Pioneer CS-77 Crossover mod update

Hi To All,
I wanted to give an update on my Pioneer CS-77 crossover mods that Steve Ponsford (aka. system7) suggested awhile back. I have attached a photo of the completed work. Try not to laugh to hard, this was my first time soldering on this level. Everything turned out great. My test album Dire Straits Brothers in Arms sounded very good. Bass is much improved and overall sound is much more detailed compared to the original crossover! This is an awesome forum with very helpful members. A special thanks to Steve for sharing his superior knowledge of crossover design with me.
 

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Hi montana1,
Make sure everything is stuck down securely. Don't trust glue / hot glue / silicone for everything. You do need those things to kill rattles though. RTV silicone might be your best bet, the high temperature kind judging from the look of the top right coil.

-Chris
 
Rich, I'm proud of you!

Pioneer CS-77

523485d1452165204-pioneer-cs-77-speaker-mod-suggestions-pioneer-cs-77.jpg


Pioneer CS-77

523412d1452112468-pioneer-cs-77-speaker-mod-suggestions-pioneer-cs77.jpg


I proposed improving the bass rolloff with second-order 4.7mH coil and 3.3R plus 22uF shunt.

Add a 1R/15R attenuator to the mid and wire it negative polarity. The rest is unchanged. See how it sounds.

Like SO, except we changed the 33uF to a 22uF IIRC:

523413d1452112468-pioneer-cs-77-speaker-mod-suggestions-pioneer-cs-77-changes.png


How does it sound? Is it balanced? I was a bit worried I might have gone overly bassy...but you can adjust things. :cool:
 
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Steve,
Great to hear from you! I'm very pleased with the sound. It certainly is not overly bassy. I'm thinking of further adjustments down the road consisting of a baffle change/ redesign. Something like the Seas 503 kit. That is why only cheap caps were used at this time. I have started 'The Core' two way build from Paul Carmody and once completed; I will re-visit the Pioneer baffle idea. What I really need is to acquire some testing equipment.
Brick, by brick....as the saying goes

Best Regards,
Rich
 
There's nothing wrong with using a cheapie NP electrolytic in a bass shunt with a resistor of 3.3R. See any marginal ESR of around 1 ohm just gets lost.

TBH, I don't believe in overly expensive components. Tiny differences. :)

529489d1454725089-pioneer-cs-77-crossover-mod-update-img_0164.jpg


TBH, I didn't want to mention it, but I'm slightly concerned you may have placed the attenuator in front of the LC mid filter rather than after it, thus subjecting it to bass energy. But it probably won't blow up. Sturdy 10W resistors. :D
 
Steve,
I could be wrong but I believe the attenuator is after the mid coil. I looked at schematic probably a 100 times (or close to it. lol) . If its incorrect its not to late to change. But, I came off positive tag on right side of photo with 12 uf cap, then through .33 mh coil, attached 1 ohm resistor running to positive tab for mid speaker and ran 15 ohm resistor lead to ground tab. Wired the mid neg at speaker itself. Does all that sound correct?

Thanks,
Rich
 
Rich, I'm proud of you!

Pioneer CS-77

523485d1452165204-pioneer-cs-77-speaker-mod-suggestions-pioneer-cs-77.jpg




Like SO, except we changed the 33uF to a 22uF IIRC:

523413d1452112468-pioneer-cs-77-speaker-mod-suggestions-pioneer-cs-77-changes.png


How does it sound? Is it balanced? I was a bit worried I might have gone overly bassy...but you can adjust things. :cool:
Hello system 7. That diagram you drew of the crossover is a new design for the cs 77s correct? Is that something I can show parts Express and they would be able to send me all the correct pieces to build? Also is the crossover built just like you have in the diagram just attach this wire to this section and so forth? I've never built a crossover so yeah I'm definitely lost :)
 
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Hi Steve,
Great advice, and I agree with you in every way! It also agrees with my experience over decades of doing things like this.

Hi Lojzek,
I'm sorry, but I can't agree with your statement. Not even close. Drivers can be pretty individual in how they respond and sound. They aren't perfect pistons and have resonances and other departures from perfection. They also require different internal volumes and you can't correct for that in a crossover.

Commercial boxes are almost always too small and too light for the driver. This is because of one indisputable fact, when you ship a speaker, you are shipping a heavy box of air. Because the shipping cost figures in the list price, manufacturers and distributors will design a box to be as small and light as they can get away with. The worst tended to be store brand speakers and smaller packed systems, but even some very expensive systems suffer from the same economic pressure. It is worthwhile to note that one practice was to ship the drivers and crossovers to the target market where the box would be made and system finished off more locally. That was a good compromise. This is one reason why DIY systems using better drivers could easily outperform a commercially available product. I designed several systems for the business I worked at early in my career, and at the nest place too. This would have been from about 1979 to 1988, and I learned a lot about speaker system design.

Too bad that these days, DIY anything is not common. However, excellent vendors like Solen in Montreal, Canada can provide really good drivers and crossover components. They can even design crossovers and enclosures for you. I highly recommend dealing with a vendor like Solen. I have dealt with them since probably the mid to late 80's and the staff is excellent.

-Chris