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Discussion Starter · #1 · (Edited)
Subs: e5.12 Subwoofer ( will make a seperate box for each driver and place it under my desk at about 5 feet apart or place in the back of my room at each corner).
Receiver: HT-RC260
Goal: 80% music and %20 HT
Power for subs:? Need a HPF at around 15Hz

Why this sub? I got the A-300 and love it but decided to step it up. I also looked at the 13Av.2 and doesn't seem like it is worth the extra price and weight.

Looking at the graph in BassBox 6 Pro the F3 is 20Hz for a 2.5 Cube box but a 4" port won't fit in the box nor would is be sufficient enough to handle the output.

How would I go about making a sufficient port and or should I make an "L" port instead of regular? If an "L" port, how do I go about making it? I want NO PORT NOISE! I heard some coming from mine and is NASTY.

Thank you!

Nick
 

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One way you could meet your goal, albeit more expensive, would be with Passive radiators. Two CSS APR 12s, with around 900g of added mass give or take, would tune excellently. Power handling would be up at about 950W max with a 2nd order 19hz HPF.

Anechoic F3 would be 28hz and F6 would be 20hz. You'd probably have an in room F3 right around 20hz, possibly as low as 15hz depending on what kind of gain you're getting.

If PRs aren't an option, I would honestly just seal up that excellent looking driver, and then if there's any bottom end missing, use a linkwitz transform and raw power to eq it flat. 2.5 cu ft is a very good size for sealing this driver.

I can model you a slot vent if you like, but you essentially have to consider that it will make your box bigger because it will take up some space of its own. With a 19hz 2nd order high pass filter and a slot vent, you could handle about 1000 watts with a tuning near 20hz.

The real problem with a vented box will be a low, low first port resonance. I would not normally recommend this resonance to be anywhere below 160hz, and this is all the way down at 92hz. This resonance should be an octave above teh crossover frequency. I know you want to tune lower, but the vent resonance is too problematic in my opinion.

One way you could deal with vent resonances might be a transmission line. The T/S parameters of this driver seems to suite a TL very well. I am not great at modelling them, but i could run it through mjk's worksheets tommorow and see what I get.
 

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Discussion Starter · #3 · (Edited)
WOW great info!! Thanks! I will do that big sealed as I can fit it under my desk and looking at my A2-300 in bass box, the sealed is slightly less output but lower end eats it alive and on top of that I have two :D.

what is "use a linkwitz transform and raw power to eq it flat"?

Issue is what power to power them and do I need a HPF?

Front fire VS down fire, any difference?

Note: mainly for music and trying to get that last dB out of the lower octave isn't worth the added noise from the port and the size.

http://www.behringer.com/EN/Products/EP4000.aspx how does that look for a power supply? Does 1.4k into 4 ohms at 2 channels (subs are 4 ohms each).
 

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WOW great info!! Thanks! I will do that big sealed as I can fit it under my desk and looking at my A2-300 in bass box, the sealed is slightly less output but lower end eats it alive and on top of that I have two :D.
I doubt a sealed sub would have more low end unless the vented is really poorly tuned. Sealed subs are excursion limited, while vented subs are more often limited by vent compression.

what is "use a linkwitz transform and raw power to eq it flat"?
A linkwitz tranform is an EQ which will boost the bottom end of a sealed sub to be perceived as flatter.
Extra Amplifier power is what is needed to add EQ boost.

Issue is what power to power them and do I need a HPF?
99% of subs will benefit from a HPF. I recommend it.

Front fire VS down fire, any difference?
Just because there's some slight "placement" difference, it might load the room slightly differently. N Otherwise it'll be about the same. You do trade off a bit of xmax with this kind of mounting though. NOt all subs can be down fired - you need to check sag factor.

Note: mainly for music and trying to get that last dB out of the lower octave isn't worth the added noise from the port and the size.
I agree. But if you do want the lower octave passive radiators will work excellently om 2.5 cu ft as I mentioned earlier, with no port noise.

http://www.behringer.com/EN/Products/EP4000.aspx how does that look for a power supply? Does 1.4k into 4 ohms at 2 channels (subs are 4 ohms each).
The behringer is an excellent choice. It will have a loud fan though, which will need modifying.

Personally I use Tapco J2500 amps. They're essentially the same amp as the behringer EP4000 (both are clones of the QSC 2450) but they use two 12V fans instead of one 24V fan. Because of this, the replacement fans were easier to source for me, as I picked up a pair of Noctua NF-R8 silent fans from NCIX.

And of course, a HPF of some sort is recommended.
 

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Discussion Starter · #5 ·
Seems like a passive looks nice but looking the GD for the PR is off the charts. At 52Hz it decides to be 32 msec at 15 Hz its almost ten times that. The excursion of the passive radiator is almost triple of the main driver. How can this still be used since the response and the excursion is so bad?

I tried finding that amp and is sold out. I want a quite unit and can easily fan mod it. Any other suggestions?

Thanks again for your help as I have a basic understanding of how this works but designing anything other then sealed is out of my league for now.

Seems a HPF of 15Hz does best with a 24Db slope and were/ how can I make my own for this?
 

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Seems like a passive looks nice but looking the GD for the PR is off the charts. At 52Hz it decides to be 32 msec at 15 Hz its almost ten times that. The excursion of the passive radiator is almost triple of the main driver. How can this still be used since the response and the excursion is so bad?
You must be modeling it wrong.

2.5 cu ft
1 x eD e5.12
2 x CSS APR12
900g added mass
19hz 2nd order HPF
950 watts.

Group delay is very much acceptable. only 4.8ms at 52hz, not 35ms. An 80hz 4th order crossover might raise it to 12hz. At the lowest audible frequency, it rises to around 35 to 40ms but this is fine.

If you think you can hear it, it can easily be lowered by using 300g more of added mass (lower tuning) and a lower 2nd order high pass filter IE 17hz, but max power handling will drop to about 800w.

Frequency response is very smooth and optimal for integration into many rooms.

PR excursion doesn't even reach the xsus of the APR12s in my model, as long as you use a high pass filter as I specified.

I tried finding that amp and is sold out. I want a quite unit and can easily fan mod it. Any other suggestions?
Well, the behringer EP4000 should work fine.

Seems a HPF of 15Hz does best with a 24Db slope and were/ how can I make my own for this?
I think a 12db slope at a slightly higher frequency, in terms of overall performance in an extended bass shelf, will usually give superior results. You can build a circuit for it but I just use a miniDSP.
 

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Discussion Starter · #7 · (Edited)
Box: 2.5 Cube
PR: 2 FS: 6.9 QMS:7 VAS:156 CMS:.48 MMS:1000 RMS:3 SD: 505

That gave me near linear results of a ported sub woofer. Group delay at 4.8ms is 40Hz. So it is 2 PR's per one woofer? If so, that is allot of money for four PR's.

behringer EP4000 can't be easily changed as you sad and I require something silent as my PC runs 600 RPM 120mm fans and need it quite as possible.

I don't have a miniDSP and guess I will find a way to create a HPF for this. Would you say a 20 Hz 12dB slope would be perfect? It hits right around my 15Hz -6 (other words my F6 point and would make it effectively my end response as it adds around another -6 dB to it making it stop right there). Sound right?

Note: could I just use one 15" or is two better if I have to go with two? How does this compare to a slot port?

Thanks!
 

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Box: 2.5 Cube
PR: 2 FS: 6.9 QMS:7 VAS:156 CMS:.48 MMS:1000 RMS:3 SD: 505
FS = 6.9 implies 1200g of added mass. The great thing about the CSS passives is that you can play around with added mass whenever you feel like, as it is external. My suggestion, 900g, would have an fs = 7.71 and I feel it would probably be the optimal tuning for balancing out output and extension. The best thing is that you can play around with tuning in YOUR room once you've got it in front of you.

But it seems like now you're modelling correctly.

So it is 2 PR's per one woofer? If so, that is allot of money for four PR's.
Indeed. if you want to maximize low end output dollar for dollar, without running into Vent Compression or Vent resonance issues, I honestly don't see many alternative besides PRs. Sealed is less efficient down low and would require you to pick up two more drivers to match the same output. Still, if it's expensive, then do whatever you feel comfortable with.

One path you could consider would be to make one PR sub, and one sealed sub. Bottom octave frequencies rarely have in room mode issues so one sub would have pretty smooth response, and the second, sealed sub could be used to smooth out response where room modes are problematic. Build the sealed sub's bracing such that someday when you choose to, you can modify it to a PR sub assuming CSS still sells the APR12s.

behringer EP4000 can't be easily changed as you sad and I require something silent as my PC runs 600 RPM 120mm fans and need it quite as possible.
Whoa there, hold on! Just because my Tapco was easier to mod, doesn't mean the behringer can't be modded just fine. Here is a whole thread on it:

http://www.hometheatershack.com/for...rs/3658-quieter-fan-mod-behringer-ep2500.html

With that said, this should be a silent alternative:

http://www.sweetwater.com/store/detail/IPR3000/

Just don't bridge it into 4 ohms. Run it in stereo mode as it is not bridgable.

I don't have a miniDSP and guess I will find a way to create a HPF for this.
I honeslty think miniDSPs are a top notch investment. It would make your life 100 times easier. But here is a link on analog active HPFs:

http://www.subwoofer-builder.com/active-filter.htm

And here is an alternative commercial high pass filter you could consider:

http://www.edesignaudio.com/product_info.php?products_id=657

Would you say a 20 Hz 12dB slope would be perfect? It hits right around my 15Hz -6 (other words my F6 point and would make it effectively my end response as it adds around another -6 dB to it making it stop right there). Sound right?
Model whatever is lowest in frequency while giving you acceptable power handling. Remember, driver excursion may overshoot xmax above tuning because these are low tunings - keeping excursion of the driver and passive radiators is the number one goal as it lets us use more powerful amps with less worries. I think a 20hz filter would work fine. In my model a 19hz filter worked for either tuning. Ultimately it would depend on how much power your final choice of amp has. If you went with a 300 watt amp you might not even need a HPF, but would be sacrificing output.

Note: could I just use one 15" or is two better if I have to go with two? How does this compare to a slot port?
One 15" sub? No, I feel two 12" subs spaced in a room will give you more natural response, even if it costs you a bit of output.

One 15" passive radiator per 12" sub? One APR15 does look like it models nicely with 990g of added mass and even with 1000w does stay below its suspension limit of 33mm excursion.

I do know a lot of people prefer dual opposed identical passive radiators because of how they cancel out box vibrations/shaking/sliding. Make the box very well built and heavy (bracing and triple layer baffle will help....MDF is heavy so use that instead of baltic birch) and it should be pretty well and fine - It seems like a good choice. The biggest tradeoff is that you need a wall dimension that can house a 15" PR.

Go ahead and model other passive radiators though before you pull any triggers :T - different PRs tend to behave differently. Another passive radiator to consider might be the acoustic elegance 15" PRs.
 

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Discussion Starter · #9 · (Edited)
SO MUCH INFO >_<

Found the absolute best: PR:1 FS: 4.9 QMS: 52 VAS: 978 Cms:1 Mms:1100 Sd: 830 and box size is 2.5 cubes.

http://aespeakers.com/shop/catalog/product_info.php?cPath=24&products_id=40

The E5.12 will be front firing and the PR will be on the side. I plan to have 2" MDF all around (3 at the face) and a few braces, will that be enough for this (handle the added movement of the PR)?

Seems 1k power would work perfect for my situation and need to make sure everything below 15.5Hz is gone.

NOTE: what is the dB rating of this sub?????? I have it as 85 dB but on the site says nothing.

I'm also having a hard time finding any passive radiators as well. Parts express is a joke for them :D .


Thank you very much for your hard work. Seeing as how much output I get with this, I think I only need one for now as this will be a huge improvement over my silly A2-300.
 

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I have subs with a single, larger, passive radiators and movement of the enclosure is not a problem. One is one inch thick MDF the other .75" MDF. I'm driving them with a miniDSP and Behringer EP4000.
 

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Discussion Starter · #11 · (Edited)
Thanks, that's good to know. The power supply I decided would be: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-6482 (Behringer EPX3000 Europower). Seems to be out of stock or low stock on many sites and does the power I need and seems it will run allot quieter then the EP4000.

Note: above amp is not good for sub woofer duty since it is not a toroidal power supply :(. Fans I need to run it would be around 12 dB and I think the 500 watt bash amp from parts express is looking mighty tasty right now.
 

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I am a nurse by profession and found the fan mod to my EP4000 to be quite easy. It never overheats or shuts down even with it in the mid 90s in my room. There are those who enjoy modding and those that don't. The EP4000's fan was designed for continuously high output like from an electric guitar or other professional use. Home theater use seldom taxes it. The "real" rating is more like 920 watts per 4 ohm channel.
 
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