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Behringer NX3000 sufficient to drive Dayton Audio UM15-22 15"


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Hi Team

 

Maybe a dumb question, but I have a  habit of buying things, and then buying again as I went wrong the first time around. I am looking to build my own subwoofer. The amp is throwing me off a little though. I was initially going to use a plate style amp which screwed into the back of the subwoofer box, but started looking at cost effective alternatives as they get pretty expensive once you go past 500W RMS. The subwoofer is a Dayton Audio UM15-22 15", 800W RMS, Peak 1600W. I was looking at the specs on the Behringer NX3000, and read that its most likely closer to 2000W RMS, which really, should be more than enough power to handle one subwoofer. I also read while searching on Google, someone had issues with this amp maxing out on one subwoofer, and a red light coming on as the amp was reaching its peak.

 

Would the NX3000 be enough to get maximum potential out of the Dayton Audio UM15-22 15"?

 

Also, Is there any value in paying more for the NX3000D? I still can't figure out if DSP is really necessary as some of the plate amps I was looking at don't mention DSP.

 

Thanks again for your input.

 

Andy

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Hi Andy,

 

The nx3000d will definitely work for the um15-22, a lot of people use the same amp to drive the um18-22 and sometimes even two of them but obviously not to their peak.

 

the dsp is required for diy subs to make the most of them and to also limit the sun from over excursion through adding in limits based on your box simulation ( mostly for ported boxes). But you can get around this using a mini dsp instead if you have one handy/ want one instead 

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Thank you for your help. I realise I may have not included enough info. I should have added, I will be connecting the Behringer amp up to a Yamaha RX-V385 receiver. Since the receiver already has DSP, can I get the NX3000 instead instead of the NX3000D?

 

The box will be a ported box, with the slot along the bottom.

 

Thanks again for your help

 

Andy

 

 

Edited by Insaini
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You still need the dsp to protect the driver as the amp doesn’t have those settings in it. The dsp In the receiver is for the sound and eq correction.

 

If you want more info have a look into the vbss or Marty cube builds floating around on the internet as they have the pre done dsp specs 

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On 23/12/2020 at 12:10 PM, Insaini said:

Would the NX3000 be enough to get maximum potential out of the Dayton Audio UM15-22 15"?

I think so

 

On 23/12/2020 at 12:10 PM, Insaini said:

Also, Is there any value in paying more for the NX3000D? I still can't figure out if DSP is really necessary

it will provide more options/future proof your sub amp down the track, even if you don't use the DSP now

 

16 hours ago, Insaini said:

The box will be a ported box, with the slot along the bottom.

 

15 hours ago, Cdj_91 said:

You still need the dsp to protect the driver as the amp doesn’t have those settings in it.

agreed - ported/passive radiator/tapped horn subs all experience a significant increase in driver excursion below the "tuning" of the box - a high pass filter is typically used just below the box tuning.

 

Just a question - is there a specific reason you want to build a ported sub? eg you need the additional efficiency provided by the port?

I think you'd get enough SPL just using a sealed enclosure with that driver, and the enclosure can be smaller (or any size really).

Sealed enclosures just make the whole design easier, and will sound right from the get go.

Ported enclosures are much harder to get right, and bring issues with chuffing from too high air velocity through the port/slot, and varying acoustic response with SPL.

 

Ported enclosures do provide an increase in efficiency over sealed down to their tuning frequency, which is useful where maximum SPL is a requirement (eg sound reinforcement/PA applications), but for domestic applications this is rarely needed.

A simpler and much more predictable approach is a sealed enclosure with EQ to push the speaker lower with enough amp power so the amp doesn't clip...the EQ to push the sealed driver lower will consume plenty of amp power - but I don't think the NX3000 will run out.

 

Also sealed subs don't require a high pass filter for driver protection - their excursion is predictable without the major increase below the port tuning of ported enclosures.

 

I'm a lazy DIYer - when I make sawdust I want it to sound right on first listen...or after tuning without having to make more sawdust.

 

I do run a DIY tapped horn sub - but Paul from Red Spade designed it, with the amps/drivers that are in it - I just built the box to his design.

 

I've been meaning to design/build another sub for ages, just as a "filler" sub to augment the "heavy lifter" tapped horn - I've got the driver and amp...just need to make some sawdust.

It will be sealed for sure.

 

I've got no issue with ported subs...well designed/implemented they sound great...just saying that less effort needs to go into sealed sub/s for equivalent outcomes.

 

cheers and merry Christmas,

Mike

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I use one to drive an 18inch Electrovoice sub without any problems. You're looking at 3000w into 8ohms in bridged mode.

I paid $350 for mine through Faceache marketplace.

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so you feel say 2x 15" sealed subs, for a diy noobie, is a much easier project. i have actually joined avs forums and researched some diy but what talk about is not cheap here and most of the technicalls go over my head easily... is there an aust. site to get the info from

 

ie what driver, box size/materials etc that relate to gear here we can actually get.. i mean parts express hundreds of $$$ for a driver, come on.

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Hi Team

 

I really appreciate all the input. I will go ahead with the NX3000D as there is a sale on tomorrow, so I can get it for roughly $500 new. Not sure if I will be lucky enough to find it cheaper than that. The subwoofer might be an issue. I have been looking at parts express and they are badly backordered. I might follow Mazza's lead and opt for the Type R Alpines instead, in a marine grade plywood box, maybe go for 2 x 12 inch units instead, as that will bring my cost down quite a bit (used) and I don't need to wait 4 to 5 months.

 

The reason I want to go ported is to make sure I get maximum impact out of the sub/s, and don't need a stronger amp to achieve it. I read that sealed boxes need twice to three times more watts than a ported unit. Having said that, my theater room is not huge at all, so I might be going way overboard. Its only 3.8m x 4.8m with a ceiling height of 2.4m, Carpeted floor, works out to be 1545 ft³. I read I could just get away with 1 x 12 inch. Since I am building this myself, and have space in the room, I figured why not go a little overboard?

 

Hi Hopeful Guy. I'm like you, building the box doesn't worry me as I have done harder things than that, its the tuning side. I'm new to this, but eager to learn. I will go ahead and do something similar to the below, and see how I go once built

 

https://www.avsforum.com/threads/alpine-swr-1223d-budget-build.2963622/

 

Merry Christmas all.

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Thanks Mike. You have really given me something to think about. Maybe sealed might be the best option as it could be plug and play once built. My only concern is, if I decided to add a 2nd sub (I am contemplating it atm since parts express don't have 12 or 15 inch UM's in stock) the NX3000D will not be enough. I am guessing, and I could be wrong, to power a 12 inch sealed sub like the UM12 , I will need maybe 1500W RMS per channel? Again, I could be wrong, but my understanding is the NX3000D will deliver only 1000W per channel if I run 2 x 2ohms Subs. 

 

Maybe I am over thinking this all. I will see how I go tomorrow, and if its only a tad more to get the 6000D, I might just go down that path and go sealed box from their

 

Thanks again

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10 hours ago, Insaini said:

I read that sealed boxes need twice to three times more watts than a ported unit.

you could easily need 3-9dB of boost on a sealed unit - 3dB is twice, 6 dB is four times, and 9dB is 8 times the power...but you need to model the SPL/power/excursion in a tool like WinISD - does it matter if the ported unit was drawing 100W and the sealed unit needed 800W (ie 9dB of boost) when you have an amp that can deliver 1500W?

 

I completely accept running 800W continuous into any sub will melt the voicecoil very quickly, but music isn't like that...well maybe some EDM, certainly not movies.

10 hours ago, Insaini said:

I read I could just get away with 1 x 12 inch

IMHO a single 12" is getting a bit small for a "proper" sub - part of the fun of DIYing is going a bit overboard on drivers - 2 x 12" better, 2 x 15" better again 👍

Whether a single 12" is enough comes back to your SPL and low frequency targets in your room - 110dB @ 30Hz is very different to 110dB at 20Hz

 

Tools like WinISD will guide you on the SPL/excursion/power required for ported and sealed boxes.

 

Dual subs, although a bit trickier to integrate well, will provide smoother "in room" bass, especially across multiple seats.

As long as you have the ability to provide separate delay and EQ to each sub, a lot of the hard work with integration of dual subs is made easier with free tools such as Multi Sub Optimiser and REW (just need a uMike and stand)

 

cheers

Mike

 

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17 hours ago, hopefullguy said:

ie what driver, box size/materials etc that relate to gear here we can actually get

have a look here: http://www.theloudspeakerkit.com/loudspeaker-components/loudspeaker-drivers/?rf=va&va=170

but I'm not sure what stock they have on hand - eg the Dayton UM15-22 15" Ultimax DVC Subwoofer 2 ohm Per Coil is not avail till Apr 21 !!!

Deep Hz Audio used to sell drivers, but none seem to be on their website - but worth contacting them https://www.deephzaudio.com/index.html

RedSpade do the Rythmik kits http://www.redspade.com.au/audio/rythmik.php - if building a Rythmik sub I would recommend getting the driver and amp together - Rythmik run an active servo feedback system to linearise the driver travel

 

I run dual Rythmik 12" and plate amps in my tapped horn sub - I can recommend Rythmik subs.

 

for box size just use one of the free modelling tools (eg WinISD) - I haven't used it in a long time, but others here on SNA are highly proficient.

WinISD can plot driver excursion and SPL based on power input, once you've loaded all the driver specs.

 

Regarding box materials - it doesn't matter much - I just use 19mm ply, doubled for the front baffle, with plenty of bracing.

 

18 hours ago, hopefullguy said:

i mean parts express hundreds of $$$ for a driver, come on.

A decent sub driver with shorting rings, decent magnet, good Xmax etc is not a cheap bit of kit to manufacture.

We don't make them in Australia, and they're heavy, so shipping is expensive to get them here.

 

Worthwhile investigating car sub drivers - they bring shipping container loads out so the economies of scale work in our favour - and there'd be plenty of "for sale" options available.

 

An advantage of sealed subs is that the driver specs don't make a massive difference to the sub's frequency response (FR)...ie if you chose brand "x" of a 12" driver cos it was on sale and ridiculously cheap, but managed to blow it up because it was actually rubbish, you could swap it out for a better driver, and a bit of EQ would provide the same response (with the caveat that the better driver will possibly be deeper/have a larger magnet, so the internal bracing of your box may get in the way...adding another layer of front baffle would be the easy fix).

This approach doesn't work as well for ported enclosures - the box size and port length/diameter are closely linked to the driver specs - the box tuning will be different for different drivers. 

 

cheers

Mike

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Well, DJ City had their 15% off sale this morning. Due to Covid, we stood in the sun for an hour before being able to get in, not the stores fault though. Picked up the NX3000D, one piece of the puzzle sorted :)

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I should re-learn how to drive WinISD, but the key reason I haven't is my first goto tool for modelling driver response in a sealed box is a very simple spreadsheet from TrueAudio I found on Rod Elliot's site about 25 years ago for modelling Linkwitz Transforms.

WinISD does lots more, but the TrueAudio spreadsheet only needs the driver Fs, Qts and Vas, and your chosen box volume to show you the response in a sealed box.

Note you'll need Microsoft Excel...maybe Google Sheets could manage it - I've never tried

 

Rod Elliot's article on the Linkwitz Transform

https://sound-au.com/linkwitz-transform.htm

 

Link to the TrueAudio spreadsheet on Rod's page

https://sound-au.com/download.htm#lxfrm

You want this one

509680135_LTdownload.thumb.png.4096e19965b0e8bd539b96c3e45ac557.png

 

You input Fs, Qts, Vas and box volume on the "box" tab - if using litres then input Vas and box volume as -ve numbers.

The Qtc (Q of the driver and box working together) is calculated.

You can learn a lot by looking at the calculated response (graph and the other tabulated results), and adjusting the box volume up and down.

 

The lowest F3 achievable (ie where the response of the driver in the box drops by 3dB) in a sealed box (without EQ) is where the calculated Qtc is 0.707.

 

For the Dayton 15" driver in a 178 litre box:

590662511_dayton15inch178litrebox.png.9ff3158c8e32abb222e0972daaa153a4.png

 

Reducing box size will increase Qtc above 0.707 and you'll get a bump in low frequency response prior to rolloff and then a steeper rolloff.

Increasing box size will reduce Qtc below 0.707 and you'll get droop in the pass band prior to rolloff and then a slower rolloff.

 

Don't get too caught up in building the "ideal" box size at this stage...with sealed enclosures you can add EQ to get the response anywhere you want within the limits of amp power and driver excursion.

 

The real magic of this simple spreadsheet comes with the "Linkwitz Transform Calculator" tab - I haven't built a Linkwitz Transform analog pre-amp circuit since going to DSP 20 years ago - but this tab shows you the quantum of EQ you'll need to push your driver/sealed box down to your target frequency.

 

On this tab you input the target resonant frequency f(p) - not quite the target F3 but close enough - I usually input 20Hz, and for the target Q(p) I usually use 0.707.

 

This is the EQ/Gain required for the Dayton 15" driver in a 178 litre box to push it down to around 20Hz

498653928_dayton15inch178litrewithEQ.png.48688aca8a17760a17dc3ba0a741c463.png

 

 

In the spreadsheet you can hover anywhere over the red curve and it will show the gain needed - a bit under 7dB.

 

What's much more interesting is to go back to the Box tab and muck some more with the box volume...

...remember a larger box had a Qtc of < 0.707, higher F3, droop in the pass band, but slower rolloff?

Increasing the box size to 300 litres requires less EQ/boost

1931378406_dayton15inch300litrewithEQ.png.c32f574412eb3dea7d091f80f2d6f1cd.png

A bit under 5dB (compared with 7dB) - if you have reasonable headroom on your amp, maybe not worth bothering with the bigger box (ie 300 litres vs 178 litres).

 

Let's try a smaller box - say 100 litres

396788796_dayton15inch100litrewithEQ.png.53bdebf5d61252e6eba82619f13ee8de.png

Around 10dB of EQ/gain required to get down to around 20Hz in the 100 litre box - this amount of EQ is a lot.

As I mentioned above:

On 26/12/2020 at 8:22 AM, almikel said:

you could easily need 3-9dB of boost on a sealed unit - 3dB is twice, 6 dB is four times, and 9dB is 8 times the power...

WinISD is useful here to model SPL/amp power required/driver excursion...

 

It's worthwhile noting that in the 3 examples above, with the same driver in different sized boxes, the driver excursion won't change for the same SPL at a given frequency - what changes is the power required to get the driver there. 

ie for the same driver/excursion/SPL

  • Smaller sealed enclosures need more power/EQ
  • Larger sealed enclosures need less power/EQ

You still need to keep an eye on driver excursion when applying EQ to subs - I'm a bit rusty but my recollection is that driver excursion increases 4 times with every octave dropped (edit) for sealed subs (end edit).

You can easily soak up all the Xmax (maximum excursion) of sub drivers when pushing them lower with EQ if you have lofty targets of high SPL at low frequencies.

 

cheers

Mike

Edited by almikel
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15 minutes ago, almikel said:

my recollection is that driver excursion increases 4 times with every octave dropped (edit) for sealed subs (end edit).

Theoretically the driver excursion of a ported speaker at resonance is zero - or very little - the port is doing everything...and the amp of course.

Maybe this is reasonable justification for going ported...but I don't think so...

  • I accept that driver excursion = distortion, but below driver Xmax, distortion is typically not audible
  • ported enclosures achieve their boost via resonant behavior of the driver/box/port combination (ie a type of EQ), which is typically not linear with volume/SPL. EQ added by an amp/pre-amp/HT processor will be linear with volume (until clipping of the device).
  • push a ported/passive radiator/tapped horn design below tuning and driver excursion quickly increases to where the driver might be damaged - a high pass protection filter below the box tuning is recommended

For the easiest (laziest) approach to DIY subs I would recommend sealed every time for simplicity...and 2 x 15" sealed subs with decent amplification would hit most people's SPL/freq targets in most rooms...

 

...as much as I recommend sealed subs for the easy/lazy option, and if I was designing a sub I would always go sealed...

 

...but the sub I built for my room is a dual tapped horn designed by someone much cleverer than me - @Paul Spencer - my T20 tapped horn runs twin 12" Rythmik drivers and 2 x 375W Rythmik plate amps (1 for each driver)  - 750W total - but in a really big box - 2400x600x300mm.

This sub in my room is pretty flat to 20Hz at reasonable SPL rolling off under 15hz.

 

The tapped horn design/large box brings plenty of efficiency over a simple sealed box design as per Paul's blog post:

http://redspade-audio.blogspot.com/2012/02/how-does-sensitivity-of-tapped-horns.html

 

Hoffman's iron rule always applies - pick any 2 out of:

  1. small box
  2. low frequency response
  3. efficiency

Choose your own compromise...

 

cheers

Mike

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