How much can you add to a single driver design before risking its unique qualities?

[VanJerry]

Some of us who come here to seek the full range single driver experience have only read about it's virtues: The simplicity and directness of one driver untouched by a crossover and presenting to the listener sound from a single point in space. Even the enclosure itself may be dispensed with.

You can anticipate magic.

Just put a driver in a box... or not. And you are ready to experience those unique qualities.

For many, it's just that simple.

And once experienced, there are so many directions to pursue: To have more of what you like and have less of what you don't. All manner of things can be added, changed or taken away until... it is quite legitimate to arrive at something that is quite different from a single driver speaker - yet even closer to the ideal for that DIYer.

All of these many ways and preferences are documented and discussed in this forum. It is a goldmine of possibilities and information.

But now that there is so much choice, it can be difficult for the uninitiated - especially for those who came to build for themselves an opportunity to hear what it's all about.

Of course you could just start with something very, very basic. But, if that choice is not made quickly enough, with any amount of further reading one can find themselves drawn by many subtly sophisticated options. And suddenly, you realize, it may be difficult to tell which retain that original single driver quality and which represent valid trade-offs for other benefits.

There are resisters and condensers and additional drivers. Horns, bipoles, and omni's. Notch filters, supertweeters, baffle step corrections, dual widebands, and augmenting woofers crossed at 500 Hz...

Which are necessary or benign to the single driver experience?
Which are variations offering very similar qualities to this experience?
Which will result in obvious or perhaps subtle but very real trade-offs leaving the builder perhaps happier but bypassing the single driver experience?

Just how much can you add to a full range single driver design before risking its unique qualities?

[AndrewT]

Hi,
have you looked at Nelson Pass' horn loaded full range drivers?
Or thought about the dual horn loading (front & rear horns) that Tannoy use for their 15inch driver, with a third horn for the coaxial treble driver. See the Tannoy Westminster Royal, or the Autograph (older) single back loaded horn version.

[hm]

"Just how much can you add to a full range single driver design before risking its unique qualities?"

a 2 driver indirect with distance less than the distance of your ears in a double horn like my KORNETT and SAXOPHON,

more soundstage more bass, no low impedanz peak,
half size of a single driver solution:

http://www.audiovoice-acoustics.com/...read.php?t=174

or on my HP "about what"

[VanJerry]

Originally posted by AndrewT
Hi,
have you looked at Nelson Pass' horn loaded full range drivers?
Or thought about the dual horn loading (front & rear horns) that Tannoy use for their 15inch driver, with a third horn for the coaxial treble driver. See the Tannoy Westminster Royal, or the Autograph (older) single back loaded horn version.

I'm sorry AndrewT, I failed to specify that what I'm trying to do is create a kind of guide on behalf of all newbies whatever their personal tastes might be to the typical add-ons and variations being used in full range these days.

My personal stake in this is to get a better understanding of the suggestions I'm getting myself, for instance, from my own thread on Low level body/weight presence wanted...

You see, I can research particulars such as yours and I thank you for them. But I find it takes a bit of savvy I'm having a hard time keeping up with to know if or how much many of these suggestions are going to take me away from that single point source, crossover-free listening experience that I myself am interested in.

For example, I've read a few posts about how a crossover is not as big a deal if it happens away from the critical range of our hearing. But what is that like compared to no crossover? And how low or high should this be to seem like there's hardly any crossover - if that's possible. I need to know things like this and I thought other's could use this too.

Plus, I think if newbies could get a foundation in this they'd ask better questions and make more effective use of the generous efforts of experienced people such as yourself.

Thank you again,


-jerry

[Scottmoose]

...and [yet] another self-congratulatory advert by Horst for his own (commercial) speakers.

Back OT, how much can you add to a full range single driver design before risking its unique qualities?

Good question, and nobody is likely to give you the same answer. Because it depends on what unique qualities you mean, and how you quantify them; what you value personally, what works in your system & what works in your room.

Purely a personal take: the midband is the critical zone. Bell Labs definition of 200Hz - 4KHz is a decent rough guide. This is where the majority of music lies & you tamper with it at your peril. Having one driver cover all, or the majority of this BW therefore is desireable (providing a reasonable response is maintained of course). Some of these units can also cover the LF & HF sufficiently well to satisfy a large number of people, so get them into a suitable cabinet & they'll probably never feel the need for additional drivers, especially if they can accept large cabinets, or their taste lies in music which is relatively undemanding at the frequency extremes. OTOH, some require more at the extremes & therefore may benefit from the addition of woofers to handle the LF & tweeters to handle the HF. The former does not necessarily have to provide more extension than you may be able to extract from a suitable FR driver alone, but it will (if correctly chosen / designed / whatever) improve transient response & power handling etc. While the latter might theoretically only go up a little higher than an FR unit solo, but will do it with more grace.

Whatever, ideally, you don't want to cross between drivers in this 200Hz - 4KHz telephone band where our hearing is at its best, & preferably an octave or more either side of it to account for the different slopes etc. There is arguably more leeway at the bottom end -if you listen to big orchestral pieces, Pink Floyd etc., then having some high efficiency woofers on hand & crossing a little higher can be a cunning plan as they'll handle all the high-energy stuff & let the wide-band driver, whatever it is, get on with the rest of it. You might loose a little of the supposed purity of 1 driver in the narrow band the woofer covers before handing over, but some will find that a better compromise than having one 'pure' driver distorting something chronic as it tries to keep pace with Nick Mason going ballistic on 'One of these Days...'

Step loss is a different issue. 99.999% of cabinets suffer from it -some are self-correcting, if so designed (high-gain horns, corner-cabinets, bipolar cabinets etc); others require some form of Eq, either via active or passive circuitry. If it's needed, the former is usually the better approach as the passive circuits lower efficiency (higher the better, all other things being equal) & do tend to cause some losses of detail etc. Notch filters can be useful if the driver has a large unwanted spike in its response -again, best cut activlely IMO. Passive's OK in all cases if well designed, but not as good or as refined / accurate as an active or digital adjustment can be.

Dual drivers = OK, so long as you don't mount them both on the front baffle & run them both up high or you'll run into lobing issues. You'll get better power handling in the LF, which is where it really matters, along with other things.

And so on. I'm not interested in following a particular philosophy -it's all tramlining. You go with the compromise that works best for you. Because everything is a compromise. Which suits you, only you know.

[rjbond3rd]

Hi guys, Scott's answer is right on, as always. The only little newbie insight I could add is this: build something quick! You will not get perfection on your first build, so might as well get it out of the way.

On your first few builds, you're really just prototyping to see what your ears like. My starting point was simply popping Fostex drivers into existing boxes, then noodling with box calculators to see what was happening. I think it's critical to get those first few prototypes out of the way -- it's basically a process of elimination to end up with something you want to live with.

One last thought: if you're not handy with wood, don't try to learn on the job. Just get the carpenter or lumber yard to cut the wood, and then you can glue up, pop the driver in there etc. You need to take advantage of whatever shortcuts at first. And buy cheap plywood because chances are, at least in my experience, you /will/ be throwing it away.

[VanJerry]

Thank you Scottmoose,

I appreciate how well your post is on target and I hope it will help set the tone for other responders that follow.

200Hz - 4KHz: You have touched on this and the other issues quite well, but, understanding the peril, could you expand on what might the wiggle room be here in the LF? In terms of trade off, what would people negatively risk experiencing if they were to attempt to take their augmenting woofers up as going up as high as 300 or 400Hz for rock and HT. Could you comment on how much or in what noticeable ways that critically desirable extra bit is likely to contrast with a single FR driver in terms of a deviation from point source? As long as 2 drivers on the same baffle are not both covering HF, is there any benefit to greater or lessor vertical separation distance when using a LF augmenter?

Yes, compromise is key. However with your help and that of others, the hope is it'll be by choice and not as much by surprise

[VanJerry]

Originally posted by rjbond3rd
Hi guys, Scott's answer is right on, as always. The only little newbie insight I could add is this: build something quick! You will not get perfection on your first build, so might as well get it out of the way.

On your first few builds, you're really just prototyping to see what your ears like. My starting point was simply popping Fostex drivers into existing boxes, then noodling with box calculators to see what was happening. I think it's critical to get those first few prototypes out of the way -- it's basically a process of elimination to end up with something you want to live with.

Hi rjbond3rd,

If I may take the liberty to rephrase or paraphrase or otherwise mangle your response in terms of the single driver magic, let's put you down for the eminent wisdom that once you build it you'll forever hence know it when you hear it - or don't hear it.

ie. Go for a quick experiential baseline and let that guide you.


-jerry

[GM]

Originally posted by Scottmoose

And so on. I'm not interested in following a particular philosophy -it's all tramlining. You go with the compromise that works best for you. Because everything is a compromise. Which suits you, only you know.

Yeah, this pretty much sums it up it since it depends on what the individual is expecting out of it. At the one extreme there's the 'I'll sacrifice whatever I have to keep it a single driver system' to folks like me that believes any serious HIFI/HT app other than possibly near-field (i.e. very small room, computer desk system, etc.) needs both LF and super HF augmentation to keep its various distortions vanishingly low in our acute hearing BW, preferably done actively multi-amped.

Once you move away from this you have to decide what trade-offs you're willing to accept (gain BW, dynamic headroom requirements, etc.) and this is so individual's hearing/room and location in-room/signal source dependent (not to mention the SO/WAF issue for some) that the number of different 'solutions' seems to approach infinity judging by all I've seen in ~12 yrs of browsing many of the various internet BBs/forums.

Bottom line, either build a well proven design that 'best' meets your needs overall or build/tweak till you find what works best for you overall in your app.

GM

[Jim Shearer]

The only thing I would add to Scott's comments is to emphasize: you have to get out and listen for yourself! How can you know what you want in a speaker if you have only heard a few examples down at the local big box store, where the environment prevents you from hearing them properly anyway?

A couple years back I wanted to get some new speakers, so I began to search the 'literature' (which these days is mostly the internet) and to seek out listening experiences by planning stops at hifi shops while traveling. I already knew pretty well what I wanted in terms of sound qualities, but I thought there might be new possibilities beyond what I knew from my searching back in the early '70s. I found speakers I liked, but didn't fit my listening environment, like Magnapans. I found speakers I liked but couldn't afford, like Martin Logans (need way pricey amps to drive them properly too.) Just as I was about to buy some Totems that were almost within affordability, our house needed a new roof. It was then I caught wind of speaker building and single FR drivers. If you know the sound you want, and you read lots of reviews (taking all of it w/ a grain of salt,) then you can get a clue as to what you might want to build. Then it's time to jump in & do it! I've only built two pair of speakers so far, but I'm lovin' what I hear, and having fun making them. I was warned in advance that speaker building is addictive, but I don't care. By the time I spend as much money building speakers as I would have buying that one pair of Totems, I'll have over populated our house and our relatives with great sounding speakers--and have had years of fun building them. And all that fun is priceless!

Cheers, Jim

PS: And thanks to Scott and all the others who make this possible by sharing their knowledge!