[hubert]

Hello all,

Apologize for my poor english, school days are far away.
I have Ellis-audio 1801b speakers and a rogers E40a tube integrated amp.
I love both their sound.
The 1801b is a 8ohms speaker with a minimum at 6.2ohms between near 100 to 300hz.
The Rogers is a double push-pull 6l6, 2x40 watts in class A.
My question is:
If I go to build a double-1801b with parallel wiring, sensitivity will increase in +6db and impedance decrease to 4ohms with a minimum at 3.1ohms; Can I go this way without damage for my amp?

Thanks for your help.

[Occam]

Hubert,

Your English is certainly better than my French. Je parle Francais cum une vache....
The Rogers E40a is a modern tube intergrated (Designed by Audio Note UK) and has a 4 ohm tap as well as an 8ohm, so I assume it will drive that impedance without self destructing.
As to the wisdom of driving a dual 1801b (I'm assuming that you intend to build a double 1801b, and not drive 2 sets of 1801b in separate rooms) or how it will sound, I can't offer an opinion. If your intent is to be able to produce higher SPLs, loundness, you might want to talk to Dave about adding a subwoofer to relieve your 1801b of producing the lowest bass octaves, or possibly some other options. Doubling up on drivers, cabinets and crossovers will not give you a louder 1801b, as the imaging, soundstaging, and possibly the tonal characteristics will change drastically.

Regards,
Paul

[hubert]

Occam,

Thanks for your reply; If your knowledge is sufficient, please let me know a little more on impedances matching between speakers and tube amps.

About the project of a double 1801b, this idea came from listening to a simple apertura kalibrator (a two way speaker in 8ohms like the ellis) vs a double kal (a second kalibrator placed on top of the first through a large frame, parallel wired, but probably have you heared something about these stuffs).
The listening results are far better with the double kal, even, and that is astonishing, at moderate levels! I'm almost sure it's the decreased cones displacement that allows this result.

I don't need more spl or 20hz, so a sub or anything else is not my aim. If so, I've in my cellar a couple of audiom 15vx wich are sleeping since a few years beside aktiv-fiter 100w amps; this stuff is very good in a symetrical reflex/sealed box to get a powerfull 25hz but because of a 24db roll-of (12db from box loading and 12db from aktiv filter) the phase matching is very difficult to get with the main speakers. And...my room isn't wide and...1801 bass are for me largely enough in spl with most of my CDs.

About the shape, my knowledge is sufficient to get proper image and soundstage related to the acoustical phase of the couple of 1801 drivers, in a framed double box or in a floorstanded version.
Because this project isn't completed in my head, I don't know if I'll really build such a thing; but the idea is for me good enough to think about.
Another technical advantage is the possibility to tune the stuffing and the port differently on the two VB; this will surely smooth the box resonances.

regards
  elsass beer is the best in the world!

[Occam]

Hubert,

I'm somewhat familiar with what you are attempting to do. About 7-10 years ago, a US based publication, 'The Sensible Sound' reccomended stacking an inverted Paradigm floor standing speaker upon another. This worked for a specific model, but not others. I believe this was due to the specific physical layout and crossover topology used in certain models, which by happenstance seemed to work quite well.
I assume this was due to the frequency dependant radiation patterns of the specific speakers, and the fact that the physical spacing of drivers of the resulting stacked combination yeilded an overall combination that worked well.
But you seem quite aware of the complexity of what you are attempting to do, and realize that for optimal results this might require a mounting frame that would allow for variable spacing and non parallel mounting of the speakers. The result might provide a wider 'sweet spot', optimal listening window, or a narrower one....  Or you might find that the spacing between the tweeter and the top of the speaker precludes you from mounting the inverted pair optimally. I simply don't know, but your second post shows a level of sophistication and understanding  that I find reassuring.

If you decide to proceed with this project, I'd like to hear of your results.

Thanks,
Paul

[hubert]

Hello Paul,

Thanks for your last reply, it seems that you too, are aware on problems wich could appear by doubling a speaker.

At first, I must explain why I don't mail with Dave Ellis about this project:
- As the creator of the 1801, I feel a little bothered to submit him a process that, somewhere, is a modification of his creation.
- Technicaly, I'm quite sure that he doesn't approve the decreased impedance of the speaker, a lot of posts about 1801 WTW projects prove it.
- I know his integrity and he will never say me "yes, go on" without having tested this project.
- He don't have time for such kinds of frenzy.
- He needs time for his 3ways.

Secondly, if I decide to proceed with this project, I'll post the review only with Ellis permission ( except for you Paul and for my loving pem and raoul ) and if results aren't what I whished, fault will only be mine and nobody else.

However, as I said you, I believe that this project can be viable: prove is the double Kal vs the kalibrator (in a side note, the 1801 is much better than these two on all the criterions).

Now, if you or others are interested on this project, please let me know your minds about what I write here:

THE problem is the radiation pattern. Radiation pattern is nothingelse than different energys (spl) on different frequencys, in relationship with time delays.
Two 1801 are two perfectly identical speakers with same radiation pattern. With one couple of 1801, the target is obviously not to get the same radiation pattern than the single 1801 but a perfectly symetrical radiation pattern.
If the tweeters are both verticaly placed very near one to the other, the woofers in the same place than the single 1801 in a horizontal mirror image and if the virtual line separeting the tweters is at the same height than the common height of the listener ears, you will get a virtual point source; it's to say that all the energy of all the frequencys of the two drivers couples add simultaneously at the same time; if so, no slanted baffle needed, and no different deepness between the couples of drivers needed; in this way you can build a one piece box. The only problem could be the floorbounces energy, different from the woofer at the bottom than this at the top; but this problem exist with the single 1801 too and tuning the ports differently from one VB to the other could, IMO, reduce this effect.

Now, if the virtual separeting horizontal line between the two couples of drivers aren't at the height of your ears, you should need to build two separeted boxs with at least, or the topbox slanted, or the bottom deeper placed; in this way, diffraction problems could appear and should be treated.
So, one piece box is for me the best and most simple way.

Regards
  elsass beer is the best in the world

[hubert]

Hello Paul and all,

About my "doubling the 1801" project, I mailed with the wellknown NL Tony Gee (humblehomemadehifi) and Dave Ellis.
Regarding all the technical matters, my project was approved by this two fine gents.
However, I'll not go this way because if it's true that all the frequency range will improve at the same level giving a better global sound, the bass will not improve as if I'll use a real woofer (the present little 1801 lack).
At least, this project let me (you) know that if the line separating the two couples of drivers is in-axis the ears, ANY speaker can be doubled, taking care to the resulting impedance.

  elsass beer is the best in the world (it's not true, but white wines, YES)