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The amp gains at your HU max clean voltage setting is more important
Than the power handling.

The 250 hz low resistance peak could be only within a fraction of a second, any good 6.5 " 60w speaker can handle 300w for a millisecond.

And the reason for extra power is to fill areas of those milliseconds where resistance is high and low power is lower.

The 60w amp with a 60w speaker matching is just an industry myth, this means even if you set the gains at 160w in real time, the speakers may only reach 70w max even at high playback level.

In fact I tend to not trust amps specs unless they are under rated, and even if an amp rated at 100w is right on with ratings I would choose to set gains 5-10% lower than rated, to simply avoid pushing the amps limits even though in real time it would never be an issue.
 

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Discussion Starter #23
The amp gains at your HU max clean voltage setting is more important
Than the power handling.

The 250 hz low resistance peak could be only within a fraction of a second, any good 6.5 " 60w speaker can handle 300w for a millisecond.

And the reason for extra power is to fill areas of those milliseconds where resistance is high and low power is lower.

The 60w amp with a 60w speaker matching is just an industry myth, this means even if you set the gains at 160w in real time, the speakers may only reach 70w max even at high playback level.

In fact I tend to not trust amps specs unless they are under rated, and even if an amp rated at 100w is right on with ratings I would choose to set gains 5-10% lower than rated, to simply avoid pushing the amps limits even though in real time it would never be an issue.
So how would you set the gains at max unclipped HU volume, if your amps delivers way more power than the speakers can handle?
 

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So how would you set the gains at max unclipped HU volume, if your amps delivers way more power than the speakers can handle?
You turn up the head unit to about 3/4 volume, not 100% so you have a little wiggle room for low volume recordings. Start with the amp gain at it's minimum setting, make sure your crossovers are set, play some music with plenty of good, clean bass around your mid HPF (80hz I think you said), and slowly turn up the gain until you either reach the SPL you want, or start to hear distortion.
 

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Discussion Starter #26
But I'm really bad at hearing distortion, so when I hear distortion it might be 15-20%. So I wouldn't know how much to back down.
Maybe I could use my umik-1 mic to detect the distortion, but without dismantling the umik max spl is 112dB. Would my SB17 drivers distort before 112dB, and if so what's the best way to detect power related distortion with a umik-1 ?
 

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But I'm really bad at hearing distortion, so when I hear distortion it might be 15-20%. So I wouldn't know how much to back down.
Maybe I could use my umik-1 mic to detect the distortion, but without dismantling the umik max spl is 112dB. Would my SB17 drivers distort before 112dB, and if so what's the best way to detect power related distortion with a umik-1 ?
If the distortion isn't obvious, it's not harmful. Like I said before, watch the cone while you listen. There's no reason to complicate this. O-scopes and measurements aren't necessary for setting gains. If the cone looks like it's reaching it's limits, back off until it's not, if the speaker starts to distort, back off a bit.

Something to consider, at 30hz we can tolerate 100% distortion. At low frequencies there can be loads of distortion, and it doesn't bother us. Paying attention to have far a speaker is moving, and listening for obvious problems is easy, and effective.
 

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Something to consider, at 30hz we can tolerate 100% distortion.
maybe you can? tbh, i think this is a pretty dangerous blanket statement. what kind of distortion? even order? odd order? IMD? linear? Yes, its not as easy to detect distortion at lower frequencies, but i'll be damned if i cant hear it or can "tolerate" it
 

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maybe you can? tbh, i think this is a pretty dangerous blanket statement. what kind of distortion? even order? odd order? IMD? linear? Yes, its not as easy to detect distortion at lower frequencies, but i'll be damned if i cant hear it or can "tolerate" it
I specifically said "tolerate" and not "hear." You can hear it before it reaches 100%, no doubt, but most people will tolerate a lot more distortion than they realize before things sound bad, at low frequencies.

https://www.axiomaudio.com/blog/distortion

It's actually 40hz, not 30hz.

Also mentioned in that article:
"For detecting distortion at levels of less than 10%, the test frequencies had to be greater than 500 Hz" meaning people couldn't even detect (hear) 10% distortion until after 500hz. Below that, we tolerate distortion well.
 

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Discussion Starter #30
But I can't see the cones movement without unmounting my door panel. I have removed my door panels so many times, I really don't want to do it again.
Seriously no one knows how much power the SB17 can handle with a 24dB highpass xover at 80Hz??
 

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But I can't see the cones movement without unmounting my door panel. I have removed my door panels so many times, I really don't want to do it again.
Seriously no one knows how much power the SB17 can handle with a 24dB highpass xover at 80Hz??
It doesn't matter if anyone knows. Your exact speaker will not handle the exact same power as every other one that was manufactured, and with dynamic music, you won't have any way of knowing how much power is actually going to them. How about this, if you're so worried set them with a DMM and use your 60 watts to determine voltage, set your gains to that voltage and see how they sound. If they get loud enough, and don't sound bad, you're done.
 

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My amp certainly doesn't clip a 30W, so I assume you're referring to my SB17 speakers? Do speakers really clip? I know speakers normally response with no linear, power compressed output when the power get to high. Is this what you believe happens above 30W ?
My umik-1 handles 112db or 130db if I set it's gain at 0, so I don't think I need the linked spl meter.
I don't really care how many db I'm playing I just want the ability to go as loud as my speakers can handle.
The peak power of the amp is 300W,

The music usually has a crest factor of ~15...
Which means that the peak is 40x higher than the RMS.

So by ~10W RMS you should be close to clipping the 300W amp.

If you want to go "as loud as they can handle", then get louder speakers.
Or modify your expectations to be "as loud as is need[ed/B]".

Either you quantify it, or one guesses.

Those speakers are nothing too special, so just put them in and try it.
 

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Discussion Starter #33
My amp certainly doesn't clip a 30W, so I assume you're referring to my SB17 speakers? Do speakers really clip? I know speakers normally response with no linear, power compressed output when the power get to high. Is this what you believe happens above 30W ?
My umik-1 handles 112db or 130db if I set it's gain at 0, so I don't think I need the linked spl meter.
I don't really care how many db I'm playing I just want the ability to go as loud as my speakers can handle.
The peak power of the amp is 300W,

The music usually has a crest factor of ~15...
Which means that the peak is 40x higher than the RMS.

So by ~10W RMS you should be close to clipping the 300W amp.

If you want to go "as loud as they can handle", then get louder speakers.
Or modify your expectations to be "as loud as is need[ed/B]".

Either you quantify it, or one guesses.

Those speakers are nothing too special, so just put them in and try it.

In bridged mode my amp delivers just about 2x350W RMS certified.
My speakers have been installed for quite a while, so I don't need to put them in.
I don't know what speakers you define as special, but where I live renegade and rainbow are considered really fine speakers. So a speaker in league with scanspeak & dynaudio, is considered special.
I'm certainly not going to change them, it's just that when I invest in something I want that something to perform as optimal as possible (within reasonable limits)
 

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Wow, if the amp puts 350 bridged, why bridge it then? It sounds to me like you need to list your whole system to evaluate practical, effective and efficient options to help you out.
 

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You are overthinking what power is actually required for midbass or tweeters. Having an amplifier that has lots of headroom is great for those musical transients but setting the gain for mid woofers and tweeters to maximum power isn’t necessary, especially if your amplifier is capable of putting out 300 watts per channel. If I remember right the SB17 is also fairly efficient (~90 db) so it doesn’t need tons of power to get loud for its intended purpose.

The subwoofer will require the most power so this is where you want to set the gain on the monoblock amplifier to maximum power. Then you adjust the gains for the midbass drivers and tweeters so that they match your target curve once you’ve set your EQ for the left and right sides and so that they will match your sub stage without having to attenuate tons later in the DSP. I used to set gains on my amplifiers, even for tweeters, to maximum power, then I had to attenuate them greatly within the DSP to get them to match my target curve. All this did was raise my noise floor and create more work while tuning. I was being told I had to set my gains with a scope or DD1 on a 75-100 wpc amplifier for a tweeter that needs 6 watts to get loud! I had one guy claim he put 250 watts into his tweeters and he honestly believed that was happening :laugh:. Your tweeter will need 15 watts at the most to match most mid woofers and sub stages unless you have something really crazy like the SPL guys sometimes do.

I ran the NVX X series (same as SB17) for a year and they are very good sounding mid woofers, especially the mid range part like Hillbilly said. I only used an amplifier that puts out 75 wpc into 4 ohms and 150 wpc into 2 ohms but NVX actually rates these for 50 watts each nominally and probably because they don’t have the help of the air spring they would have in a small enclosure. I’ve run my Pioneer D8604 to tweeters that have a rating of just 15 wpc and stock factory Ford mid woofers with a 25 watt stamp on them for a year without any issues and I definitely turned it up at times but never had an issue. Where you put that HP filter and the slope you use will greatly effect the power handling too and since you have yours at 80 Hz and 24 db I think you should be fine.
 

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In bridged mode my amp delivers just about 2x350W RMS certified...
...
Maybe we need to define what RMS means?

With a 1000-Hz tone running the full voltage excursion then I believe your amp can deliver 350W.

0dBFS is full voltage range, where dBFS means dB "full scale".

Now look at Grandpapy's old vintage tape deck... you'll see a VU meter on there.
VU stands for "Volume Units", and usually the relationship is
0 VU = -18 dBFS
(Sometimes -14 dBFS)

Basically the musical peaks are ~14dB above the musical RMS.
And grandad set the VU to cruise around the edge of the red at 0 VU.

Unless you are playing tones, then at above the subwoofer range you will have -13dB, or a factor of 20, between RMS and clip.
300W/20 is 15W... maybe with a little clipping it is 30W RMS, which is really too loud to listen to, unless you want Grandad type of hearing at a young and tender age.

An SPl meter would tell you that a350W RMS is way above optimal.

Most speakers are rated in SPL dB at 1W/1M.
Most amplifiers are also rated in THD at 1W RMS.

1W RMS is about 30-40W peak in musical content...

Hence there is no way your amp will ever be "delivering 350W" playing anything that sounds like music.


...
I don't know what speakers you define as special, but where I live renegade and rainbow are considered really fine speakers. So a speaker in league with scanspeak & dynaudio, is considered special.
...
I want that something to perform as optimal as possible (within reasonable limits)
Special would be:
1) Some cheap rate speakers designed for low power...
Or alternatively
2) Some really expensive horns, or ribbons, which may also be designed for low power.

I have scanspeak, and they are good, but not special or overly "precious".
They are not "magical special".

For optimal, just turn the gain all the way down, then when tuning only crank it up to what sounds good.
(Don't try to blow the ear drums out the opposite side ear.)
 

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But I can't see the cones movement without unmounting my door panel. I have removed my door panels so many times, I really don't want to do it again.
Seriously no one knows how much power the SB17 can handle with a 24dB highpass xover at 80Hz??
I gave mine 300 watts. 2 channels bridged from an Arc Audio XDi 1100.5. It made them come alive Vs. the 125 watts they were getting before. They handled it fine. But just because they were hooked up to 300 watts doesn't mean they were getting 300 watts. I never actually measured anything with a meter. All speakers in my system were level matched to the subwoofer.
 

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Seriously no one knows how much power the SB17 can handle with a 24dB highpass xover at 80Hz??
It can be determined using test tones, but that's not music. Music is dynamic with the actual power (wattage) changing by the second. The best advice I can give you is high pass them properly and set the gain on whatever amp you want to not clip. If that reaches the volume you want then great, if not get a bigger amp.
 

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Discussion Starter #39
I gave mine 300 watts. 2 channels bridged from an Arc Audio XDi 1100.5. It made them come alive Vs. the 125 watts they were getting before. They handled it fine. But just because they were hooked up to 300 watts doesn't mean they were getting 300 watts. I never actually measured anything with a meter. All speakers in my system were level matched to the subwoofer.
Thanks for sharing your experience. I upgraded my amp and had a similar experience, the SB17 sounds better with 350W compared to 100W.
Of course I will be level matching the woofers to my sub and tweeters, just figured it would be safer to turn the gains down to limit output and use my HU to match the levels.
But I spent 5 hours tuning my system yesterday, and overall very pleased with sound, so I don't think I will adjust the gains until I get another car.
 

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Thanks for sharing your experience. I upgraded my amp and had a similar experience, the SB17 sounds better with 350W compared to 100W.
Of course I will be level matching the woofers to my sub and tweeters, just figured it would be safer to turn the gains down to limit output and use my HU to match the levels.
But I spent 5 hours tuning my system yesterday, and overall very pleased with sound, so I don't think I will adjust the gains until I get another car.
I'm not sure about the science behind this. Possibly more Headroom. Those speakers certainly needed more power. They got louder, had more authority, more punch. They are still going strong after about a year on that much wattage. Like I said, I don't understand why. At 125 watts they were still receiving over double the recommended wattage, but just didn't have great output. They are still the weak link in my system. I purchased Audiofrog GB60's about two months ago but unfortunately have been too busy to install them.
 
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