[jrebman]

It's official, we are back up as an active circle, even if we are a bit on the fringe of the mainstream audio world.  At least that's how some people look at it, but if quality of sound is your metric and not percentage of overall audio equipment sales, then we all know why we're here and mainstream or not, probably doesn't bother us.

I'd like to establish the definition of a single, wide-bandwidth driver for the purposes of this circle and ask people with systems that fall outside the scope of this definition to post in a more appropriate circle.

Speaker systems that are relevant for this circle generally have the following characteristics:

a) They typically cover approximately 7 or more octaves of the audio spectrum within approximately a +/- 6 dB range.  Typically something that handles between 40 and 100 Hz on the bottom end and approximately 14k or better on the top end without the use of helper drivers of any kind -- including coaxially mounted tweeters and such.

2) Augmentation at the extremes is acceptable as long as the main driver meets the specs above and the crossovers don't limit the bandpass of the main driver to the point where it is reduced to functioning as a glorified midrange, mid/tweet, or bass/mid driver.  Taking off some load -- roughly an octave or so from the bottom end to get more mileage out of a low power amp, for example is fine.

3) Contour filters are completely acceptable -- whether they be passive or active, line-level or speaker-level, analog or digital.

 4)Of course if you have a bipole or dipole speaker whose drivers meet these requirements, they are fine to discuss here.

With regards to the discussion of ancillary equipment -- amplifiers and such, that is permitted and encouraged, but within the scope of how a particular amp works with a SD speaker.

In other words, please try to keep everything relevant to the world of single driver speakers and stay within these guidelines as best you can.

Of course all the rules about no personal attacks, being civil, and letting people disagree with you without getting your feathers ruffled apply here as they do elsewhere on AC.

Over the next week or two I'll be going through the old threads and moving some to the IGW, but only if they were overtly commercial, flame wars, or not relevant to the topic here.

So, that should be it and now that the formal rules and regs have been established, let's all have a good time and share the passion we have for this hobby.

Welcome again,

Jim

[Len_Dreyer]

Hey Jim, thanks for bringing this circle back to life.

Len

[chadh]

Jim,

Thanks so much for resurrecting this circle.

Just a quick question of clarification, though.  My setup currently satisfies the definition of a single driver system.  But I'm considering adding stereo subs to the system specifically to relieve the wide-band drivers in my main speakers from the duties of producing the lowest octaves.  If I understand your outline from above, queries I have will be acceptable in this circle only if I choose to run my main speakers full range.  But if I choose to introduce a high pass filter at around 100Hz, then my queries should be directed elsewhere.  Is that right?

Chad

[floobydust]

 Hi Jim,

 Nice to see you back.... hope you've had a chance to work on the Gamma-1 (I've built 5 so far). While reading thru the qualifications for a full-range driver setup, I generally agree but would implement augmented support for the extreme octaves differently, specifically on the bottom.

 For better single-driver systems, I still feel that the last 1-1/2 to two octaves are the most difficult to produce and will at some point require augmentation. If I am going to augment with a sub, it will be powered and it will have a dedicated crossover. I will also attempt to use the lowest crossover frequency to maximize the single-driver system. However, once I arrive at a satisfactory crossover point, I would also provide a simple 6dB/octave passive roll-off for the single driver amplifier input. If I'm using a dedicated sub to provide that lower support, I'd rather save those extra few watts from a low-power SET for some dynamic extension (or headroom) in it's active range.

 Regards, KM

[planet10]

Just a quick question of clarification, though.  My setup currently satisfies the definition of a single driver system.  But I'm considering adding stereo subs to the system specifically to relieve the wide-band drivers in my main speakers from the duties of producing the lowest octaves.  If I understand your outline from above, queries I have will be acceptable in this circle only if I choose to run my main speakers full range.  But if I choose to introduce a high pass filter at around 100Hz, then my queries should be directed elsewhere.  Is that right?

That one condition eliminates FAST systems which are traditionally considered single driver systems. I think that that is a serious shortcoming of the definition.

dave

[Mr Content]

Cool, I have been a single driver guy for several years now

Mr C

[Bob_Brines]

I find the prohibition on helper drivers to be excessively restrictive.

On the low end, most small drivers (4" and smaller) cannot produce any real bass unless corner loaded or mounted in huge horns. The current trend is toward small drivers OB mounted. The physics of a OB of what is normally considered large is going to cut off ~300Hz give or take and is therefore prohibited here.

On the high end, while a full-range driver may produce 20kHz on axis, most 6"and larger drivers can't get to 10kHz 15* off axis. Crossing in a tweeter first order works, sort of, but there is always serious interference between the two drivers that can go rather low. A well implemented 2nd order or higher XO high enough to keep the phase shift out of the telephone band  makes for much better implementation. How many drivers have nasty peaks ~7kHz that could be easily tamed with a XO at that point?

The prohibition on filters implies that BSC filters and zobels to tame a rising response are out. You didn't specifically say so, but that can certainly be implied.

A more reasonable definition of a wide-range implementation is the main driver must produce at least the 300-3000Hz band without cross-overs in that band.  Otherwise, too many good speakers cannot be discussed here.

Bob

[JohnR]

A more reasonable definition of a wide-range implementation is the main driver must produce at least the 300-3000Hz band without cross-overs in that band.

C'mon, that definition just makes this into the three-way loudspeaker circle 

[Wind Chaser]

Re: Welcome to the new Single Driver, Wide-bandwidth speaker circle

Doesn't a single driver mean just one driver?

[ohenry]

...The current trend is toward small drivers OB mounted. The physics of a OB of what is normally considered large is going to cut off ~300Hz give or take and is therefore prohibited here...

The open baffle circle can handle those.

Screw it Jim, RUN!!!   

[JLM]

An vintage definition of single driver speakers is one that covers 80 - 8,000 Hz. 

IMO zobels and/or baffle step circuits are OK as are any form of equalization. 

Designs that use multiple drivers (of the same design) or crossovers can apply elsewhere.  OTOH, adding a subwoofer doesn't affect the single driver speaker design, so my vote would be to allow them into the discussion.

[jrebman]

Well, good morning.

Yes, there may be some *minor* tweaking to the definition -- mostly as it pertains to bass augmentation.  No compromises on the high end though as really then we're just talking about 2 or 3 ways with a super-mid.  I'll do some thinking and some research on some of the better drivers and see what actually pans out.

I inadvertently left out any statement about contouring filters, and of course they should be fine, whether active or passive, line level or speaker level, analog or digital.  contour filters do not effect the bandwidth.

This is how I'm going to think about it -- if you remove your bass and treble augmentation, is it still satisfying to listen to?

JLM, I'm not interested in the vintage definition -- I am familiar with it and don't think it produces a satisfying listening experience as defined.

Bob, as Henry said, there is an OB circle, and sorry, but the telephone range -- also something I am quite familiar with -- is not something I want to listen to, but I do agree, as stated above, that contour filters are acceptable.  However, I'll state my preference or prejudice, however you want to look at it, for line level contour filters as opposed to speaker level.  Keeping as much stuff out of the path between the amp and speaker is, IMO, something to strive for. PLLC s aren't perfect, but they are what I prefer.

Kevin, yes, about 90% done with the Gamma DAC -- just forgot to order a couple caps and one of the power manager chips but am saving up for a larger order before I get them.

Well, thanks all for chiming in, but the bottom line here is does your speaker sound satisfying with no augmentation at the extremes?  That's the real challenge in both driver and speaker design that when realized, results in a very special sound with no integration issues.

I do also want to say a bit aboue about efficiency and sensitivity -- assuming most folks know the difference -- and that is that was deliberately left out of the definition as there are some very sensitive/efficient SD designs, and some that are not so.  Yes, again, I prefer the more sensitive/efficient designs because they allow me to use the kind of amplifiers I prefer, but that's my thing.  I don't care if your SD speaker is 84 dB with a roller coaster phase/impedance curve and needs a 400 watt digital amp to make it go, as long as it falls within the scope of the definition.

-- Jim

[rajacat]

What about bipole single driver designs like Omega Bipoles? Do they fit the single driver definition of this circle? http://www.omegaloudspeakers.com/products/specialapps

-Roy

[jrebman]

Roy,

Yes, it's already in the definition and has been since I originally wrote it.

-- Jim

[rajacat]

Roy,

Yes, it's already in the definition and has been since I originally wrote it.

-- Jim

Jim,

Whoops! It was a spur of the moment reply. I should have gone back and read the beginning of the thread.

-Roy

[JLM]

Jim,

Please elaborate on why 80 - 8,000 Hz (over 6.5 octaves) doesn't provide a satisfying listening experience to you.  Are you after a higher frequency "balance"?  (I was just looking for a minimal entry point, not something highly desirably).

[planet10]

This is how I'm going to think about it -- if you remove your bass and treble augmentation, is it still satisfying to listen to?

That is similar to my definition... the main driver needs to be able to supply a satisfying musical experience all on its own

dave

[DaveC113]

A more reasonable definition of a wide-range implementation is the main driver must produce at least the 300-3000Hz band without cross-overs in that band.

C'mon, that definition just makes this into the three-way loudspeaker circle 

Agreed. I have no interest in a 300-3000 Hz driver running ob.

I also agree w/ KM... rolling off the single driver in the last 2 octaves should fit the definition too.

Hope you're doing well Jim. 

[jrebman]

Ok folks, I've updated the guidelines and hopefully they are a bit more clear and slightly broader in scope without opening too big a loophole .

Dave, glad to see you here -- haven't heard much from you lately.  Guessin the new job is keeping you pretty busy.

-- Jim

[chadh]

Jim,

the update to the guidelines are greatly appreciated.  Thanks.  I'm looking forward to absorbing as much info as possible in this circle. 

Chad