conjuring deep bass from E145 in a huge enclosure

[mech986]

What's the difference between the E145 and K145 or K140? I'm not knowledgeable about the MI and Guitar drivers.

Personally, if one was to build a 9 to 12 cu ft box, I would submit that the 2245H or 2241/2242H would be much better drivers for low bass applications.

[johanwholst]

Well, with deep bass I'm referring to 30-35hz in room response.
I really like the sound of e145 as a wide range driver, and in my room it's way easier to place a big cabinet compared to adittional subs.
Been comparing these woofers to 2216nd and I'm actually prefer the e145 even the low end of equalized 2226nd in a M2 cabinet is amazing.
We will see what comes out of this.

[ivica]

After playing with E145 for a while, I concluded that iit s my favorite driver despite lack any significant output under 50hz in my 140L (4.5cuft) test cabinets
Im now contemplating building cabinets at 300L net (10cuft) tuned to 30hz, a bit under the resonance frequency of 35hz. I am using a DSP solution.
Any reasons not to go ahead with this project? Can a cabinet for these drivers ever be too big (wife's opinion not included)?

Hi johanwholst,

If You can accept that E145 driver Vas=427 Lit, then as any of bass box simulation program, You can see that using larger box would give You some improvement, but I would not suggest to tune the box under 40Hz, due to the cone displacement, so in such situation I would suggest to introduce sharp HF filter round 40Hz. May be the better results can be get using your box with the E145 in it, and make another larger box for 18-inch bass driver such as 2242, 2240, 2245, 2269 ...and introduce it as 'sub-woofer'.

regards
ivica

[Dr.db]

I´m on a project with an E-145 right now.
I´ll build 7,5 cubic ft. vented enclosures tuned to about 35-40hz.
There will be pictures and comments on my build in a couple of weeks located here: http://www.audioheritage.org/vbullet...Heritage-Forum

I have compared a 4,5 and 7,5 cubic ft. test-enclosure before.
In the small enclosure there wasn´t much going on below 50hz. In the huge box the E-145 took benefit and reached a little lower. But to put things right; the differences are not huge! But the enclosure size is

My experience told me, when located in the 4,5cubic ft box, it was best tuned to 45-50hz. This made a good output 50hz and up. When tuning this enclosure-size to 40hz, you will suffer a lot of efficiency between 50-80hz which really is noticeable.
The biggest advantage of the 7,5cubic feet enclosure was, that you really could tune the E-145 to 40hz without loosing to much in the midbass. But even in this beast of an enclosure, it is rather reserved in the lower bass.
It´s the nature of the driver, either people like it or leave it.
It has incredible punch, even in the big enclosure, but you will never get it flat to 40hz or lower without EQing.

[Ruediger]

Dr. dB,

can't you get in touch with an electronics guy who can do the measurements? You need a voltmeter, an amperemeter, a freuency generator and maybe a small amplifier. The two meters can be multimeters.

See figure 5 in the 1st Thiele paper on page 184. You need to measure a few points of that curve. The box can be one which you used for testing.

See page 203 in the second Thiele paper, top left. "The speaker is now placed in a vented box ..." This is how you should do the measurements.

Then there come some formulas about how to calculate Vas/Vb.

That's it.

ruediger

[Dr.db]

Hi,


I´ve allready started with the final enclosure, so there´s no way back to a smaller one.
Unfortunatelly I have no electrician around here...

[Loud & Clear]

I have a pair of JBL Cabaret 4628b's and they'll make the trip down to 30-35 cycles...

[more10]

If you don't care about playing loud, maybe a closed cabinet with Q=0.5 and a Linkwitz transform?

[toddalin]

If you have enough volume to play with, you can increase the bass by putting a 100 watt, non-inductive resistor in series with the woofer. This works because the E-145 has an impedience of about 60 ohms at 45 Hz, but only about 8 ohms above 100 Hz.

With the resistor the decrease in volume is about 0.5 dB at 45 Hz. But the decrease above 100 Hz is about 3 dB. So, relative to the overall sound, when you turn up the volume to compensate for the difference in volume of adding the resistor, you increase the bass at 45 Hz (and around it) by about 2.5 dB, and will hear a difference in the deep bass.

[mech986]

Todd, what is the resistance of that resistor, you only stated the wattage and non-inductive character.

[toddalin]

My bad..., 8 ohms. More ohms will give you more bass but remove more overall volume.

[Ruediger]

Todd,

if you place a resistor in series with the bass, you increase Rg (generator resistance) and thus Qt, and that can make some more Thiele alignments available. So you can calculate these configurations properly.

But rather than putting a resistor in series you can build your crossover with affordable inductors, can built 3rd order filters (having two inductors) and can use affordable cables. The not-so-heavy wires will supply the resistance.

Ruediger