Musically subwoofer?

[music2u]

I´ve been told, one Aurasound NS18 will outperform two JBL 2245h below 50hz.

This is easy and not a question of belief: They are both 18" so about the same Sd but the Aurasound has an Xmax of 75mm and the 2245 of 25mm (peak to peak). So an Aurasound should "outperform" three 2245. If you want to break down your house, go and get a decent 2,000 watt class d amp (just kidding ;-) It is one of the most modern and technically sophisticated subwoofer driver out there. But does it match your "vintage" mains?

Before I started the JBL soundbar project, I also considered the Aurasound. I totally understand where you are coming from. From reading your post I believe your heart goes with the Aurasound. So go and get it. There's nothing wrong about it. It's all fun...

[Ruediger]

Impuls compensation is said to reduce the amount of energy that is lost in enclosure vibrations and therefore improve precision, because the impulses of the speakers cancel each other (sorry, I found only a German schematic):

Attachment 75358

I have buildt open baffle subwoofers ("Ripole"). They are very close to the Linkwitz design. They are impuls compensated.

Hey guys, this is voodoo.

Ruediger

[berga12]

From the other side consider also that....more X max means Less Efficiency means more Watt to drive the loudspeaker and more distorsion.

I'm sure that the Aurasound is wonderfull speakers, the price is also not popular.

For an Home usage, your system (I'm speaking about 3 way one...) can be driven with a power from 1Watt to 12Watt with an Output > than 100db 1W 1m.

This Means, that It's enough to put 200W amplifier on a Single or dual 2245h (I would go with Single due to space need...) and The imput could be a combination L+R fully Active, and the main system fully passive without any High pass filter.

even if the 2245 have an average of 90-92db (I think more....) you can easily meet the same output as the main system without any problem, and you are able to shake your house if you want, or Just listen really clean without distortion at 100-105db output (definitively not a low volume...)

More over, you have a piece of history and a full JBL system. You can also try other speakers, for example M2 speakers 2216Nd, in 140L can go as low as 20hz...and many other in the market without the need of running a 18".

Pay attention on the subwoofer speed....you have a really quick response front stage...maybe one of the quickest 15"...





beside that...I also Love the NS18

[Dr.db]

Ok Rüdiger, I won´t worry about the impuls-compensation further more...


I believe one 2245 will be easily enough for the average day listening situation!
But I need the extra headroom for the days I go crazy and I think I would bottom out the 2245 then...

But there is one thing about the Aurasound which doesn´t please me; it is single 4ohm.
I don´t want to drive it with a cheapy plate amp, I´d rather use a professional external digital amp. But these are stereo, I haven´t found a mono-amp yet.
And bridging to the single 4ohm coil of the Aurasound would mean I need a 2ohm stable amp

[berga12]

Go with Hypex UCD module for a mono subwoofer, you will be happy.

you can use the mono module UCD700HG if you need more power, they also have 2000wrms module...

they can run 8-4-2ohm

Or If you have a dual voice coil, you can use a stereo amplifier on 4ohm x channel.

I'm using the UCD400 (2x) for my 2235h and they sound really nice on Bottom spectrum.

[music2u]

Hey guys, this is voodoo.

Ruediger

Is this solely your individual belief or do you have any evidence for your opinion? Have you measured enclosure resonances? Have you auditioned normal and compensated subs in direct comparison?

If you quote, then please in context. I also wrote:

Can you hear it? I don't know but I assume, that room resonances are much more important.

This is the reason why I usually stay away from forums....

[rusty jefferson]

https://www.parts-express.com/dayton...kage--300-7200

I have a friend who recently received a review sample of one of these for evaluation and measurement for an upcoming magazine article. It measured and sounded very good. 4 cubic foot sealed box. You can also buy just the woofer/amp and build a matching box (or 2) for your system.......

The article became available today at audioXpress. You can download just the one issue if you like. Worth the purchase. Thorough article with measurements.
http://www.audioxpress.com/article/g...-now-available

[gibber]

I´m aware of the advantage of two subwoofers, but I only have place for one enclosure.
Have you compared an impuls-compensated sub with a "usual" one ?
Is it just an advantage in theory or can one really hear a difference?

actio=reactio
said Galileo

No, it would rhyme nicely, but it actually was Isaac Newton.

So mounting speakers on opposing sides of a cab will cancel out that part of the reactio which goes into the wood of your enclosure.
You could build a single box with two speaker units, or you could even build two cabs in such a way that they can be bolted against each other firmly, if you want to "impulse-compensate". And hey, presto, if you ever move, you'd have two subs that can be used individually.

But back to the main topic of driver choice ...
If you go here http://www.lansingheritage.org/image...2245/page2.jpg
you will read Vd is 1230 cubic cm or 1.23 litres. This volume is the max amount of air that 2245H can move. Vd simply is Sd * Xmax

Vd will determine your max SPL for any bass frequency. If you go down one octave @ that same SPL, your required Vd increases 4x.
If you want a certain max. level I would simply take the max SPL that your E145 pair delivers at 80 Hz.
==> needed SPL in your new subwoofer is already defined in some way.

(1) From E145 SPL, you could go and calculate the needed Vd (formula somewhere, for instance in Richard Small's Large Signal analysis paper) for 80Hz. Take the calculated value times 2 if your subwoofer uses only one driver to support two E145s. But it's much easier if you don't care for absolute SPL, see 2. below.

2) You decide how deep you want your bass, say 20 Hz.
Assume X/O of your E145 pair is at 80Hz. Then at 40Hz, you would need 4x, at 20 Hz 16-times the Vd of two E145 drivers.
This link http://www.jblproservice.com/pdf/thi...parameters.pdf shows that a pair of E145 will offer Vd of 1.28 litres, and their max SPL at 80Hz fully utilizing 1.28 liters does not to be calculated. But sure is that for the same SPL at 20 Hz, you will need 20.5 litres of air moving capability. So 17 units of 2245H.

The above assumes closed box arrangement. Your E145 will not increase it's capability a lot @ 80 Hz if vented the way you have (low tuning).
Your 2245H @ 20 Hz would. Just assuming your port gain is 6 dB at 20Hz, you are down to about 4 drivers from 17.

==> for single driver subwoofer, there is no way around the Aurasound or similar large-excursion units, if you would like to maintain E145 capabilities all the way down to 20 Hz.

That does not automatically mean the Aurosound combines "musically" (thread title) with your super-low mass E145 units. And the last sentence is not there to infer that it doesn't. I simply have never tried it myself.
Try to find out and be sure i stay tuned as to your findings. Great work so far !

Ralph

[Dr.db]

Thanks a lot for taking the time

Getting real subs that could mate the E-145´s spl would be ridiculous, I have to agree.
I would use the subs for average listening situations with moderate to high listening levels. If I want to go real crazy about it, I´d level the subs a little down or just leave them off...