Higher impedance and lower power vs lower impedance higher power

[Jonnyswboy]

Will a sub rising higher perform the same mechanically on lower power as a speaker with less rise on higher power?

In other words, will a more efficient box be quieter than a less efficient box with more power?

I believe I would have to upgrade my amp to give my subs rated power due to rise.

Nsv5 12s at 0.5 ohm are rising to about 2.5-3.5 ohms on a salt 8. So I would only be getting around 2000-2500w per sub.

Wishing I went with a B2 Riot 16k full bridge as it has >200 damping factor. But I'm stuck at half ohm now so my only upgrade path is a BC17k.

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[Popwarhomie 5,000+ posts]

Plenty of full bridge amps that are .5 ohm stable.

 

[Jonnyswboy]

Plenty of full bridge amps that are .5 ohm stable.

All I know of is the Taramps 12k. If there's one with good damping factor under $1800 I'd be interested. I'll have to look around.

 

[Popwarhomie 5,000+ posts]

All the Taramps Bass lines are .5 ohm stable.

Bass 15k
MD 12k
Would be my two choices.

I’m on my phone right so so I’m not going to try and look up dampening factors.

 

[Buck 5,000+ posts]

Seal it off first.

 

[Buck 5,000+ posts]

Anything that changes pressurization and cone movement will or easily can affect impedance. If you want to do a low impedance box, you're going to sacrifice musical quality, almost certainly. I would run more power. Those subs will take all of the power. I wouldn't run them in a smaller box.

Bro, I'm telling you, put them on like 5k a piece. The X's, Z's, and NS's, they all appear to shine through on higher the RMS power levels, very honestly. You literally have the most badass sub Sundown makes; those subs will take monster power.

Chasing rise is like chasing a dragon, if you want do music, to some extent. I genuinely think you should keep everything that you have, get all that you have 100% sealed off and finished, and see what that does first. I'm afraid you'll change something too early, before you seal off or something like that, or run at full power. You need to have the structure of the car completely finished, seal it off, and then measure impedance again, IMO.

Any changes near the face of the box or major changes to cabin airspace will affect impedance. Any change to pressure levels around the face of the box, that will change how the sub moves. Sealing it off is going to bring higher pressure around the face of the box, and it should limit the cone travel due to more in-box pressure, depends on frequency, and that should change impedance, not sure what hz or to what extent, but it should some.

 

[Buck 5,000+ posts]

Like seriously, I would just keep everything as is, get it fully finished structurally, and I mean fully. Don't half do it in anticipation of changing it. You need to fully do it so you can realistically know the next best move. I don't want to encourage over-spending or anything like that, as far as the power goes. I'm just saying to get the best overall performance, you need to do isolated step by step changes, and see what all of those changes do. You know? You've got a custom box, your car that has it's sound character, and your system is not going to be the same as anyone else's, really. So you gotta learn your system as much as possible; that will really help you know what to do.

You might get it sealed off, see the impedance, and be like "Oh, I see this now, now I wonder what happens if I do this....", and that's how greatness starts.

 

[Jonnyswboy]

Like seriously, I would just keep everything as is, get it fully finished structurally, and I mean fully. Don't half do it in anticipation of changing it. You need to fully do it so you can realistically know the next best move. I don't want to encourage over-spending or anything like that, as far as the power goes. I'm just saying to get the best overall performance, you need to do isolated step by step changes, and see what all of those changes do. You know? You've got a custom box, your car that has it's sound character, and your system is not going to be the same as anyone else's, really. So you gotta learn your system as much as possible; that will really help you know what to do.

You might get it sealed off, see the impedance, and be like "Oh, I see this now, now I wonder what happens if I do this....", and that's how greatness starts.

Wow, I wish I found this video earlier. This is the best explanation of rise.

So if my changes drop me 0.5-0.75 ohms I will have the perfect box! Can't wait to get to testing. If I am unable to lower it I will have good bandwidth and thermal headroom which isn't bad either. Now I understand why damping factor is so important in musical boxes!

 

[Buck 5,000+ posts]

Wow, I wish I found this video earlier. This is the best explanation of rise.

So if my changes drop me 0.5-0.75 ohms I will have the perfect box! Can't wait to get to testing. If I am unable to lower it I will have good bandwidth and thermal headroom which isn't bad either. Now I understand why damping factor is so important in musical boxes!

 

[hispls 5,000+ posts]

Nsv5 12s at 0.5 ohm are rising to about 2.5-3.5 ohms

You do realize that impedance changes with frequency, right? What precisely are you trying to accomplish here?

 

[Jonnyswboy]

You do realize that impedance changes with frequency, right? What precisely are you trying to accomplish here?

I am aware. I want my impedance (at least at tuning frequency) to at least be low enough to allow my amp to deliver rated power to the subs. I want to hit mechanical and thermal limits roughly at the same time. Still need to do more testing.

 

[hispls 5,000+ posts]

I want my impedance (at least at tuning frequency) to at least be low enough to allow my amp to deliver rated power to the subs.

If you are only going to be playing one frequency you need to tighten up absolutely everything else and be very certain that is the frequency you want to use, from there you figure out where your impedance is at that frequency and either change amps or coils and test to see if your amp stays out of protect long enough for your burp. You may be able to roll into it if you wind up right on the edge of what the amp will drive.

As Buck mentioned any of those changes you make to the box or sealing the cabin will change your peak frequency and your impedance curve as will opening door/window so if you want to play the low impedance game make sure every other variable is exactly where you will using it in the lanes, then figure out coils/amp(s) with testing and be very careful if you change literally anything else (including the frequency you burp) after that.