Trying to decide which subwoofer to get

[hispls 5,000+ posts]

Yep I had 4 Sa 18s on a crossfire 8k which does like 10-11k at 1ohm. So I sent them 2.5k each, according to hispl. And when I took them out and sold them the coils were mint!

Are you being purposefully obtuse just for the sake of argument or do you genuinely not know how impedance works?

 

[Massive spl]

30seconds over 3k per woofer and this ain't nothing, he plays daily like this. Has the low voltage and blown amps to prove it lmao! But the woofers with 3" coils. Never burned a single coil

 

[Massive spl]

Are you being purposefully obtuse just for the sake of argument or do you genuinely not know how impedance works?

I was purposely making fun of you there^ u must have not caught on

 

[adulbrich 5,000+ posts]

He mentions impedance when it's convenient for him to argue.

If you say you're giving your amp a certain amount of power, he'll say it's less than that because of rise.

If you say you're using a big amp but the subs are seeing less power, he'll say that your amps are seeing way more than is safe.

If you clamp a certain amount, he'll find another way to argue.

 

[hispls 5,000+ posts]

So my 20k could have been sending 20k to my subs because I never mapped the impedance?
Clean power is an unclipped sine wave

Yes impedance varies with frequency

I suspect if your amp was making close to 20KW you would have killed those subs very quickly so probably not. More likely you played them hard right around tuning and the amp saw 6 or 8 ohms most of the time. That does NOT mean that if you find your z-min frequency you couldn't have smoked those subs in under 30 seconds of hard play if you chose the wrong song.

What is it about that extra 30% more power from "clipped signal" that would push things over the top? This implies that 1200W square wave isn't the exact same power as 1800W sine wave? You're going to need to go a long way to show the math to prove that when it's commonly accepted that average (RMS) power = .707 * peak.

Much like "box rise", "clipping" is some mythical boogeyman that people use to explain just about anything they don't understand.

 

[Massive spl]

I find it funny that around me and my group of friends no one has ever burned a sundown coil. They only thing that ever burned up was two tinsel leads from yardsale woofers before the XL leads were standard on them.

Set up one 2 zv4 12s on a twisted 8.5k... No problems

Set up two 4 nsv3 18s on two crossfire 8ks.. No problems

Set up three 4 zv4 15s on two ab 750.1... No problems

Set up four 4 nsv3 15s on two ab 750.1 16v... No problems...

If 3" coils couldn't handle the power how are these daily system not having coil failure? Not even once?

 

[trumpet 5,000+ posts]

Much like "box rise", "clipping" is some mythical boogeyman that people use to explain just about anything they don't understand.

Add to the list "must be a phase issue".

 

[adulbrich 5,000+ posts]

I suspect if your amp was making close to 20KW you would have killed those subs very quickly so probably not. More likely you played them hard right around tuning and the amp saw 6 or 8 ohms most of the time. That does NOT mean that if you find your z-min frequency you couldn't have smoked those subs in under 30 seconds of hard play if you chose the wrong song.
What is it about that extra 30% more power from "clipped signal" that would push things over the top? This implies that 1200W square wave isn't the exact same power as 1800W sine wave? You're going to need to go a long way to show the math to prove that when it's commonly accepted that average (RMS) power = .707 * peak.

Much like "box rise", "clipping" is some mythical boogeyman that people use to explain just about anything they don't understand.

How do you know that without mapping my box impedance? How can you assume that about someone else's equipment that you don't own and have never heard?

Seriously? A square wave causes it to see full power longer at the peaks and it isn't moving at the time to cool itself.

 

[trumpet 5,000+ posts]

A square wave causes it to see full power longer at the peaks and it isn't moving at the time to cool itself.

A squared off bass tone is still alternating, and at 30 Hz that cone is moving 30 times a second.

 

[wew lad 5,000+ posts]

Would it be fair to say that running a frequency sweep and finding the minimum impedence would represent z-min?

Is this accurate enough to prevent too low impedence on an amp

 

[hispls 5,000+ posts]

I know for a fact your subs weren't getting full power for long because you didn't burn up the coils.

You really don't understand how AC works do you? 1200W square wave = 1800W sine wave period end of story.

If you're implying that the cone isn't making the same number of strokes per second (to cool itself) with a square wave vs. a perfectly rounded sine wave you definitely need to visit an autism specialist.

Draw a graph with a zero line, a +1200 line and a +1800 line and a -1200 and -1800 line. Now draw a sine wave 1800 + and - peaks and shade in the area between 0 line and the waveform. That is your RMS average power. You can do the math (peak X .707), use graphing software, or just count the shaded squares of your graph paper to verify.

Now draw a perfect square wave (likely never going to happen real-world) with 1200 + and 1200- peaks and shade in the area. You will find that it is the same (I'm using 1200 and 1800 for simple rounding but it should be close enough to illustrate th

e point).

 

[Massive spl]

That video is terrible quality, what number is he even averaging?


The point is YOU DON'T KNOW. Are you autistic or are you just arguing for the sake of upping your post count and seeming clever?

Here's a plot of an IA DP 15" in a box in a friend's trunk. Sub was D1 ohm in series

Freq Z Phase

15.102 2.683 41.555

15.545 2.726 39.454

16.000 2.978 42.368

16.469 2.978 42.368

16.951 2.849 44.178

17.448 3.233 44.698

17.959 3.311 50.796

18.486 3.311 50.796

19.027 3.166 42.159

19.585 3.786 47.957

20.159 4.161 45.887

20.749 4.677 48.693

21.357 5.061 50.550

21.983 5.929 48.592

22.627 6.063 53.765

23.290 7.393 50.971

23.973 8.700 39.470

24.675 10.001 23.034

25.398 10.632 13.574

26.143 10.724 -6.893

26.909 10.601 -19.937

27.697 10.476 -19.372

28.509 9.654 -0.399

29.344 7.767 9.765

30.204 6.430 12.347

31.089 5.282 19.261

32.000 4.590 -9.399

32.938 4.942 0.464

33.903 4.085 7.621

34.896 4.091 31.757

35.919 4.417 33.120

36.971 4.728 21.600

38.055 6.431 19.223

39.170 11.710 17.052

40.317 14.000 24.871

41.499 15.474 34.245

42.715 15.290 40.030

43.967 9.676 53.901

45.255 5.998 41.863

46.581 6.504 42.828

47.946 8.219 24.102

49.351 8.919 6.982

50.797 10.070 -0.993

52.285 10.004 1.794

53.817 9.224 -22.105

55.394 8.248 -26.781

57.018 6.400 -38.902

58.688 6.975 -24.881

60.408 6.151 -20.460

62.178 5.594 -15.973

64.000 4.529 -10.567

65.875 3.700 -9.065

67.806 3.224 -5.173

69.792 2.928 -0.442

71.838 2.871 5.384

73.943 2.895 9.608

76.109 2.965 12.382

78.339 3.013 15.430

80.635 3.055 18.042

82.998 3.099 20.603

85.430 3.155 22.714

87.933 3.174 23.872

90.510 3.209 24.674

93.162 3.282 26.269

95.892 3.464 28.820

98.701 3.567 30.323

Can you not fathom how a "8KW" @ 2 ohm amp for example could be "all day err' day" to this sub while at the same time if you found a song that played some of these frequencies hard you could blow the sub up in a hurry?

Those big Sundown coils are 3" 8 layer. General rule of thumb used by loudspeaker engineers is 100W X coil diameter (in inches) X layers. That's continuous power. Your friends probably know what they're doing, play songs with high impedance when they're showing off, and are smart enough to turn it down if they smell something funny.

Using this sort of anecdotal evidence to recommend some rookie runs an amp at half ohm or runs double rated power to a woofer is irresponsible.

I know for a fact your subs weren't getting full power for long because you didn't burn up the coils.

You really don't understand how AC works do you? 1200W square wave = 1800W sine wave period end of story.

If you're implying that the cone isn't making the same number of strokes per second (to cool itself) with a square wave vs. a perfectly rounded sine wave you definitely need to visit an autism specialist.

Draw a graph with a zero line, a +1200 line and a +1800 line and a -1200 and -1800 line. Now draw a sine wave 1800 + and - peaks and shade in the area between 0 line and the waveform. That is your RMS average power. You can do the math (peak X .707), use graphing software, or just count the shaded squares of your graph paper to verify.

Now draw a perfect square wave (likely never going to happen real-world) with 1200 + and 1200- peaks and shade in the area. You will find that it is the same (I'm using 1200 and 1800 for simple rounding but it should be close enough to illustrate th

e point).

Yea not sure why that video came out crap. But averaging like 158-159db on non boosted music

 

[hispls 5,000+ posts]

Would it be fair to say that running a frequency sweep and finding the minimum impedence would represent z-min?
Is this accurate enough to prevent too low impedence on an amp

The proper tool for the job is Dayton DATS. 100$ at Parts Express and worth every penny. But yes, that's what you'd want to do to be safe.... assuming of course that the amp manufacturer didn't already gamble (cough Brazilians cough) that you'd run their rated impedance nominal sub and that within normal bandwidth you're not already coming in a bit high.

In the example I posted, if you could cross over with a steep enough slope you could probably get away with 24-64hz running this "2 ohm" woofer with a 4 ohm stable amp. It may go into protect though even at low power when it sees the lower impedance though. If you were using test tones you could be 100% confident of what's going to happen or if you mixed your own music or had a good spectrum analyzer you could chose songs that didn't have anything outside the "safe" areas and be fine as well.

 

[adulbrich 5,000+ posts]

A squared off bass tone is still alternating, and at 30 Hz that cone is moving 30 times a second.

Still moving 30 times per second, but it's seeing more peak power without more movement

That video is terrible quality, what number is he even averaging?


The point is YOU DON'T KNOW. Are you autistic or are you just arguing for the sake of upping your post count and seeming clever?

Here's a plot of an IA DP 15" in a box in a friend's trunk. Sub was D1 ohm in series

Freq Z Phase

15.102 2.683 41.555

15.545 2.726 39.454

16.000 2.978 42.368

16.469 2.978 42.368

16.951 2.849 44.178

17.448 3.233 44.698

17.959 3.311 50.796

18.486 3.311 50.796

19.027 3.166 42.159

19.585 3.786 47.957

20.159 4.161 45.887

20.749 4.677 48.693

21.357 5.061 50.550

21.983 5.929 48.592

22.627 6.063 53.765

23.290 7.393 50.971

23.973 8.700 39.470

24.675 10.001 23.034

25.398 10.632 13.574

26.143 10.724 -6.893

26.909 10.601 -19.937

27.697 10.476 -19.372

28.509 9.654 -0.399

29.344 7.767 9.765

30.204 6.430 12.347

31.089 5.282 19.261

32.000 4.590 -9.399

32.938 4.942 0.464

33.903 4.085 7.621

34.896 4.091 31.757

35.919 4.417 33.120

36.971 4.728 21.600

38.055 6.431 19.223

39.170 11.710 17.052

40.317 14.000 24.871

41.499 15.474 34.245

42.715 15.290 40.030

43.967 9.676 53.901

45.255 5.998 41.863

46.581 6.504 42.828

47.946 8.219 24.102

49.351 8.919 6.982

50.797 10.070 -0.993

52.285 10.004 1.794

53.817 9.224 -22.105

55.394 8.248 -26.781

57.018 6.400 -38.902

58.688 6.975 -24.881

60.408 6.151 -20.460

62.178 5.594 -15.973

64.000 4.529 -10.567

65.875 3.700 -9.065

67.806 3.224 -5.173

69.792 2.928 -0.442

71.838 2.871 5.384

73.943 2.895 9.608

76.109 2.965 12.382

78.339 3.013 15.430

80.635 3.055 18.042

82.998 3.099 20.603

85.430 3.155 22.714

87.933 3.174 23.872

90.510 3.209 24.674

93.162 3.282 26.269

95.892 3.464 28.820

98.701 3.567 30.323

Can you not fathom how a "8KW" @ 2 ohm amp for example could be "all day err' day" to this sub while at the same time if you found a song that played some of these frequencies hard you could blow the sub up in a hurry?

Those big Sundown coils are 3" 8 layer. General rule of thumb used by loudspeaker engineers is 100W X coil diameter (in inches) X layers. That's continuous power. Your friends probably know what they're doing, play songs with high impedance when they're showing off, and are smart enough to turn it down if they smell something funny.

Using this sort of anecdotal evidence to recommend some rookie runs an amp at half ohm or runs double rated power to a woofer is irresponsible.

I know for a fact your subs weren't getting full power for long because you didn't burn up the coils.

You really don't understand how AC works do you? 1200W square wave = 1800W sine wave period end of story.

If you're implying that the cone isn't making the same number of strokes per second (to cool itself) with a square wave vs. a perfectly rounded sine wave you definitely need to visit an autism specialist.

Draw a graph with a zero line, a +1200 line and a +1800 line and a -1200 and -1800 line. Now draw a sine wave 1800 + and - peaks and shade in the area between 0 line and the waveform. That is your RMS average power. You can do the math (peak X .707), use graphing software, or just count the shaded squares of your graph paper to verify.

Now draw a perfect square wave (likely never going to happen real-world) with 1200 + and 1200- peaks and shade in the area. You will find that it is the same (I'm using 1200 and 1800 for simple rounding but it should be close enough to illustrate th

e point).

I'm saying it's seeing more power without cooling more when it gets a square wave

 

[hispls 5,000+ posts]

Yea not sure why that video came out crap. But averaging like 158-159db

Couldn't make out the Termlab display in the vid. Very impressive average!