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Multi-Way Conventional loudspeakers with crossovers

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Old 30th April 2012, 04:14 PM   #51
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In term of level, the two drivers (SDS134 and Vifa 1TC9FD18-08) are very similar. In term of response on the baffle, diffraction, the response could be very different because the vifa have less directivity in high frequency. The Vifa is a better driver in the midrange.
You can use my crossover with your drivers (Vifa and Hiquphon). This crossover is "enough versatile".

In my latest evolution, I pay attention to the impedance. This 3 ways impedance curve is very similar to the Manzanita's.
See John's measurement :
Fast, fun, Inexpensive OB project
Note the minimum impedance is near 50Hz and its value is not below 7ohms.

Add a second woofer divides the impedance by two and diminishes the distortion.

You don't bother me with your questions

Regards.
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Old 30th April 2012, 04:39 PM   #52
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Great! I'll follow up in a couple of weeks or so and let you know how I proceed.
Kindest,
Mark
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Old 1st May 2012, 09:17 PM   #53
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OK
Just a note Mark,
If you use the HIQUPHON OW I, 8 ohms, 87dB, the value of the LPAD R5/R6 on the tweeter should be as a starting point : R5=3.3ohms and R6 = 3.9ohms (+2/-1 ohms, to be tune).
The other HIQUPHON tweeters : 8ohms/90dB , don't change anything. Could be need tuning too, but you have the starting point.
Regards.
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Old 2nd May 2012, 04:20 PM   #54
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Jerome,
Thank you for the heads up with the Hiquphon.
Have decided on an initial direction, couldn’t wait two weeks, here’s what’s up. I built a set of prototypes using your baffle and the components from my Manzi prototypes… have a lot of unfinished and finished wood lying around. Also went ahead with cut outs for a second set woofers. I’m going to order another set of woofers, run the Vifa’s and incorporate a single set of Hiquphon’s. (Might like to try a different mid down the road, you’d mentioned “A version with a better midrange using the 5" glass-fibre cone 830991”).
I blanked off the holes with tape and cardboard and gave them a listen…sounded pretty good… looking forward to improvements with an updated x-over and added tweeters.
Based on this direction do I stay with the x-over in your post #49 or was that just for the single woofer version? Also, do your comments from post #24 still apply?
Thank you,
Marko
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Old 2nd May 2012, 06:16 PM   #55
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Hi Marko,

You are as impatient as me

I understand you are going to make an order and you want to have all the parts ?
If you add a second woofer, you have to change the crossover because the second woofer changes a lot of things. The sensitivity of the loudspeaker increases by ~6dB, changes also a little the crossover (see below).

The woofer crossover have changed. The inductor is now 10mH, keep the DC resistance below 0.4ohms. The network Lz1/Cz1 changes. The network Rz2/Lz2/Cz2 is optional but buy a 1000uF electrolytic bipolar cap, and a 10ohms (10W min) resistor and listen. It suppresses a bump near 50Hz and extends the low end response, and improves the phase impedance.
The LPAD on the mid and tweeter have changed too...
If OWI tweeter, then R5=1ohms and R6=10ohms. No change if other OW.

Have Fun
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Old 2nd May 2012, 07:31 PM   #56
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Thanks for the clarifications.

Ya, we can be driven sometimes...our greatest strengths can sometimes be our greatest weaknesses.

Here's a pic of the prototype very much in need of additional drivers.
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File Type: jpg Big OB prototype 001.jpg (296.9 KB, 443 views)
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Old 2nd May 2012, 07:59 PM   #57
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Cool
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Old 3rd May 2012, 11:04 PM   #58
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Jerome, have you ever worked with this driver?
Gorlich Podzsus TT-130
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Old 4th May 2012, 06:04 AM   #59
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No i have never worked with this driver. I google it, it an expolinear.
Audio Chassis Berlin | Expolinear

I would like not to work with this driver for a lot of reasons.
The TS parameters are not very easy to work with,
Qt=0.22 Fs=30Hz vas =29L... Not easy to do a BR box, a closed box and passive open baffle. Perhaps a TL Line ?
The price is high 285 ~ 375$ I'm extremely wary with drivers at such high price... I prefer build a multiway with cheaper drivers.

Note i found very interesting links
About the SDS 134 it is interesting to see numerous speakers with various price.
Here: ASE - Acoustic Systems Engineering 134 a kit
A commercial speaker Gemme Tonic G3 : 500
Goldmund metis : ensemble hifi non class GOLDMUND METIS 24190.00

Note a kit with the vifa 19TD... : ASE - Acoustic Systems Engineering
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Old 5th May 2012, 04:16 PM   #60
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Jerome - Thanks for sharing your project and all that you have learned along the way. I recently completed a pair of Manzanitas and am enjoying them very much. I would like to fill in the mids a bit though and your low cost version looks promising. I am happy with the bass on the manzi's so your latest cross over looks good with the 20 mH inductor. I have a couple questions though:

This first one is a little embarrassing. When you list an inductor as 470.00 uF, that would be a .47 mH ?

I could not find the Scan Speak replacement for the Vifa but I found this tweet and it looks like it has the right properties to function well with your x-over; http://www.madisoundspeakerstore.com/sb-acoustics-soft-dome-tweeters/sb-acoustics-sb26stcn-c000-4-tweeter-4-ohms/ The off axis response looks very good and the price at $34 is appealing too.

Hope you are having a pleasant spring in France.
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