[Michael V]

dyohn -

Any idea which Selenium woofer that is?  If it's the 15PW3 listed on Parts Express, it's certainly within most DIYers' budgets.  They're only $65 each, when you order 4+.

Most likely their rated sensitivity of 98db is "optimistic", hence the 2 woofers per side employed here to reach a 98db system sensitivity.

On a related note, what about using 2 of a Selenium/Alpha 15/etc. in series, along with Graham's T-bass boost circuit?  I'm just wondering if you could end up with a SET-friendly impedance that way.

Regards,
Mike

[Graham Maynard]

Hi Mike,

The T-bass needs a low impedance source to work best, and as far as I know most SETs tend to have an output impedance similar to the optimum matched LS impedance;  this being why higher Q drivers produce higher LF sound levels when driven by a SET amplifier.

Better to keep SETs for the main driver only and use SS for LF, whereupon sensitivity does not remain a problem.

Cheers ...... Graham.

[dyohn]

It certainly looks like a 15Pw3 to me, but no I am not certain.  I can ask if you like.  HERE's the manufacturer's spec sheet for the Selenium 15PW3.

[Dmason]

Go far enuff back and they were all OB speakers. Later, they found that feedback loops were also useful in controlling cone behavior. The old Webster PP units in the big Hammond organs had 32+db but man could they play loud, and the old cones were perfectly in control. Now we have switching amplifiers with high damping factors that are very well suited for this type of speaker.

"everything old is new again.."   

I have thought for awhile that the ga ga response to some of these new OB recipes at the audio shows is moreso a reaction to the actual OB gestalt primarily, made and written about by high-dog monkey coffin listeners, than to any particular combination of speaker driver and/or crossover.

I still find that no crossover is the best crossover, at least between say, 150Hz-8kHz, and no alignment is the best one. At this point, boxed speakers are all starting to sound pretty weird to me, so I  applaud their high minded invention.

As per the mega pricetag, it is a consumer society, and freemarket system... caveat emptor; .. for low level listening however, I would absolutely put my $20.00 Magnavox stereo FM radio up against that monster; Twenty bucks yes, BUT it employs a single ended tube amp, and open baffle speakers . I think what Richard was getting at is that the OB gestalt doesn't require the layout that an array of SEAS Excels would.    

[guest46813]

My eyesight is probably not that good so I posted in the wrong thread. Now cut and paste.

Hi

This is my 1st post on AC. A gentleman told me there is a thread on my speakers.

I agree that all planar or OB speakers share a common open sound signature. OB has been around a long time, the Western Electric Shearer speaker has field coil woofers on an open baffle. The open sound is what I like, having owned and modded many large Maggies and Quad ESL (double or triple stacked)

I do think that the quality of the drivers will also play a role in the sound signature, particularly the mid. That is what Jean Hiraga always said, and actually his magazine and la maison de l'audiophile was what brought me into audio in the 70s. The 12NDA was chosen because it does sound in some areas similar to the field coil Supravox

The asking price relates to this specific pair, which uses premium exotic figured veneer cut from a single tree for matching grains between the 2 speakers, bases and crossover boxes. The speakers front and back, the base and crossover boxes require quite a bit of acreage. You could buy quiet a few 3G Iphones for the cost of the veneer material. Unlike the Maggie and Quad planars I have owned before, what I have in mind for our speakers is the raw look and feel of high end furniture made from wood. There are some 7 layers of finishes applied, rubbed and waxed by hand with Renaissance wax which is used by NY MOMA and british museums.

Pricing is also reflective of the components used. For this pair, we have Siemens film in oil caps, Western Electric polyprop caps, large value Clarity SA caps, Mills MRA, shotgun MIL-spec silver/OFC wires (the same wire used in your stealth fighter jet -aerospace is my other passion), etc. The Siemens and WE caps are in very limited supply so we will be using different oil caps once supply run out.

Depending on the chosen wood finish and the other components, the price will change. Normally, I would not recommend exotic wood. Finding the right lot and matching the grains can be a lot of work.

I do agree that if you can design and build your own speakers, that is the most cost effective path and it also an excellent learning path.

Thanks for the interesting discussions. Regards

[Dmason]

Impressively rendered!! This is one machine I would love to see, hear, and touch. Nothing like good wood. Congratulations on your concept and design, best wishes for a great entre, and a continued conversion to "the dark side." What no one has said is that there is little doubt your speaker design will surely STUN the audience, wherever they are.

[guest46813]

Thank you for the very kind words of encouragement. Best regards.

[scorpion]

I don't doubt that the 'K&Q Sound Genesis Model 1' will sound terrific but an explanation of how 98 dB/1 m and I suppose 1 Watt is achieved at 36 Hz would be appreciated. Since that evidently occupies many reader's mind.

/Erling

[guest46813]

Hi erling,

You are very correct. At 36Hz or even 50hz, you will need much more than 1 w.

Separate sensitivityfor mid and bass would be more appropriate as the impedance are not the same. The speaker is a biamped design although the crossover is passive.

There are always pitfalls in drafting an ad without becoming an engineering paper.

Regards

[iON]

I like the looks of your speaker Quoc!

Too bad I didn't see the ad earlier since I actually was in NJ last week. It would have been interresting to audition them. Again, nice looking set of speakers. I wish you good luck on your forthcoming ventures.

Sincerely,

ion,
Sweden

[Rapt]

quoc

           Very nice looking speakers, where might one look to read reviews etc do you have a web page, I would be very interested in following the progress.

                                                                    Thanks.. and I wish you the best in your endevour!

[Angaria]

Has anyone heard the seleniums in comparison to the acoustic elegance open baffle/lambda woofers?

[guest46813]

The Acoustic Elegance/Lambdas are in a different class than the Selenium in my view, especially if your design cut off the woofers at higher frequencies. I particularly take notice of the AE 15-inch midbass driver there which seems to have a very smooth roll off.

Currently in my design, the woofers are mainly bass augmenters to the mid driver. It was a decision between the Selenium, B&C and Beyma woofers. To an earlier question, in the end I chose the 15PW3 as in the bass, it has some pluses over more costly woofers.

The overall signature from the speakers come largely from the 12NDA and DE250. A high quality mid driver and tweeter plus high quality passive crossovers are the areas where I decided to emphasize.

I also like the Tone Tubby 12 Alnico: it is a "colored" driver but then my 18th century Collin-Mezin violin is colored as well. Beautiful strong tones, music with a soul.

In many ways, I always like the idea of a full range or wide band driver. One of the speaker I built a few years back is a 3 way horn system, a field coil Supravox feeding a horn running wide band between 300Hz to 7Khz, with 15-inch bass corner horns at the very bottom and a tweeter horn on top. A friend who lives near by wrote a review of it on an AA post a few years ago; he was commenting on SET with classical orchestral music.

[Angaria]

Thanks for the reply quoc - I'm really impressed with the extent of your search for a great combination of drivers.

[Duke]

Quoc, intersting design.  Back in my "civilian" DIY days I tried to do a passive fullrange dipole, but had to give up so much efficiency to match the passively equalized bass that I went on to other things.  In your passive yet equalized approach, it looks like you have found the solution that eluded me.  I think your combination of SET-friendly top end plus decent bass extension in a dipolar format is quite attractive.

How do you level-match between the relatively power-hungry bass section and the high efficiency upper-frequency section?

Good luck with your project.  It looks like a lot of creativity and experience and work went into it, and I hope the marketplace rewards your efforts.

Duke

[arthurs]

Welcome Quoc!  I was curious if you'd find your way over here for this discussion, thanks for sharing your thoughts.

Please review Industry Participant guidelines here http://www.audiocircle.com/index.php?topic=41871.0 and ensure you have the proper signature.

Enjoy!  I look forward to reading more about your speaker offerings!

[Magnetar]

Those look sorta like a copy what I built.



So you actually found a mid woofer better than an SRO?

[Telstar]

Quoc, intersting design.  Back in my "civilian" DIY days I tried to do a passive fullrange dipole, but had to give up so much efficiency to match the passively equalized bass that I went on to other things.  In your passive yet equalized approach, it looks like you have found the solution that eluded me.  I think your combination of SET-friendly top end plus decent bass extension in a dipolar format is quite attractive.

How do you level-match between the relatively power-hungry bass section and the high efficiency upper-frequency section?

I second this question, since I do not want to go active.