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Discussion Starter #1
I have a Rockford Fosgate 351s, its 90W x2, I used it to power CDT CL-61 comps in an old car. Im considering either getting a SAX-50.4 and running it active to Pioneer TS-D720C comps, or getting TS-D720PRS comps and running them passive off the amp I already have. I heard the crossover is a weak point in both sets but the PRS is better.

I would get the SAX-100.4 but then I would have to replace all my wire with heavier gauge and Im not really up for that. This is for my own listening enjoyment so it doesnt need to be extremely loud. Its in an '05 Escape, I listen to mostly metal and rock. BTW the Pioneer sets are an upgrade from the CDTs right? I was never really happy with the midbass from the CDT's, but I also didn't have the doors sealed or deadened.
 

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I think if you aren't up to the task of running new wire, you should NOT go active! To have a good sounding active set up usually requires a lot of tweeking and tuning. I've spent a lot more time trying to tune my system than I did actually installing the equipment.

Don't feel that you MUST go active to get good sound. Passives can sound great and they are a lot easier. I like to say if you are interested in audio as a hobby, go active. If you just want a good sounding system stay passive.
 

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Discussion Starter #3 (Edited)
yeah you're prob right, thanks for the advice
 

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You know I didn't really like my CDTs either for midbass or upper end detail and like you I was ready to chuck this for another set of passive comps or go active. But after reading all the emphasis on 'install' and 'tuning' here I decided to redo my install. So more sound deadening went into the doors w/ sound absorption behind the midbass, all vibrations chased and killed, and wires rerouted to get rid of alternator whine. The tweeters in the kicks were trial and error aimed for better sound. These changes made a significant difference in the midbass impact and the detail of the sound. So if you have not deadened your doors yet do do, and take some time to tune since it will be necessary even if you eventually change out your comps.
To my ear passive works well if midbass and tweeters are close together. On the other hand active would seem nice for say tweeters in the A-pillars to raise the soundstage and the ability to mix and match parts at will. The complications will be more amp channels and a HU w/ x-overs and time alignment.
 

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active is good if you want/need the more in-depth tuning provided by the HUs or Processors supplying all those RCA's that come with them. say if your speakers were all at different positions the time alignment could solve the problem of out of phase music. but as already stated active requires more cabling and more amplifier channels, which means more money. so its really up to you if you like how it sounds then stay passive. if you think your system will benefit from the increased tuning go active. but it all depends if u got the money to spend.
 

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Virtually all home speakers still use passive xovers, including the best. There is nothing wrong with them. So unless you have a real problem install, stay with passive and forget any peer pressure to go active. If needed, just get some better passive xovers.
 

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Discussion Starter #7
Hmm I wasn't even thinking about time correction when I bought my head unit. I don't really have the cash for a processor AND an amp AND more RCAs AND speakers so it looks like the active option is off the table.
How important is it that tweeters be close to woofers in a passive setup? The only place I could see mounting them is in the sail panels or in the door panels next to the latch. I'm also looking at nice coaxials to make it even easier, maybe Morel Tempo 6c or Eclipse point source?
 

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I've run a system that had very large tweeters mounted in corner dash locations and 6.5" midranges in the front of the doors, about 1' or so from each other. That was not recommended, but seemed to work okay. They were about as far from each other as I would care to try.

If you are mounting tweeters near the rear view mirror and mids in the doors, then I would very much be concerned. Coaxials can be okay in the door, but if you can run separate tweeters nearby then do so as it is much nicer to have them up higher. Door coaxial tweeters can be difficult to tune properly, even if they have rotating mounts, as tweeters are quite directional. Any sense of realism can go right out the door, so to speak.:)
 

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Virtually all home speakers still use passive xovers, including the best. There is nothing wrong with them. So unless you have a real problem install, stay with passive and forget any peer pressure to go active. If needed, just get some better passive xovers.
You cannot compare a what works for a home theater speaker and a car audio speaker. They run passives because they know what crossover point and slopes work best for their drivers in their cabinets.
Car audio has wayy to many possible combinations of location power enclosure etc to try to have a preset crossover achieve the best results.
Active is not a bandwagon it really is a much better choice.
 

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very true. there is just too many variables to consider when installing a sound system in a car.

SkipNJ, if your tweeters are mounted in the A-pillar or otherwise in a different location to your woofers, the sound from your tweeters will arrive at your ears before the woofer, making the music sound out of phase. thats where u use time alignment to delay the tweeters to be in line with the other speakers. its also used to delay the drivers side speakers so that you hear the left and right side evenly.

at the end of the day, passive isnt bad. in fact its recommended if you need a space saving system or if youre on a budget. its really only for audiophiles who want their system to sound better. so if it sounds good as is to you, youre fine.
 

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You cannot compare a what works for a home theater speaker and a car audio speaker. They run passives because they know what crossover point and slopes work best for their drivers in their cabinets.
Car audio has wayy to many possible combinations of location power enclosure etc to try to have a preset crossover achieve the best results.
Active is not a bandwagon it really is a much better choice.
I'm sorry, but I think people put too much into what active xovers can do. For one, unless you have a really complex active xover component that can alter the xover point by really small and very accurate increments, without contributing other undue side effects, you are not going to gain much from it except for the fact that it should present no signal loss. That lack of signal loss was really the only reason they were ever introduced to car audio, and were mainly intended for subwoofers, where lack of signal loss was critical. But even if you use an active xover, and it happens to have the exact xover point your speakers require, you should probably measure the final results, as quite often these components are not 100% accurate, and even if they are there are still electrical side effects they can introduce. Someone with a little knowledge on the other hand could measure the speaker's installed response and build their own custom passive xover with a xover point that is at least as accurate if not more so, and be virtually guaranteed to have fewer side effects.
Regarding the above, how many people really know what type of quality parts are being used in the average active xover, and what influences these electrical pathways are subject to. A digital xover is even more complex and there are plenty of additional build factors that can come into play that can adversely affect sound quality. On the other hand a passive xover is exceptionally simple in comparison and often more predictable if you are using quality trusted components.
Lastly, xovers are there to simply set a high or low pass frequency cutoff point for the intended speaker, control the rate of the xover slope, and maintain phase as well as possible, not some other worldly and magical phenomenom.
So I repeat, if active xovers were that much better than passives you can bet that the home audio manufacturers would have jumped on them a long time ago. It's not like the high end home audiophiles aren't willing to spend the money on it. That’s why speaker bi-amping was more of a phase than a serious challenge to reputable system building.
Just mho.:D
 

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unless you have a really complex active xover component that can alter the xover point by really small and very accurate increments
when you are adding a sub to the system the crossover point can be very important to making the transition between the woofer and the sub seamless. being able to anjust things like the slope and the frequency point easily is a plus.

remember that just because your system is active doesnt mean its complex. a 2-way stage and sub can be quite simple, even if it is active.

But even if you use an active xover, and it happens to have the exact xover point your speakers require, you should probably measure the final results, as quite often these components are not 100% accurate
that will come down to which processor is being used

nobody is trying to say that because youre system is passive that its wrong. only that he will gain more tuning flexibility with an active system. if he really needs that and is willing to spend the extra money for it, all the better. remember not everyone needs to go active. some people are quite happy with their passive setup. in fact i would say definitely go passive if someone didnt have alot of knowledge in this area, as they could make it sound worse fiddling with an active crossover, if not damage something. active and passive both have their roles in car audio
 

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better passive xover = one tuned for your car

It's a lot easier to tune for your car with active, and that's why most here recommend it. Cars need more room correction than HT setups.
Very well said.

To answer the original question i say go ahead and buy the 4 channel sundown and run it bridged to your cdts. Head room is never bad and if you decide to go active then you already have the amp as well.
Doesnt the sundown have bandpass crossovers on it?
 

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Yes, it definitely is easier, for most people to set up their systems with active xovers, as they offer a lot of options for the buck. And I am in no way saying they are a bad idea, it's just that I think they are occasionally over rated for some scenarios. It is far too easy for newcomers to fall into the trap of assuming that active xovers are always better than passive, and that passive xovers are just a remnant of the ancient past.:)
And yes, car systems generally need a lot more work than home systems do, but not so much in the xover department. Speaker placement and their frequency and phase responses are probably by far the most critical factors in car systems. The newer time alignment devices can be a huge help in that department.
And that being said, I am quite happy with much of the progress that has been made in advanced auto sound system processing. In particular I was exceptionally pleased when Alpine teamed with Audyssey to develop Imprint, as I have been a dedicated user of Audyssey MultiEQ XT in my home system since it was first introduced several years ago. Its results can be quite spectacular, but also quite bad without a lot of experimentation. I would just like to see some further development of this system, as I think Imprint is still a little on the crude side so far, but still very promising.
 

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If you got the money and time go active. If you dont stick to passive; but keep your tweeters as close to the midrange as you can. I would even consider keeping the main mid and tweeter within 2 inches of each other. Then I would consider using a second tweeter up high with a 6 db 20khz and up tweeter. Dont be scared to play with polarity on the second set.

Going 6db @ 20 k will give you an attenuated affect.
 

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I would get the SAX-100.4 but then I would have to replace all my wire with heavier gauge and Im not really up for that. This is for my own listening enjoyment so it doesnt need to be extremely loud. Its in an '05 Escape, I listen to mostly metal and rock.
Just because a car will go 120 miles an hour [ you can drive it slower ] does not mean that you always have to floor it and go 120 mph.

The wiring will not need to be upgraded, unless it is smoking from the current running through it or it is so hot to the touch that you get first degree burns.

If you keep the volume knob down it will be fine ;) [ here are your cues that the wiring needs to be upgraded .... blown fuse,smoke, fire, etc..,

solutions .... add a second wire to help with current flow, increase voltage [pressure] , which Ohms law will show you that as pressure is increased flow or current becomes less [smaller wire can be used].
 

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Hmm I wasn't even thinking about time correction when I bought my head unit. I don't really have the cash for a processor AND an amp AND more RCAs AND speakers so it looks like the active option is off the table.
How important is it that tweeters be close to woofers in a passive setup? The only place I could see mounting them is in the sail panels or in the door panels next to the latch. I'm also looking at nice coaxials to make it even easier, maybe Morel Tempo 6c or Eclipse point source?
Sounds like you are sticking to passive. From your opening post it seems that the CDT's main fault were lack of midbass. Again, sealing and deadening your doors should be job number one regardless of what comps you will use. I like Raamat. Try the CDTs after this step and you may be surprised.
I have found that running the midbass in the doors and keeping the tweeters close by in the kicks gives the best tonal quality w/ the least hassle due to improved phase coherence and reducing the path length discrepancies from tweets to listening positions. This gives a smoother and more accurate tonal balance. Side to side imaging is good, but stage height may be limited to about dash high. To me this is not a biggie since the tonal accuracy has been much better than the door or sail panel tweeter mountings I've tried which have been mostly too shrill and side to side balance and imaging hard to get right.
Mounting simplicity of a co-axial has the downside of the midrange and tweeter info firing right into passenger/driver legs losing detail and dulling the tonal response. I've used and like that particular Rf amp for its warmish full sound and underated power. But that warmish sound really makes aiming the somewhat soft CDT tweets a must.
Now you didn't say you were running a sub stage. If not, maybe spend some of those saved funds on an amp and sub. Despite your tendency not to play 'extemely loud' a sub added onto a 'well executed' front stage can transform the systems dynamics and make for lots more fun listening. :) Goodluck.
 

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Listen to the people : deaden your doorq first (Second Skin Audio Damplifier) !!!
You will decide after that.
If you don't have any sub, buy one and a little class D amp.
Then you will see if you really need to change your front speakers.
I f you think so, buy a very good set of component speakers, and run it passive on your amp.
Listen to your system at every step.
You will see if you still want to buy a new amp to play active.

Lots of speaker brands tell to not run active with their products, because you will never be sure to have the good settings!
Enjoy your sound system my friend !!!!!
(I love mine !!!!!!!!!). :)
 

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Discussion Starter #20
Thanks everyone for the helpful advice. I did run a sub stage with the CDTs in my old car- 2 12" JBL subs in a 3cu ft sealed box off a PG X400.1. There was a terrible hole in response around 60-100hz. I plan to reuse the X400.1 with one 13ov.2 in a 1cu ft sealed box I picked up for cheap. I'll be sure to seal and deaden my doors before I try anything else.
 
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