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Discussion Starter · #1 ·
Just finished the latest re-work of my sub(s). Three 10’s in a sealed (common chamber) box with .73 cu/sub).

303933


I debated between 2 ported and 3 sealed and basically decided on 3 sealed because 1. I like the looks of it and 2. You know, “sound quality” 🤷🏻‍♂️ (I know, I know).

Was showing it to a friend that does this stuff and he said “Have you considered just making the center one a passive radiator? You’d get some of the benefits of ported but the looks you want.” 🤔

The answer - “No, never considered that.”

I don’t know the first thing about passives. I did enough reading to know I’d need to remove the magnet from it to work as a passive. No clue how to tune it. The only passive radiator I’ve ever had was on a factory Kicker box in 1987 and it used a foam type radiator.

Honestly it is PLENTY loud enough for me as it is and plays low enough. But I’m always wondering “what if” and don’t mind tinkering.

Really just a rambling thought in my head since he mentioned it - but figured it was worth throwing out there.

Any thoughts/ideas/comments/ridicule?
 

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First let me say your install is very clean and well done! Nice! Leave it alone!!! I don't know the answer but do you think 2 subs and one passive will be louder or deeper than your current setup? I'll follow with interest as some of the knowledgeable chime in...
 
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Discussion Starter · #3 ·
First let me say your install is very clean and well done! Nice! Leave it alone!!! I don't know the answer but do you think 2 subs and one passive will be louder or deeper than your current setup?
Thanks! The answer to your question is “I have no idea”. Two subs PORTED (properly tuned) could/should play lower (to a point) and a bit louder - but I don’t know if passives act similarly.

Doing some reading it sounds like just using 1 as a passive would end up hitting excursion limits with 2 powered subs. (I think?). I’d go disconnect the center one just for grins to see what it sounds like if I wasn’t worried about destroying it and not being able to go back. I found a couple of people on old threads that use passives but they are purpose built - not an re-purposed sub.

You are probably right - I should just leave well enough alone.

PS - laughing at your signature line! 🤣
 
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Discussion Starter · #5 ·
Generally you run more cone area in passive radiators vs subs, so you would run one sub and two radiators if all were 10”, or a 10” sub with a 12” passive radiator for example
That’s kinda what I was thinking. Makes sense I guess. I guess the radiator would have to be VERY stiff/heavy if you had 2 subs/1 radiator - and then what’s the point?

That said, the old Kicker box I had 30+ years ago had 2 8’s and a single 10” (estimated) radiator - but who knows what what going on with that thing (or maybe it was two 6 1/2’s and a radiator...man that was a long time ago...)

Thanks
 

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Just finished the latest re-work of my sub(s). Three 10’s in a sealed (common chamber) box with .73 cu/sub).

View attachment 303933

I debated between 2 ported and 3 sealed and basically decided on 3 sealed because 1. I like the looks of it and 2. You know, “sound quality” (I know, I know).

Was showing it to a friend that does this stuff and he said “Have you considered just making the center one a passive radiator? You’d get some of the benefits of ported but the looks you want.”

The answer - “No, never considered that.”

I don’t know the first thing about passives. I did enough reading to know I’d need to remove the magnet from it to work as a passive. No clue how to tune it. The only passive radiator I’ve ever had was on a factory Kicker box in 1987 and it used a foam type radiator.

Honestly it is PLENTY loud enough for me as it is and plays low enough. But I’m always wondering “what if” and don’t mind tinkering.

Really just a rambling thought in my head since he mentioned it - but figured it was worth throwing out there.

Any thoughts/ideas/comments/ridicule?
I'm with @DaveG, leave it alone. OR, give them enough power to reach near Xmax. SQ-wise, ported boxes and passive radiator boxes add a large amount of group delay, bandpass boxes add even more, the only thing better than sealed is infinite baffle.
 
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  • I would leave it alone if it is sounding good.
  • The Earthquake SLAPS 10M could work if the 2 subs are not high excursion.
  • Ideally one would have a DSP that could equalise phase and address group delay.
 
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Your setup is great how it is. Ported adds group delay but is more efficient. You know what also adds efficiency? More cone area which you already have.

Since you have alot of cone area your subs will be moving less, so less distortion. Your setup looks perfect just the way it is. I personally run two 12's sealed... one almost does the trick but i like the second for the higher efficiency, lower distortion from them moving less and most of all.. the abiliity to crank it up even louder with the extra punch in the trunk and no need to worry about bottoming them out. Sometimes when i was running a single 12 i would occasionally bottom it out.
 

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Discussion Starter · #10 ·
Well that’s enough votes for “leave it alone” for me. I don’t want to crater a sub playing around. Thanks for all of the input.

Guess I’ll divert my time and attention to putting a sub in my wife’s car instead - she’s been on me to do that for quite some time.
 
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Oh, I forgot to mention... you generally do need two similarly sized passive radiators for one single sub in most applications like @dumdum mentioned (double the cone area) so yeah... I wouldn't touch it
The SLAPS "M" have 3-4" of Xmax, so you only need 1 with a high excursion sub... maybe 1 would work with 2 low excursion subs?

They have T/S specs, so one could model it and know beforehand.

But not touching it, is a good option.
 

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Discussion Starter · #12 ·
The SLAPS "M" have 3-4" of Xmax, so you only need 1 with a high excursion sub... maybe 1 would work with 2 low excursion subs?

They have T/S specs, so one could model it and know beforehand.

But not touching it, is a good option.
303950


Interesting. For $80 it might be worth a shot just to see what I think - unfortunately it looks like it requires a cutout about 3/8” bigger than I currently have and would thus be a commitment to cut it bigger.
 

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Well that’s enough votes for “leave it alone” for me. I don’t want to crater a sub playing around. Thanks for all of the input.

Guess I’ll divert my time and attention to putting a sub in my wife’s car instead - she’s been on me to do that for quite some time.
Maybe use a PR for the Haus Frau's car?
 
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Discussion Starter · #15 ·
Happy wife...happy life
Yep. She’s got an Infinity QX80 with the Bose system. It actually sounds pretty good for a factory stereo but no bottom end at all. I’m just planning to tag a LOC off of the anemic 6 1/2” factory “sub” speaker wires. Bought her a Rockford T500-1 amp and I’ll build a box with a single 10” sub that can sit in the rear corner. It’ll be removable (I’ll put handles on it for her) in case she wants it out if she wants to cram stuff back there.

She should be happy with adding some bump to her factory Bose... I think 🤔...hopefully I’m not igniting a fuse that ends up costing me thousands in a custom install for her car! 🤣
 
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304043

This is my first passive setup and I was blown away by the sound , it's kinda different in that it creates more vibrations , like if you have your home subwoofer directly behind your seat , you can feel it as well as hear it , it vibrates the whole car , it goes very low but also has very good punch and is extremely clean sounding low distortion bass.

Yes correct you need double the volume in the passives per active driver , this is where the Dayton audio passive drivers are very good in that they have double the cone travel that there active counterparts have so you can have 1 same size passive as your active driver . The above is 2 x RSS265HO-4 and 2 x RSS265-PR , one passive is in the middle and the other one directly opposite on the other side.
 

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First off, that is a really clean build.
Now just from a personal standpoint, I’ve never heard a sealed setup I was happy with. I’ve built 3 of them, and none of them stayed in my vehicle for more than a few weeks.
The passive radiator setup I’m running now is, to my ears, the best sounding setup I’ve ever built, out of about 30 enclosures I have built, although it’s not the loudest.
So, I think PR’s are great, however, I would almost never recommend for someone to “convert” an existing build into a PR build. If you wanted to try a PR setup, I’d say research them, and do a PR build from scratch,
Also, be aware that a correctly built PR setup needs to have double the volume displacement of your sub(s) so typically, one 10” sub, would need two 10” PR’s…. But you don’t have to keep with the same sizes. You might be able to run one 15” PR with two 10” subs.
I made the mistake of running two 15” PR’s with one 18” sub, but my PR’s are actually maxed out, and they have had some damage to them because of it.
Also you should know, that PR’s will cost you a couple DB’s in loudness.
304047
 

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Discussion Starter · #18 ·
Well dang, just when I had made up my mind to just leave it alone. lol 🤔

I’m intrigued. It’s something I’ve never done before and I’m always wanting to change things up/build new stuff. I’m very happy with how my current set-up sounds as well as how it looks - but I’m sure I’ll get bored and want a project down the road so I’ll definitely keep the idea of passives in the back of my mind.

Thanks to everyone for the input!
 

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Discussion Starter · #19 ·
View attachment 304043
This is my first passive setup and I was blown away by the sound , it's kinda different in that it creates more vibrations , like if you have your home subwoofer directly behind your seat , you can feel it as well as hear it , it vibrates the whole car , it goes very low but also has very good punch and is extremely clean sounding low distortion bass.

Yes correct you need double the volume in the passives per active driver , this is where the Dayton audio passive drivers are very good in that they have double the cone travel that there active counterparts have so you can have 1 same size passive as your active driver . The above is 2 x RSS265HO-4 and 2 x RSS265-PR , one passive is in the middle and the other one directly opposite on the other side.
Ya know, I think I remember seeing that pic of your set-up in a different thread a while back. At the time I hadn’t given any thought to passives and I wasn’t paying much attention. At the time I thought you had 2 drivers and 1 passive - didn’t realize there was another passive on the other side of the box. Makes sense.
 
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