Parker 98's in 8ohm - what is the easiest way to drop the tweet 2.5db? - diyAudio
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Old 1st May 2012, 03:15 AM   #1
JZatopa is offline JZatopa  United States
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Default Parker 98's in 8ohm - what is the easiest way to drop the tweet 2.5db?

So I am rewiring my parker audio 98's to be 8 ohm loads. For those of you that are not familiar with the speakers, they are an MTM arrangement. The two 4 ohm 93db/w/m woofers are run as wideband drivers without crossovers. A FT17 covers the top with a simple 2uF cap making a first order crossover. When they are wired for 2 ohms, the tweet matches the woofers without any padding. Now that I have the drivers wired in series, the tweet is about 2.5db more efficient then the woofers. Using an l-pad calc it looks like I need a 2ohm in series and a 24 ohm resister in parallel. Considering how simple this setup is, can I just use a 2.7 ohm resistor in series and call it a day?
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Old 1st May 2012, 04:07 PM   #2
JZatopa is offline JZatopa  United States
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Am i on the right track?
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Old 1st May 2012, 04:27 PM   #3
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Consider that the 24 Ω parallel acts also as impedance peak flattening
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Old 1st May 2012, 04:59 PM   #4
JZatopa is offline JZatopa  United States
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The graph here http://www.madisound.com/loudspeaker...ions/ft17h.pdf doesn't show much of a peak. Still worth putting the shunt in?

How important is the quality of the shunt transistor? can I use sand cast or should I get something better?
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Old 1st May 2012, 05:10 PM   #5
AllenB is offline AllenB  Australia
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It won't be possible to get an identical response to the original whether you use a single series resistor, a standard L-pad or if you were to go with a lower value of shunt resistor for the flattest impedance although there shouldn't be much in it. You should probably try the standard L-pad and assume you'll need to tweak it from there, unless you want to take it to measurements.

The sand cast resistors should be fine.
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Old 1st May 2012, 05:58 PM   #6
JZatopa is offline JZatopa  United States
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Would ARTA + and ECM8000 be good enough for measurement?
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Old 1st May 2012, 08:10 PM   #7
AllenB is offline AllenB  Australia
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I would think so.
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