Woofers for a 3,5-way system

[Dr.db]

Hi,

I was thinking of a 3,5-way speaker kind of similar to the Everests, but smaller and with available parts.

The following components came to my mind:
> 10khz - 2405
> 800hz - 2441 on yuichi-horn
< 800hz - LE14H (woofer 1)
< 100hz - LE14H (woofer 2)
- Electronic 4-way crossover

I´m not shure about the woofers yet.
I´d like them to perform similar to the 2234h in the 4435-monitor. Good sensitivity in the midrange and linear bass response without the need of equalizing. But two 15"s are way too big, that´s why I´m looking at the 14"-woofers.

But which modell in specific would you choose?
I believe LE14H-1 and LE14H-3 have a low sensitivity and plenty of bass, not really suitable as a helper-woofer setup!? The LE-14H-4 might be a better candidate, as the cone is lighter.... But are they available?
Is the difference in the LE14H -1, -3, -4 just in the cone-weight due to different amounts of aquaplas applied? DO voicecoils, suspensions and motor remain the same?
The 1400nd looks very interesting as well. But hard to find as well...
I´m not stuck with JBL, if there´s a more suitable woofer available.

What are your thoughts?
Is this a reasonable concept anyway? Which woofers would you use?

[speakerdave]

I would suggest making every effort to put together two pairs of 1400nd's, since they are the only 14 designed to be used in pairs. Guido may still have access to 1400nd cone kits that can be installed in 1400pro frames, which may become available from tired and retired SR speakers they were used in.

In the early stages of Project May we floated the idea of using 2235's in an MTM type arrangement. GT was adamant that it would not work because that woofer is "too linear." That is, used in pairs they would create a fat bottom--why the culminating double 223x design used the 2234. The other 14's are similarly, "too linear," IMO, for the configuration you contemplate.

If you must use four of one of the other 14's, the LE14-3 would be the most likely to succeed, I think. You might experiment with using staggered tunings as in the M9500. And/or putting one woofer on each side in a sealed enclosure, is an idea that comes to mind here, though I have never tried that or really analyzed it.

One final option would be to make it a four-way, the pairs of woofers working entirely in the acoustic coupling zone and crossing the 2441 in higher on a smaller horn.

[Earl K]

Building ( somewhat ) on what Dave said, but using some numbers to make the case.

Search out transducers ( from any manufacturer ) whose EBP figure comes in between 90 & 95 .
- The 2234 is 92. ( 23 / .25 )
- That figure is easily calculated by dividing the woofers Qes figure into the Fs .


A fun game ( for number wonks ) is to follow JBL's own progressive tweaking ( to consumer feedback? ) of their twin fifteen product DD65000-DD67000.
- One can see that they adjusted the woofers EBP numbers of the 3 1501AL woofers utilized in the 3 variants .

( From observation ), using twin woofers having a number above 100 and a listener is likely going to think the product is bass light / conversely, using twin woofers with EBPs below 90 and the product will likely garner bass heavy/bloated comments ( and mid-bass-mids deficient ).

JBL's last E2 "adjustment" brought the twin woofers back into the 4435s sweet-spot, with a new EBP number of 94
( for the 1501AL-2.



PS; the 12" 2214H has an EBP number of 92.

[pos]

The LE-14H-4 might be a better candidate, as the cone is lighter....

It is!
http://www.audioheritage.org/vbullet...l=1#post215472

[Dr.db]

Very constructive comments, thanks a lot.

@Dave:
Have you listened to a double-1400nd system? How would you compare the bass-repdoduction compared to a 2235 for example?
Do they deliver the same freq.-extension? Which has more snap and the better midrange?

Could you explain your idea of the 4-way with different words please, I don´t really get it.

@Earl:
Thanks for the backround-informations.
Btw, I´ve owned a 2214h once. A good woofer for a 2-way, nothing wrong with it. But I never really fell in love with it, as it just sounded ordinary e.g. unspecial.

@Pos:
Great simulation, looks very promising. Have you ever had the chance to listen to the LE14H-4 and proof that theory?
I think it was essentially used in the S4600 which only sold in japan!? The japanese market anticipates a rather thin or lean bass reproduction due to their smaller rooms with lots of bass-gain... So I´d expect the LE14h-4 to be suitable...

[speakerdave]

I've listened to double 1400nd's extensively, but never double 2235's, so I cannot compare. Joe Nelis has them now and also has 4355's, so he may chime in here. I would characterize them as accurate and articulate really very good woofers and may eventually feel I need some E2's to be as happy or better, though I am holding off on that for now. I can say that in my small E2 experience I thought that midrange to be better.

By four-way I mean put a midrange between the woofers and treble horn, 300 to 1200. In that layout the midrange is taken out of the woofers, so the question of low bass/midrange balance when doubling up linear woofers is mooted.

I would add that in general I think when using legacy woofers--that is anything prior chronologically or technically to the hyper-engineered uni-frame 1400nd, 150xAl, 2216, and also 1501fe, and TAD 1102 and 1601c--for the lowbass into midrange the benefits of bandwidth limiting our still in effect. That is, the liabilities of the added complexity of three and four-way systems are more nearly worthwhile. Even with those woofers doubling up and digital eq are employed to reach the lows the 2231/2235/2245 get to, not that there's anything wrong with that.

(I've never heard the LE14-4, so I can't speak to that.)

[pos]

Have you ever had the chance to listen to the LE14H-4 and proof that theory?

Nope...

[Dr.db]

That´s a lot of good input.

I got the 2123´s here and it still remains as one of my favorite drivers. I have tried them between 350-1200hz running with a 2350 horn with 2441 on top. But it doesn´t match up nicely, I think this must be because of different dispersion characteristics. The 2350 is 90° horizontal and the 10" is probably a lot wider at 1200hz...
Ian told me before, that it´s probably much easier to match a 15" cone with a 90°-horn because of similar dispersions at aprox. 800hz.
But running a heavy cone up that high sometimes sounds a little muddy. That´s why I´m thinking of this concept here. Having a helper woofer below 100hz makes it possible to use a lighter, snappier 15" or 14" cone up to the horn.

Regarding these 1400nd woofers...
Sounds like these are very well engineered products. I´ve studied some older threads and it seems the M9500 and S9500 which made use of the 1400nd in doubles where exclusivly tuned for the japanese market. They included the room-gain from small room when tuning these enclosure´s and woofers. So I´m afraid they may won´t work in my listening room, as I will have huge bass-traps (aprox 8m² of absorbent surface) in a 30m²-room. I cannot count on massive room-gain, I need the system to be rather linear to 30hz.

[Ian Mackenzie]

Hi,

I was thinking of a 3,5-way speaker kind of similar to the Everests, but smaller and with available parts.

The following components came to my mind:
> 10khz - 2405
> 800hz - 2441 on yuichi-horn
< 800hz - LE14H (woofer 1)
< 100hz - LE14H (woofer 2)
- Electronic 4-way crossover

I´m not shure about the woofers yet.
I´d like them to perform similar to the 2234h in the 4435-monitor. Good sensitivity in the midrange and linear bass response without the need of equalizing. But two 15"s are way too big, that´s why I´m looking at the 14"-woofers.

But which modell in specific would you choose?
I believe LE14H-1 and LE14H-3 have a low sensitivity and plenty of bass, not really suitable as a helper-woofer setup!? The LE-14H-4 might be a better candidate, as the cone is lighter.... But are they available?
Is the difference in the LE14H -1, -3, -4 just in the cone-weight due to different amounts of aquaplas applied? DO voicecoils, suspensions and motor remain the same?
The 1400nd looks very interesting as well. But hard to find as well...
I´m not stuck with JBL, if there´s a more suitable woofer available.

What are your thoughts?
Is this a reasonable concept anyway? Which woofers would you use?

I dont think an Everest in a smaller design with available drivers is a reality?

If you don't have the room you don't have the room so why screw and compromise an idea?

These augmented bass helper systems are difficult to get right for a start.

If you can't clone exactly don't clone.

So the idea is extended low distortion bass and above average sensitivity.

What I would do is keep it really simple and salvage the most important aspects of the woofers you can easily acquire and improvise.

Availability of appropriate woofer drivers is the most controlling influence on your design.

I would start off with a single 2234H and add a sub under it in a separate enclosure to flesh out the bass.

If you can afford it get a 2216-nd1 or consider an E145.

Have a look at Rob's sub he designed to replace the 2235 sub. I think its a 2266 woofer in 2.5 cu ft.3

That driver with the right tuning will kill.

The smaller enclosure of the single 2234H gives flexibility of the cabinet placement and adding the horn.

The other way is this idea of a V profile baffle. That approach has been around for years and no ones complaining.

https://cdn.shopify.com/s/files/1/14...71749891643682

[Dr.db]

As all of the 14"-woofers are hard to get, this concept probably isn´t reality...
Availability is a problem, but member edgewound can rebuild LE14H-woofers up to specs so these ones should be obtainable.

If I use a higher sensitivity woofer like 2234 or even e145, I need some kind of subbass reinforcement. Either a subwoofer or a helper woofer....
You indicated that an augmentet bass helper system is difficult to tune right, I absolutly believe you. But is it easier to seamlessly integrate a subwoofer?
Subwoofers usually are located away from the mains, so it is very likely to be out of phase. A helper-woofer is placed right beside the lowmid-woofer...
Subwoofers have a 2nd or even 4th order lowpass somewhere around 50hz introducing unwanted group-delay. A helper-woofer with a 1st order lowpass at 100hz would have less group-delay...
A helper-woofer is an identical woofer as the lowmid-woofer, so the mutual coupling should work much better than with a different woofer like it is used in a sub.
I have no experience with augmented bass helper systems, but in theory they seem to be the smarter solution compared to subs!?

The V-profile baffle of the Augspurgers makes sense, but I don´t like the looks.
I still have a pair E145 in my shelves. Great sounding lowmid, but in the need for subs...

[Ian Mackenzie]

In your first post system size was the over arching consideration.

Hence l suggested an effective solution

So you have to make practice decisions.

Looking more closely at the augmented woofer what actually happens is both woofers add below around 100 hertz to give hopefully a flat response under the environment you plan to use.

What you need to start off with is an over damped tuning or falling response of a single woofer. The 2234 and other 96 dB woofers are more user friendly for this approach than the LE14H.

In the passive crossover world that means around 20 mH of series inductors to form a 6 dB low pass filter

The series resistance of about 1 ohm on the helper woofer causes a loss and at the same time interaction with the bass response because QTs is raise. So the engineer adjusts the filter and box tuning empirically to arrive at an optimum system response.

You are going active. That is a game changer.

With some careful adjustment with a dsp plate amp you can EQ and get a respectable result or you might not.
Otherwise you might end up with a very lean bass with the augmented woofer approach.

The idea of a separate sub was once difficult to integrate.
But with dsp plate amp power is now in the hands of the user to dial in delay, EQ

The benefit is the latter is a smaller system and in practical terms more forgiving of the diy builder to implement.

Many pro studio monitors with a single 15 inch woofer are built on the concept of a sub today

[Ian Mackenzie]

As all of the 14"-woofers are hard to get, this concept probably isn´t reality...
Availability is a problem, but member edgewound can rebuild LE14H-woofers up to specs so these ones should be obtainable.

If I use a higher sensitivity woofer like 2234 or even e145, I need some kind of subbass reinforcement. Either a subwoofer or a helper woofer....
..

At a simplified level a 96 dB woofer brings you into the realm of an idealistic system.
We are talking about efficiency, dynamic range, lower power compression and lower distortion.
In comparison a lower efficiency woofer needs much more power and it tends to sound less real.

However, if you want more bass extension and lower distortion then you are up for the helper woofer and double the realestate. To make it work the way Jbl did you need to stick with the 2234. I have not looked at the E145. That means a big box.

The LE14 is a less efficient driver designed for a compact system with reasonable bass extension.
It’s a compromise but it’s okay if you can live with that.

I personally think a medium to high sensitivity woofer gives a good deck of cards in the diy space if you are not wanting to pursue a 4 way system.

My suggestion of the sub is a pathway that will give you the efficiency and the bottom end in compact design.
Crossover 60-100 hertz and don’t worry about the theory. You have flexibility with that approach with the sub driver ect.

I realise the helper woofer as a format is cool and easy to get hooked on but in terms of cost, size and complexity ..... there are other approaches to the end goal.

[Dr.db]

Thanks a lot for your extensive answer.

Actually I´m not against a 4-way system, infact I´m totally obsessed with the 10" midwoofers.
But it seems very hard to integrate them reasonable to match up with a big 90° horn.

Two 2234h would be great, but unfortunatelly the enclosure gets too big as you mentioned.

I´m going to use an analog active-crossover, no DSP.
So there´s no way to compensate for the delay of a sub. Otherwhise I would have used the E-145 as midwoofers augmented by a 2245 or similar. But then again, a single woofer always makes trouble with room-acoustics.

The LE14h is less efficient, true.
But using these in doubles would be a tough competition for a single 15", don´t you think?

[Ian Mackenzie]

I would investigate Speakerdaves Jbl 1400 suggestion if you believe 4 woofer is the only way.

Double LE14s. If you get some graph paper and sketch the response of 2x LE14 at rated sensitivity you will see that after you flatten the bass and use a low pass filter at 150 hertz you are lossing all the benefit of dual woofers in terms of conventional application.

The only net gain will be less distortion in the bass.

They will need at least 3.5 cu ft each

Have you considered a single (new) 2216?

I run them with my 4003’s

Sometimes less is more

http://www.e-hifi.com.au/brands/jbl/...ors/s4700.aspx

[Dr.db]

Double LE14s. If you get some graph paper and sketch the response of 2x LE14 at rated sensitivity you will see that after you flatten the bass and use a low pass filter at 150 hertz you are lossing all the benefit of dual woofers in terms of conventional application.

The only net gain will be less distortion in the bass.

But using 2234 for example this would be the same "problem", wouldn´t it?


I have no experience with the 2216 at all. But in case of a single 15" I would still use my TAD 1603´s...