I may be a bit ambitious here... but I wish to combine several successful "that's not the way it's usually done!" I've done...
...of course the goal is to have a fun one in the end that raises eyebrows.
If I can get it sorted properly.
This is actually a car audio project, for my personal vehicle.
I'm employed as a business and marketing strategy consultant in the mobile audio industry, so success and innovation here do lend me credibility in that respect as well!
Now, look past that this is for a car - I'm not in need of a car audio advice - I'm in the need of passive crossover advice.
Here's the situation:
One 1995 Nissan Pathfinder. Manual transmission.
One previous in-car line-array project... and "line array" is really a misnomer - project goals were to phase-align a series of drivers to simulate a single driver located further away.
Since then, I've been pondering how much better it could be if using speakers that are more full-range speakers, rather than a traditional component set -
So, to that end, I will be using:
(6) Tang Band W3-871S full-range speakers (three per door)
(4) Peerless 830341 5.25" for midbass duty (two per door)
(1) prototype 12" subwoofer (4 ohm final impedance)
and possibly only if they prove necessary:
(2) [undecided] small tweeters for A-pillars
I've got a fantastic amp to power all this with:
(1) Alpine MRV-1507 - rated 150x2 @ 4 ohms, and is 2 ohm stable.
I'd like to run the subwoofer from 75hz and down (I'd go lower, but for practical reasons won't have a crossover slope any steeper than 12dB/octave).
I'd like to run the midbass from 75hz up to only 250hz... and this is the crux of my dilemma.
I'd like to run the W3-871S's from 250hz up to 15Khz - or heck, maybe just let them run all the way up. The goal is to make these speakers play virtually everything...
...but I thought maybe I'd be able to milk a tad bit more detail if I ran "real" tweets from 15k and up - and the Xover point would be so high as to hopefully virtually not cause any issues.
Here's the issue:
I'm rather new to three-way crossover designs - but I know at a high level, they recommend that you leave a minimum of three octaves of spread between the two crossover frequencies, to avoid acoustical anomolies.
75 to 250hz is not even two octaves.
The goal, of course, is to maximize the performance of the line array - and that means letting them play as many frequenicies as possible.
It won't be possible to locate my midbass drivers anywhere nearly as ideal - so in the same respect, I want to absolutely minimize what they are playing, because there will be fundamental imaging issues - I'm already worried about needing to let them play up as far as 250hz, but it's a necessary evil since the W3-871S mids only can reach so far down.
Part of me is saying "screw it - just build the 3-way crossover, and employ an L-pad to at least take care of any midbass exaggeration".
...the logic being that acoustical anomolies in the 75hz-250hz range won't be as likely to cause sound quality issues (and wouldn't occur as often, anyway) as higher frequency ranges would.
But part of me wants to pose the question to see what other people think of this dilemma.
Any thoughts on either:
1) am I right in thinking that in this frequency range, anomolies will be minimized / won't be as noticable?
2) any means of contending with them, or designing a crossover specifically for such a narrow passband?
Thanks in advance!
...of course the goal is to have a fun one in the end that raises eyebrows.
If I can get it sorted properly.
This is actually a car audio project, for my personal vehicle.
I'm employed as a business and marketing strategy consultant in the mobile audio industry, so success and innovation here do lend me credibility in that respect as well!
Now, look past that this is for a car - I'm not in need of a car audio advice - I'm in the need of passive crossover advice.
Here's the situation:
One 1995 Nissan Pathfinder. Manual transmission.
One previous in-car line-array project... and "line array" is really a misnomer - project goals were to phase-align a series of drivers to simulate a single driver located further away.
Since then, I've been pondering how much better it could be if using speakers that are more full-range speakers, rather than a traditional component set -
So, to that end, I will be using:
(6) Tang Band W3-871S full-range speakers (three per door)
(4) Peerless 830341 5.25" for midbass duty (two per door)
(1) prototype 12" subwoofer (4 ohm final impedance)
and possibly only if they prove necessary:
(2) [undecided] small tweeters for A-pillars
I've got a fantastic amp to power all this with:
(1) Alpine MRV-1507 - rated 150x2 @ 4 ohms, and is 2 ohm stable.
I'd like to run the subwoofer from 75hz and down (I'd go lower, but for practical reasons won't have a crossover slope any steeper than 12dB/octave).
I'd like to run the midbass from 75hz up to only 250hz... and this is the crux of my dilemma.
I'd like to run the W3-871S's from 250hz up to 15Khz - or heck, maybe just let them run all the way up. The goal is to make these speakers play virtually everything...
...but I thought maybe I'd be able to milk a tad bit more detail if I ran "real" tweets from 15k and up - and the Xover point would be so high as to hopefully virtually not cause any issues.
Here's the issue:
I'm rather new to three-way crossover designs - but I know at a high level, they recommend that you leave a minimum of three octaves of spread between the two crossover frequencies, to avoid acoustical anomolies.
75 to 250hz is not even two octaves.
The goal, of course, is to maximize the performance of the line array - and that means letting them play as many frequenicies as possible.
It won't be possible to locate my midbass drivers anywhere nearly as ideal - so in the same respect, I want to absolutely minimize what they are playing, because there will be fundamental imaging issues - I'm already worried about needing to let them play up as far as 250hz, but it's a necessary evil since the W3-871S mids only can reach so far down.
Part of me is saying "screw it - just build the 3-way crossover, and employ an L-pad to at least take care of any midbass exaggeration".
...the logic being that acoustical anomolies in the 75hz-250hz range won't be as likely to cause sound quality issues (and wouldn't occur as often, anyway) as higher frequency ranges would.
But part of me wants to pose the question to see what other people think of this dilemma.
Any thoughts on either:
1) am I right in thinking that in this frequency range, anomolies will be minimized / won't be as noticable?
2) any means of contending with them, or designing a crossover specifically for such a narrow passband?
Thanks in advance!
...and on a related note, with regard to the tweeters:
If I decide to use a set of tweeters, with a 15Khz Xover point as I mentioned:
I'm assuming that since my next lowest Xover point is 250hz below that one (about six octaves) that I should be able to get away just fine with building a standard 2-way crossover for them?
Or in other words...
A 3-way Xover design to handle the sub, midbass, and mids...
With the issues I mentioned originally.
And then just a 2-way crossover design to handle the mid to tweet handoff...
...since there will be six full octaves between midbass/mid and mid/tweet.
That's the plan - I'm hoping it'll work - I'm pretty well stuck with it due to the other numerous variables of the overall plan - but this Xover design is really the glue bonding it all together - so any help is greatly appreciated!
If I decide to use a set of tweeters, with a 15Khz Xover point as I mentioned:
I'm assuming that since my next lowest Xover point is 250hz below that one (about six octaves) that I should be able to get away just fine with building a standard 2-way crossover for them?
Or in other words...
A 3-way Xover design to handle the sub, midbass, and mids...
With the issues I mentioned originally.
And then just a 2-way crossover design to handle the mid to tweet handoff...
...since there will be six full octaves between midbass/mid and mid/tweet.
That's the plan - I'm hoping it'll work - I'm pretty well stuck with it due to the other numerous variables of the overall plan - but this Xover design is really the glue bonding it all together - so any help is greatly appreciated!
Yes, I have, since that's really traditionally how it's always done in car audio (and that's one reason I'm intentionally not ), but I'm not going to for several reasons:
1) remember the scope of the project - to combine several other "that's not the way it's usually done" concepts into one project. Particularly with the trend in car audio to go "all active" [including ditching supplied passives sold with high-end component sets]. One goal is to showcase that going passive is an option, since it's rarely done.
2) I currently have in my posession one single car audio amplifer that I can dedicate to this particular vehicle. It happens to be a tremendously expensive amplifier, Alpine's highest end 2-channel model - it's more than capable of powering even 2 0hm loads across the entire frequency spectrum (I'd only be touching 2 ohms in the midbass range, though).
3) It would be prohibitively expensive to abandon the single amp that I already have now, and purchase 3-4 other amps, of similar quality. I would also, in that case, wish to purchase an actual active crossover unit (and one that could handle all the channels I wish), as opposed to trying to coordinate each amp's discrete HP and LP filter to one another. An expensive proposition all around.
4) This single amplifier is physically massive (28" long) - given the scope of use of my Pathfinder, I'm actually going through some pretty extensive fabrication just to have somewhere to mount this one amplifier (and a bit more to make it look nice ) - finding somewhere to mount multiple amplifiers isn't even possible, again due to the scope of use for my Pathfinder...
I'm truthfully squeezed for space even on where the passives are going - they'll have to be hidden behind panels - not easy!
Fundamentally though, in the scope of my professional position - I want to be able to demo something that simply opens eyes - in my position, all too often I see customers who aren't able to see that there are, in reality, multiple options before them - that they don't need to do something the same way everyone else does:
Going active instead of passive is "the way everyone else does it".
Going with a traditional component set rather than this phase-aligned line-array would likewise be "the way everyone else does it".
Just like it's traditionally simply argued that "more speakers = worse" by those that don't understand that the issues that make that statement generally true (you won't find me arguing against it as a generalization!) actually can be mitigated...
...it is also traditionally [in car audio circles] regarded that "active > passive".
I want to help people question what they might have simply accepted as a generalization in their minds in the past.
But, of course, if there's all kinds of 75hz-250hz funkiness - I don't want to inadvertantly reenforce that generalization.
It's really to put an underscore and an exclaimation point on the end of something that's built to raise eyebrows, if that helps.
...AND - in the event that there is funkiness - I do have a 1/3 octave dual-mono Phoenix Gold equalizer that I could employ (although I'd hate to find somewhere to install it - and I'd also love to additionally show that "you don't need EQ to sound good" - but in an install this complex, I'm trying to keep my expectations realistic), if necessary.
Sorry for all the words...
), but I'm not going to for several reasons:1) remember the scope of the project - to combine several other "that's not the way it's usually done" concepts into one project. Particularly with the trend in car audio to go "all active" [including ditching supplied passives sold with high-end component sets]. One goal is to showcase that going passive is an option, since it's rarely done.
2) I currently have in my posession one single car audio amplifer that I can dedicate to this particular vehicle. It happens to be a tremendously expensive amplifier, Alpine's highest end 2-channel model - it's more than capable of powering even 2 0hm loads across the entire frequency spectrum (I'd only be touching 2 ohms in the midbass range, though).
3) It would be prohibitively expensive to abandon the single amp that I already have now, and purchase 3-4 other amps, of similar quality. I would also, in that case, wish to purchase an actual active crossover unit (and one that could handle all the channels I wish), as opposed to trying to coordinate each amp's discrete HP and LP filter to one another. An expensive proposition all around.
4) This single amplifier is physically massive (28" long) - given the scope of use of my Pathfinder, I'm actually going through some pretty extensive fabrication just to have somewhere to mount this one amplifier (and a bit more to make it look nice
) - finding somewhere to mount multiple amplifiers isn't even possible, again due to the scope of use for my Pathfinder... I'm truthfully squeezed for space even on where the passives are going - they'll have to be hidden behind panels - not easy!
Fundamentally though, in the scope of my professional position - I want to be able to demo something that simply opens eyes - in my position, all too often I see customers who aren't able to see that there are, in reality, multiple options before them - that they don't need to do something the same way everyone else does:
Going active instead of passive is "the way everyone else does it".
Going with a traditional component set rather than this phase-aligned line-array would likewise be "the way everyone else does it".
Just like it's traditionally simply argued that "more speakers = worse" by those that don't understand that the issues that make that statement generally true (you won't find me arguing against it as a generalization!) actually can be mitigated...
...it is also traditionally [in car audio circles] regarded that "active > passive".
I want to help people question what they might have simply accepted as a generalization in their minds in the past.
But, of course, if there's all kinds of 75hz-250hz funkiness - I don't want to inadvertantly reenforce that generalization.
It's really to put an underscore and an exclaimation point on the end of something that's built to raise eyebrows, if that helps.
...AND - in the event that there is funkiness - I do have a 1/3 octave dual-mono Phoenix Gold equalizer that I could employ (although I'd hate to find somewhere to install it - and I'd also love to additionally show that "you don't need EQ to sound good" - but in an install this complex, I'm trying to keep my expectations realistic), if necessary.
Sorry for all the words...
Your idea can be achieved, a few years ago I custom made a 4 way passive x-over for a comp system (also with a big 2ch alpine amp), subs to 80hz, midbass 80-200, mid 200-5k, tweet 5k up, had good results with it.
You'll need a very large inductor for the sub, both wire size and iron core size (or you'll saturate it at high volume)
You'll need a very large inductor for the sub, both wire size and iron core size (or you'll saturate it at high volume)
Finally had a few minutes to get back to this project (it's killing me driving around with a pair of 8-year old Alpine coax's that I pulled into substitution duty until I get myself rolling here...
)...
Here's the inductor that I was planning on using:
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=266-958
...an 18mH, 16 gauge inductor, that they've rated for use up to 500w.
I'm using an Alpine amp rated at 150x2 RMS... or 600w bridged (as I'll be running it to my sub).
While I'd technically be exceeding the 500w rating here - I'm operating the sub in a car, and that's one hell of a lot of power - I won't be needing it all. In fact, the components I'm using are collectively rated at about 60w.
In other words... I'd likely never be operating the amp so that it would be putting even 400w through this inductor.
(and in the same vein of thought... I'm not terribly concerned about power burned up across ESR... I've got power in excess - this is a huge amp, and I don't need huge)
But the little devil on my OTHER shoulder is whispering "what if?" into my ear...
So let's say that I modified my design a bit to accomodate a 'full power' situation...
...In that case, couldn't I run four of these inductors in series/parallel (in absence of having two 36mH inductors available to parallel ) to bring me well beyond the 600w mark?
(I'm not too worried about magnetic interference... I can work around that, as I'm locating the Xover componentry into chassis cavities - which are plentiful, in the car. I could even locate the inductors more than a foot apart from each other.)
Or, my thoughts more directly:
What single inductor are you picturing, that would be so large, so expensive, and so heavy?
)...Here's the inductor that I was planning on using:
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=266-958
...an 18mH, 16 gauge inductor, that they've rated for use up to 500w.
I'm using an Alpine amp rated at 150x2 RMS... or 600w bridged (as I'll be running it to my sub).
While I'd technically be exceeding the 500w rating here - I'm operating the sub in a car, and that's one hell of a lot of power - I won't be needing it all. In fact, the components I'm using are collectively rated at about 60w.
In other words... I'd likely never be operating the amp so that it would be putting even 400w through this inductor.
(and in the same vein of thought... I'm not terribly concerned about power burned up across ESR... I've got power in excess - this is a huge amp, and I don't need huge)
But the little devil on my OTHER shoulder is whispering "what if?" into my ear...
So let's say that I modified my design a bit to accomodate a 'full power' situation...
...In that case, couldn't I run four of these inductors in series/parallel (in absence of having two 36mH inductors available to parallel
) to bring me well beyond the 600w mark?(I'm not too worried about magnetic interference... I can work around that, as I'm locating the Xover componentry into chassis cavities - which are plentiful, in the car. I could even locate the inductors more than a foot apart from each other.)
Or, my thoughts more directly:
What single inductor are you picturing, that would be so large, so expensive, and so heavy?
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