Eminence NSW6021 21" sub users - which amp are you using?

Haven't tried mine in a box unfortunately. My PLD4.5 seems to drive them fine in free air but that's not saying much.
Look for used high power QSC Powerlights/Plx, Crest Pro 200 series, Crown Itech, Powersoft K series, SpeakerPower, Lab Gruppen etc. Tons of old boat anchors out there as well. Crown Macro-Tech, Crest Pro 001 series, Peavey, QSC RMX 3-space models, EV P series.

Lots of HT guys buy Sanway Lab Gruppen clones. Actual Lab Gruppen amps will soon be made in asia.
 
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kipman725

Member
Paid Member
2007-06-10 12:41 pm
Warrington
the kind of driver will take the most powerful available amplifiers, bridged without serious danger of thermal voice coil failure, so if you want the most out of the driver look at amps like: Powersoft X4L, Powersoft K20, Speaker Power, Lab Gruppen. Most important spec will be the maximum voltage output of the amp for peaks, the Powersoft also have real power limiters which can save the driver from thermal failure if sustained low crest factor program material is played at max output.
 
The Crown MA12000i bridged mono is rated 7kW into 4 ohms, 8kW into 8 ohms (20ms).
20ms is only one cycle of 50Hz...
Eminence rates the "6 ohm" NSW6021 for 10kW peaks, it could handle the peaks from a MA12000i with dynamic music.

Subw00er tried the Crown xls2502, which only is rated for 1550 watts bridged mono into 8 ohms, 2.4kW into 4 ohms, so has yet to hear around 6dB of the NSW6021's peak potential.

Art
 

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The Crown MA12000i bridged mono is rated 7kW into 4 ohms, 8kW into 8 ohms (20ms).
20ms is only one cycle of 50Hz...
Eminence rates the "6 ohm" NSW6021 for 10kW peaks, it could handle the peaks from a MA12000i with dynamic music.

Subw00er tried the Crown xls2502, which only is rated for 1550 watts bridged mono into 8 ohms, 2.4kW into 4 ohms, so has yet to hear around 6dB of the NSW6021's peak potential.

Art

Art,

The 4ohm stereo ratings are continuous output - it's just the 2ohm ratings where burst and continuous ratings differ.

A single driver taking the full force of a bridged K20 is certainly impressive, though.

Chris
 

kipman725

Member
Paid Member
2007-06-10 12:41 pm
Warrington
Power Handling Deep Dive - YouTube

this level of power handling is also claimed by B&C, they state most field failures of the largest drivers are due to over excursion and not thermal. They also state that long term thermal power handling is limited by the motor structure heating up beyond 100c beyond which the adhesives holding it together start to fail. I have had (far cheaper) drivers fail due to thermal failure of adhesives in the motor so I find this believable:
measuring excursion - Bass Gear - Data-Bass Forums
(observe that the coil apart from friction damage is not at all burnt)

I think X4L is the most powerful sub amp at the moment? (as it can get the most voltage swing)

More budget options would be stuff like this:
Oem & Odm Class D Stereo Amplifier, The Best Class D Amplifier
(power ratings table is offset on the higher power models is actually 4200W*[email protected])
 

Subw00er

Member
2020-10-16 9:34 pm
Most of the amps you suggest Kipman/Chris are way out of my budget, and I am not sure I trust or want to support the china clones for personal reasons.

I contacted Eminence and they used the PL380 (among others I'm sure) for testing. PL380 Power Amplifier – QSC

Its a little bit rich for me, so I was thinking about going with a Crown XTI 6002 which can be found for a little less and only has slightly less power, but still a lot more than the 2502 I tested.. XTi 6002 | Crown Audio - Professional Power Amplifiers

I have a question though to make sure I'm not entering a rabbit hole.. My goal is not to get more output per se. Even with the crown 2502, I had gains only 1/2 up - any more and it was unbalanced with the rest of the system and ruined movies..or my ears.

What I feel I am missing is accuracy. So, will these huge horsepower amps give me that immediate dynamic ability to control the driver accurately? I would suppose an amp with the larger watts or caps would be best for me, right? I am not an expert on amp design, especially D class, but I look inside these D class pro amp cases and all I can think is .. what is this marketing crap, look at all of these puny boards and caps! I do recall that from my car audio days, when we added .5-1 farad caps to our cars, the drivers all sounded a lot better because the amp wasn't starving for power when those big bass notes hit. It still confuses me how these little D class amps can produce the immediate power required for such a huge subwoofer - thats a lot of moving mass to speed up and slow down, right?! I think what I'm talking about is headroom, right? I dont know how to look at the specs and decipher which amp has huge headroom.

I'm not really looking for a schooling here. I'm sort of brain numb trying to find an amp for these things and decided to just throw a bit more money at it to try and make it work. If I have to spend another $2500+ to get this sub to perform, I think I'll just give up because that becomes really hard to rationalize - I might as well just go buy a JL Audio Fathom or big M&K sub and be done. I went into this DIY effort thinking that I'd buy this budget enclosure and up-spec the woofer a bit because people said it was more musical and accurate than the um-18, and a NX3000 was going to power it fine, but that simply is not the case based on my experience.

I can rationalize an amp in the $2000 range, which means it probably has a used street value of near $1200ish. I really don't want to spend more than that unless it REALLY mattered and would solve my problem.

So in summary, if my goal is to make the sub more accurate, not louder, what is the right amp?
 
That sounds like a eq problem. Good bass at the listening position isn't a plug and play situation in most rooms. You'll need to do some kind of measurements or at the very least run a signal generator to identify major peaks and dips in the response.

Have you heard this sub outdoors?
What mains are you running and what kind of crossover?

You might need to move the sub to a different position if you can't get it working in its current position.
Positioning the sub as close to the couch as possible then delaying the signal to match the mains is one way to minimize room interactions.

It's a common mistake to blame gear early in this hobby. There is no instant fix unfortunately. Luckily there is tons of information and tools available for free if you have a little time. That JL Audio sub does the calibration automatically but it cost quite a bit and won't outperform what you have when both are configured optimally.
 
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kipman725

Member
Paid Member
2007-06-10 12:41 pm
Warrington
All solid state amps that are not faulty or of very bad design will sound the same until run into clip driving a sub so if your not running into the limits of your amp then the problem lies elsewhere (probably as ErnieM says, EQ).

Your amp has clip indicators which (if they operate like other crown amps I have worked on) indicate when the output of the amplifier is no longer equal to the input of the amplifier multiplied by a gain (non linear behavior), they are a bit insensitive only really indicating high levels of distortion. As a sanity check that you are not clipping on transients you might want to check what voltage a full scale sine wave from your source results in at your amplifier output terminals to verify that its not beyond the amplifiers output capability.
 
With the disclaimer that I'm not an "NSW6021 user", a LOT of the guys who have insane bass power requirements over on AVSforum use Sanway FP14000 Lab Gruppen clones. On a dollar per kilowatt basis they're very hard to beat. Obviously they're not touring grade quality like a real LG but also probably not any more fragile than the cheap pro-sumer stuff the big names offer.

Lab Gruppen FP14000 clone amplifiers | AVS Forum
 

Subw00er

Member
2020-10-16 9:34 pm
Zettariyouiki, I want to avoid a clone for the moment for personal reasons. I dont want to support thieves! I also have heard about reliability issues with these things.

Thanks Ernie/Kipman. I have FULLY evaluated the room and eq settings via a mini dsp over the last few weeks of playing around with and learning minidsp and REW (w/Umik-1). I posted some stuff over at AVS if you are bored and want to read it (pics/charts are there as you scroll down) MartySub FAQ | Page 268 | AVS Forum

The sub is indoors in a large very sonically dead basement. Mains are dedicated 15amp, or if you mean main speakers, they are Dynaudio Contour s5.4 (If you don't know them, they are pretty high up the Dynaudio totem pole, $10k). Crossover is a mini dsp, 17hz high pass and 60-75 low pass (I play with it, but this seems to be the limit of the high range until I start hearing bad stuff/slop). I've played with REW simulator and placement. I have 4 other subs in the room and have found the best locations over the years by ear and sub crawl, which hilariously (to me) closely matches the REW simulator. My testing was done with and without the other subs with the same result (except I do get some annoying cancellations when they are all on, but thats a post for another day!).

I've tried placing subs near my chair in the past but its a really bad location as I am essentially in the middle of a basement with no back wall, so the room mode is terrible for subs. I'd also hear the woofer/cabinet/port more in that location, which is what I'm trying to avoid.

When using the 2502 I never saw a clip condition. I didn't play it that loud - maybe 80-85db is my normal listening level. Years of car audio competitions in my youth and hifi/HT fun have left me with tinnitus, so I am really careful with my ears these days. I cant actually tolerate over 90-100db for very long before I start ringing. Again, this is not an SPL/DB output problem, its an accuracyproblem.

I've been into high end, audiophile-grade audio for 30 years and I can sort of tell when a speaker is not being driven properly. The eminence is exhibiting all the conditions of an undriven speaker in my estimation.. slow linger bass notes, no impact or immediacy to the notes, trouble blending with the other speakers, no slam or feeling of effortlessness on the part of the amp, easily locating the sub by ear.. All that sort of thing. I know you guys sort of hang on the physics and numbers side of the audio game, but I have a lot of trust in my ears and something just is not right. Maybe I just made a mistake and this is just not a good enough audiophile woofer, and I should have gone for a more traditional home theater driver.

BTW I emailed again with Eminence and they said that the Crown xti 6002 would be ideal for the eminence 21 (they knew some folks using that combo). I think I'll give that try?! Looks like they are $1200-1500 on the used market which is doable. I just worry... I'm sure it will give me more output, but does that also mean more control/accuracy too?! :) Appreciate the help/opinions.
 
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Graphs look good, box looks good, hard to say what the problem might be given that your other subs sound good in the same area.

Maybe it is the amp...just for kicks try flipping the polarity. Also try no eq if you haven't yet. Big boxes can still sound a bit hollow up high even with a decent amount of bracing. Maybe stuff it with a lot more damping if all else fails.
I have experienced "break in" with large pa woofers as well. I would clip the amp and results were underwhelming. Then they would just open up after awhile with nice punchy bass even at lower levels. Let us know if anything improves.
 
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Subw00er

Member
2020-10-16 9:34 pm
Yah it definitely could use a bit of break-in I'm sure. I ran a few hours through it freeair while I was building the box, and probably have 20 hours on it so far in the box, but no where near xmax..

That spider is STIFFER than any sub I've owned (lots). I could barely maneuver it by hand. Punchy bass at lower levels.. now you're speaking my language! Maybe I just need the power to overcome those dual stiff spiders and get them moving. I heard of a guy doing it by hand but I was too scared to try...

I did try a polarity change. It did help a little. No eq didnt help. I could try more dampening, but I hear it doesnt have that much of an effect with ported boxes?
 
I have two 16cu.ft. 2x18's boxes I will be converting to 2x21. They are split in half internally, braced, crossed braced with threaded rods, and I can still hear problems if I cross to far above 100hz. I have a good amount of recycled cotton on one side which helped quite a bit.
It's definitely a trade-off between maximum port output and clean upper bass performance. It sounds like you have plenty of output to burn down low. Wouldn't hurt to line all walls. Just leave plenty of space directly around the driver and leave a clear line of sight between the driver and port.
Take a look at how 18 Sound lines their large subs.
Eighteen Sound - Professional loudspeakers

While you're doing that, run it again with some pink noise at high excursion. Very unlikely to hurt it with that amp.
 
I don't undestand why you would need that kind of power in a home setting...

But anyway, I'm a dubhead, and a lot of bigger dub sounsystems use for their subs (mostly an array of 18" scoop horns) older Crest x001 series amp (which are good, but can't give the wattage for this box), or Powersoft K20's as these can take the voltage swings that a high power subwoofer system needs. Many others can't. Full Fatt Audio FFA-10000 can also do that. The problem is always the underpowered psu of those amps that sag when pushed and distort the sound in best case. If your sub needs 10kW it may also be that it needs an amp like that K20 because the psu can't follow the demands of the speaker. Those are expensive (even second hand) altough.