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The experts I've read about zobel, indicate a need to keep the impedance of the woofer constant by using a zobel while passing through the response curve @ the x-over point. Otherwise the impedance curve is on an upward slope and changing with frequency therefore a specific value for x-over components can't be established.
As you said, it all depends on where you cross them over and what their impedance is at that point.
 

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Discussion Starter · #122 ·
My engineer friend asked me; Do you think a perfectly tuned amplifier needs help DOUG? :sweat:

[when we discussed adding a zobel]

:nono:
 

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I'd like to hear an EE tell us a zobel is not needed BECAUSE the rising impedance curve of a driver is inconsequential in the final analysis of the sound quality. Although the components in a zobel are cheap, I'd like to simplify x-over circuits as much as possible if a zobel does not contribute to the sound quality.
 

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Discussion Starter · #125 · (Edited)
Penguin Power

At it again....new build, although looks the same.

This is the 8" SF in a 1,400cubic inch box. I've been floundering with the tuning:

* I had a volt meter wire on the amp vs. speaker-wish I had a nickle for every time that happened........:rofl:
* The vent strips are 1/2" thickness; which I now think is working fine.

I have a few of the old Morel tweeters, they go down below 2000, so I'll give them a try. But also looking for something new.
 

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Discussion Starter · #129 · (Edited)
Crossovers - by Madisound

Links:
http://www.madisoundspeakerstore.com/approx-8-woofers/silver-flute-w20rc38-08-8-wool-cone/

http://www.madisoundspeakerstore.co...-discovery-d2606/9220-1-textile-dome-tweeter/

Just got this pair together yesterday, they are sounding very nice, well balanced, good bass, middle, highs.
Some upgraded xo parts on the way; had to double-up in few spots for now. E.g. two 3.3 caps for the 6.8 tweeter cap (one side).

However even with some of the parts miss-matched (per side), they sound very nice.

Box shown is 1375 square inches - tuned to 50-51hz

btw. 7.5oz of teased speaker wool - each.
 

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Discussion Starter · #131 ·
I think most folks would go for the bigger box, the middle is better. There's more room filling sound also.
However the 6.5's are a wow!!

Going to try two of the 6.5's in a MTM soon.
 

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Re: 6.5 vs 8 . . . . small vs big
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"There's more room filling sound " . . . . with the big
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Does that convert to, "the bigger the room" "the bigger the speakers" ?
 

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I'm okay with smaller, accurate speakers. One main reason I like these front port speakers, they are compact and sound like boxes double the size.

This last pair, I used standard grade Home Depot birch ply and they sound fine, no buzzing, ringing or boom.
Backs are 1", I glued 1/4" to the 3/4" before running though saw.

Been holding onto 2 sheets of 5/8" BB grade, next pair will be extra solid.
 

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Discussion Starter · #136 ·
Thanks Robbo, Any help with xo design is appreciated.
So 2 successful projects going on - the 8" pair sound very nice, nice bass, mid. etc.

Spent most of the day coming up with this (pic). I think most would like this idea of 2 - $29 woofers that have have really nice bass, without sacrificing tightness.
This combination of 2 - 6.5" is considered a 2.5 (I think) since I'm using a separate xo for the bottom woofer (now a 4ohm load)

I think the next build will be the "same" - but tweeter in middle (as drawn).
 

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Discussion Starter · #138 ·
now I still have the 8" penguins; some of you folks have to try the front port design :yikes:

Still mixed up on 2.5 vs. MTM. :scratch:

I thought a MTM shared the same xo and a 2.5 is two separate xo (one for the helper woofer)
 

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Still mixed up on 2.5 vs. MTM. :scratch:

I thought a MTM shared the same xo and a 2.5 is two separate xo (one for the helper woofer)
That is my understanding of it as well.
In an 8Ω MTM you need two 16Ω in parallel or two 4Ω drivers in series to get the required 8Ω.
 

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Discussion Starter · #140 ·
Okay got it, a little confusing.

Could always add a second amp (a Pseudo bi-amp).

I'd have to use a Y on each amp - which I'm sure adds a host of other issues :scratch:
 
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