JD1000/1 and impedance rise question!!

[zoltman1991]

Hi there.

Got my system clamped.
JD1000/1 pushing a 12" CompQ DVC4 wired to 2ohms.

My JD1000/1 is 1000w rms at 2ohm stable. No stability at one ohm.

Clamp reveals 537w at 4.0Xohms.

Since this is contingent off of the box, cabin, car, etc, CAN I replace my DVC4 with a DVC2 to wire it to 1ohm, knowing that it will see a 2x rise and effectively be at 2ohm so the amp can push out it's full 1000w? Would this still be stable for the amp?

Another alternative is switching amps(and likely sub too), but I'd rather just switch out one component if I can.

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[metalheadjoe 10+ year member]

Amps are rated for impedance. Expect problems if you wire it below rating.

 

[zoltman1991]

Amps are rated for impedance. Expect problems if you wire it below rating.

Yes, but my amp will see the 2ohm load after the rise. That's my question. Your answer was a bit vague regarding amp's stability. How does impedance rise play into this?

 

[Jimi77 5,000+ posts]

Yes, but my amp will see the 2ohm load after the rise. That's my question. Your answer was a big vague regarding amp's stability. How does impedance rise play into this?

Impedance rise doesn't play into this. Was it pink noise or a burp/frequency where you got the 4 ohm reading? I suspect you'll be tripping the protect circuit at anything above 6/10 listening levels. You can always try it out and see how it goes.

 

[zoltman1991]

Impedance rise doesn't play into this. Was it pink noise or a burp/frequency where you got the 4 ohm reading? I suspect you'll be tripping the protect circuit at anything above 6/10 listening levels. You can always try it out and see how it goes.

I was playing music. Used different songs as representative samples. Notes hit from 33hz to 51hz. Clamped at each song. Roughly 4ohm reads with 500w or so.

 

[Doxquzme Premium Member]

Even if you could, little difference between 500 and 1000 watts, like 10-15% (real world) in the car. Not worth the risk to the amplifier.

 

[Jimi77 5,000+ posts]

I was playing music. Used different songs as representative samples. Notes hit from 33hz to 51hz. Clamped at each song. Roughly 4ohm reads with 500w or so.

How were you measuring impedance? Voltage dividing network?

 

[zoltman1991]

How were you measuring impedance? Voltage dividing network?

We had a device that measured it!

BHG-WM - Wattmeter

- Measure True Amplifier Power output - Measure Phase Difference between Voltage and Current into reactive loads (PF) - Measure AC Volts- Measure AC Current - Measure Max Amplifier capabilities with PEAK mode.

bassheadgarage.com

 

[zoltman1991]

Even if you could, little difference between 500 and 1000 watts, like 10-15% (real world) in the car. Not worth the risk to the amplifier.

Can you elaborate? Are you suggesting that 500w into a 12" v 1000w into a 12" wouldn't be a significant enough change? Seems fairly considerable. It's the Kicker CompQ, and I'd like to see what it can do at the full 1000w

 

[Jimi77 5,000+ posts]

Can you elaborate? Are you suggesting that 500w into a 12" v 1000w into a 12" wouldn't be a significant enough change? Seems fairly considerable. It's the Kicker CompQ, and I'd like to see what it can do at the full 1000w

3db max and I guarantee it'll be less than that. I'd try measuring power/impedance with a test tone

 

[Doxquzme Premium Member]

Can you elaborate? Are you suggesting that 500w into a 12" v 1000w into a 12" wouldn't be a significant enough change? Seems fairly considerable. It's the Kicker CompQ, and I'd like to see what it can do at the full 1000w

In a silent sound room with no noise, 3 db (roughly 33%). In a car, about 10-15% Theoretical doubling of the sound to the ear requires more than an 8:1 ratio of power to realize a doubling of the volume to the ear. The math actually reads like this.
The ear perceives a doubling of the volume at roughly 9-10 db. Starting with a base line at 500 watts of input power, the math looks like this:
500 to 1000 watts, you get a 3 db gain or a 33% increase in volume.
1000 to 2000 watts, another 3 db gain or a 66% increase in volume
2000 to 4000 watts, another 3 db gain or a 99% increase, a doubling of the volume to the ear. That is a 8:1 ratio, in a perfectly quiet chamber with a mic placed 1 meter from the speaker.
So whether it’s the same wattage to a speaker that is 3 db more efficient or the same efficiency with increased power, the math applies either way. In a car environment, it will be much less that these results obtained in an sound testing room. Therefore, expect maybe a 15% difference all things being equal.

 

[zoltman1991]

In a silent sound room with no noise, 3 db (roughly 33%). In a car, about 10-15% Theoretical doubling of the sound to the ear requires more than an 8:1 ratio of power to realize a doubling of the volume to the ear. The math actually reads like this.
The ear perceives a doubling of the volume at roughly 9-10 db. Starting with a base line at 500 watts of input power, the math looks like this:
500 to 1000 watts, you get a 3 db gain or a 33% increase in volume.
1000 to 2000 watts, another 3 db gain or a 66% increase in volume
2000 to 4000 watts, another 3 db gain or a 99% increase, a doubling of the volume to the ear. That is a 8:1 ratio, in a perfectly quiet chamber with a mic placed 1 meter from the speaker.
So whether it’s the same wattage to a speaker that is 3 db more efficient or the same efficiency with increased power, the math applies either way. In a car environment, it will be much less that these results obtained in an sound testing room. Therefore, expect maybe a 15% difference all things being equal.

Veryyyyy interesting! Thank you for that.

So basically, if it can be done, the results would be there (not impressively apparent, but still there).
If not able to be done, I could likely switch to a larger amp that outputs more at 4ohms. Again, would still see the results (not as I would initially would have thought), but would still be there.

That being said, let's say the JD1000/1 idea is a no go.
Would let's say a Kicker CXA1800.1 (1800 at 2/800 at 4) be a viable option?
-No risk to delivering the full 1800 to my sub, right? As long as I provide clean signals, subwoofer should be safe, as it will see the rise and read a 4ohm load?

What I'm gaining is that... if I want to chase every bit of power (as you say 10-15% increase), I can either;
-get another subwoofer to wire it lower, so that the impedance rise would be 2x from 1ohm, so amp would deliver more at 2ohm. OR get a higher rated amp that outputs more at 4ohm.

 

[Doxquzme Premium Member]

Veryyyyy interesting! Thank you for that.

So basically, if it can be done, the results would be there (not impressively apparent, but still there).
If not able to be done, I could likely switch to a larger amp that outputs more at 4ohms. Again, would still see the results (not as I would initially would have thought), but would still be there.

That being said, let's say the JD1000/1 idea is a no go.
Would let's say a Kicker CXA1800.1 (1800 at 2/800 at 4) be a viable option?
-No risk to delivering the full 1800 to my sub, right? As long as I provide clean signals, subwoofer should be safe, as it will see the rise and read a 4ohm load?

What I'm gaining is that... if I want to chase every bit of power (as you say 10-15% increase), I can either;
-get another subwoofer to wire it lower, so that the impedance rise would be 2x from 1ohm, so amp would deliver more at 2ohm. OR get a higher rated amp that outputs more at 4ohm.

Yes, if you can give it 3 times the power it is getting now, it will be about 30% to 40% louder. You can't really predict the effect of rise (accurately to my knowledge) and honestly, it can't be overcome so not sure what the fixation is, I mean I get it, but kinda don;t at the same time. it's a rabbit hole for which there is no return....

 

[zoltman1991]

Yes, if you can give it 3 times the power it is getting now, it will be about 30% to 40% louder. You can't really predict the effect of rise (accurately to my knowledge) and honestly, it can't be overcome so not sure what the fixation is, I meran I get it, but kinda don;t at the same time. it's a rabbit hole for which there is no return....

I mean three times would be well over my subwoofer's rated RMS handling.
Now off topic question.. I had this conversation with someone earlier.

He suggests that if I put 500w into a 500w sub, it'll sound louder than if I put 500w into a 1000w sub?

I kinda smell a lot of BS here. 500w into a sub is 500w into a sub. Shouldn't make a difference what the sub is rated at right? Seems absolutely incorrect.

 

[Doxquzme Premium Member]

There

I mean three times would be well over my subwoofer's rated RMS handling.
Now off topic question.. I had this conversation with someone earlier.

He suggests that if I put 500w into a 500w sub, it'll sound louder than if I put 500w into a 1000w sub?

I kinda smell a lot of BS here. 500w into a sub is 500w into a sub. Shouldn't make a difference what the sub is rated at right? Seems absolutely incorrect.

I think your sub has a thermal limit of 850 watts RMS. I usually recommend no more than 50% over the RMS for the amp, not so that you can toast it, but to account for dynamics mostly. As to the other discussion, not sure what the content of that discussion was, but on its face, that doesn't sound correct. There are a number of factors that contribute to volume, not just power. Efficiency at rated can be substantially different. He may have been talking in terms of generally accepted observations that lower powered speakers are often more efficient. There is math for all of this too. It's gets progressively more expensive and difficult to increase power and efficiency both which ultimately will net the greatest output, all other things being equal.

 

[Doxquzme Premium Member]

Put one of these in a 1.5 cu ft box, tuned to 30-33 hz, give it 1000 watts, sit back and enjoy! https://stereointegrity.com/product/sql-12-series-2/ -------------- Here is the perfect box.
33hz

Box External Dimensions Width x Height x Depth	24.00" x 13.00" x 16.92"
Material Thickness	0.75"
Net Internal Volume	1.50 ft3
Tuning Frequency	33 Hz
Port Area	24.00 inch2
Port Inlet Width x Height	2.09" x 11.50"
Port Length	33.57"

Example (not the actual box)

 

[Jimi77 5,000+ posts]

If you're chasing db's the best solution is more cone area.

 

[1point21gigawatts]

Hi there.

Got my system clamped.
JD1000/1 pushing a 12" CompQ DVC4 wired to 2ohms.

My JD1000/1 is 1000w rms at 2ohm stable. No stability at one ohm.

Clamp reveals 537w at 4.0Xohms.

Since this is contingent off of the box, cabin, car, etc, CAN I replace my DVC4 with a DVC2 to wire it to 1ohm, knowing that it will see a 2x rise and effectively be at 2ohm so the amp can push out it's full 1000w? Would this still be stable for the amp?

Another alternative is switching amps(and likely sub too), but I'd rather just switch out one component if I can.

You are good where you are at. The only thing that you can do is build a better box. Clean up ground too. 2x rise is normal.

 

[1point21gigawatts]

Put one of these in a 1.5 cu ft box, tuned to 30-33 hz, give it 1000 watts, sit back and enjoy! https://stereointegrity.com/product/sql-12-series-2/ -------------- Here is the perfect box.
33hz

Box External Dimensions Width x Height x Depth	24.00" x 13.00" x 16.92"
Material Thickness	0.75"
Net Internal Volume	1.50 ft3
Tuning Frequency	33 Hz
Port Area	24.00 inch2
Port Inlet Width x Height	2.09" x 11.50"
Port Length	33.57"

Example (not the actual box)


View attachment 61286

Good specs, wrong design. Kudos. Hold up.
Port specs- 3”x8”, 14” port length.
Box specs. 9.5” height, 16” width, 14” depth.
Sub up/port back.

 

[1point21gigawatts]