq cut-on of the bsc and the resistor the level of correction - need inductor still.
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Old 4th March 2013, 08:14 PM   #95
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I know an inductor is still needed. But the inductor value, for example, changes between the 3db attenuation circuit and the 6db attenuation for the WiBAQ. Why would it change if its the resistor that dictates the level of attenuation and the inductor controls the frequency?
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Old 4th March 2013, 09:17 PM   #96
xrk971 is online now xrk971  United States
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The R & L values are not truly independent but to first order the L controls freq range and the R controls the level of attenuation of the higher frequency range. You can read more about it here, but it basically says that you can adjust the R independently if you feel you have cut the HF too much that it feels lifeless, or if you feel bass is too weak then you need to increase R. So an L pad should work as long it has the approximate range of R's you need.




From mh-audio.nl - Home

"1. Adjust the value of Rbsc
a) If the bass is still too weak, then the amount of attenuation is too little. The value of Rparallel should be increased until the bass seems to be balanced with the rest of the SPL spectrum.
b) If the speaker sounds dull and lifeless, the value of Rparalllel is too high. Reduce the value of Rparallel to bring life back into the music.
c) Continue adjusting Rparallel until the speakers sound right to your ears. It is probably best to use acoustic music as a reference during this adjustment period.
d) To remove the effect of the baffle step correction circuit completely, substitute a piece of speaker wire for Rparallel.

2. Adjust the value of Lbsc
a) Depending on the final value of Rparallel, the original calculated value of LBSC might need to be changed slightly. This sets the frequency range over which the baffle step filter attenuates the midrange and high frequencies. If the mid bass sounds depressed, then a lower value of LBSC should be used. I typically perform this adjustment last once I am satisfied with the balance, between the very low bass and the midrange, I have achieved with the resistor.
b) Decreasing the value of LBSC will tend to warm the sound of the speaker if the previous value produced a depressed mid bass response.
c) Always round down to the next available inductor size, having too low of an inductor value is a lot less problematic then having too large of an inductor value."
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Old 4th March 2013, 09:22 PM   #97
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Hey thanks. Sounds pretty good then.
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Old 6th March 2013, 10:23 AM   #98
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I have been meaning to do this just didn't get around to it yet. Here are some pics of the final pair of speakers as they are set up in my room, in case anyone wants to see

the placement is not ideal but its the best I can do for now.
Attached Images
File Type: jpg AIMG_0817.jpg (982.9 KB, 795 views)
File Type: jpg AIMG_0823.jpg (984.2 KB, 297 views)

Last edited by Dumbledog; 6th March 2013 at 10:32 AM.
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Old 6th March 2013, 03:26 PM   #99
xrk971 is online now xrk971  United States
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Nice looking speakers Nice medals and ribbons too - what are they for?
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Old 6th March 2013, 05:59 PM   #100
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Swimming. Our high school team is one of the best in the state. Those are personal medals and ribbons from championship meets. Just finished my senior season about 20 days ago
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