[Duke]

Have you ever wondered why someone doesn't make a speaker with a particular combination of characteristics?

Suppose you could bend the ear of a speaker designer - what would you tell him the audio world (or at least your corner of it) stands in need of? 

Greater tube-friendliness?  Deeper bass in a smaller package?  More bang-for-the-buck?  More artistic styling?  Different sonic emphasis?  What isn't being done that you think ought to be?

I don't know where this thread will go, but maybe it will be a useful dialogue between designers and enthusiasts.  And since it's on an open forum, this won't be my own secret market research - anybody can read or participate, and potentially benefit from the discussion.

If we end up with a fairly well-defined concept that I think I can build, and if there's interest, I'll at least take it to the prototype stage and discuss it with ya'll as I go along, getting your input.

So... tell me whatcha want!

Duke

[AdamM]

Grand idea for a thread topic

What do you guys think of this?

The challenge: High end sound, extreme minimalism.   No cables, no boxes, no entertainment units or shelving. Nothing but two beautiful speakers.   Two towers, two clean wires out the back you plug in the wall.  That's it

Built into each speaker would be a squeezebox, the amps, etc.  The squeezebox display would be tastefully integrated into the front of each speaker so you could see what's playing.  Absolute minimalism, deadly clean. Zero clutter.

They'd sell.  I know Bang & Olufsen get close to this idea, but they don't really nail it.

To us, hifi rigs are beautiful, but to many, it's an ugly room of cables and boxes and it looks dreadful.   Two towers, two wires, amazing sound.  Design and architectural magazines would be all over them.

/A

[lonewolfny42]

Hello Duke....

Good idea for a thread...

Having heard a few speakers, I'm listening first for a solid foundation...bass wise.
If the sound is thin...then it doesn't appeal to me....guess my personal taste.
Thats not to mean "bloated bass"....solid bass...clear.

Also....a higher-efficiency is better....more amps to choose from when looking for power.

And....sound stage....wide/open sounding....not a closed in sound.

Those are a few things that I would enjoy....

                                          Chris

[Duke]

Hi AdamM,

Thanks for the vote of encouragement.

Great concept!  You're thinking ahead of the rest of the industry. 

In addition to the AC power cords, wouldn't we need an umbilical connecting one speaker to the other?  Otherwise, assuming the program material is being played in the right speaker, how does the left channel signal get to the left speaker?  Or, am I missing something?

Unfortunately for me, what you describe is beyond my technical ability - but it's probably the wave of the future.  Geeze - I hope Boze doesn't read this thread before some serious audio company does!

Duke

[Duke]

Hello LoneWolf,

Again, thanks for the thumbs-up.

"Having heard a few speakers..."   No kidding??

Seriously, thanks for your input on getting the foundation right.  Yup, there are a lot of speakers out there that have really good "icing" but the "cake" isn't right. 

If you get a chance to stop by my room at RMAF (room 1100), I might have something new that does a pretty good job in the "openness" department as well.  I haven't gone public with it 'cause it's not finished yet, but the workshop prototype was promising.

Duke

[AdamM]

wouldn't we need an umbilical connecting one speaker to the other?

While a little 'wasteful' - you could use two squeezeboxes and just employ the one output for each side.  An unused channel on each one, sure, but now there's zero wires between them.

I'm not certain you can even use two squeezeboxes simultaneously like that...  but i'm sure it's figurable outable

Oh i hope Bose doesn't do it first

[lonewolfny42]

"Having heard a few speakers..."   No kidding??

I thought you'd like that.... 

See you in room 1100 Duke.....

[Audiovista]

Very timely post Duke....as far as I'm concerned 

I was just thinking about the speakers that would use a wide range driver (Fostex...) to cover the 100-5,000Hz range, no crossover, than woofer for below 100Hz (just an inductor in the crossover) and supertweeter for above 5 or maybe 7 or 8kHz (with only a capacitor in series). The frequencies are pretty arbitrary but a good designer can easily determine exact numbers. Maybe there is a speaker like that, I'm just not aware.

My guess is that below 100Hz and above 5kHz phase shift may not matter that much and the Fostex (or others) are covering the range where the ear is most sensitive. Also "beaming" could be avoided by having supertweeter.

Would that make sense? 

Boris

[IronLion]

I'd like to see more products that incorporate battery power into their design.  I am a huge fan of Vinnie's products and the batteries have a large part to do with that, it is very nice to not worry about AC issues or power cords and it just seems to be a simpler and cheaper way to power a system.  Obviously there are power limits when using batteries, but with sensitive speakers which I use this isn't an issue.   

[TONEPUB]

Grand idea for a thread topic

What do you guys think of this?

The challenge: High end sound, extreme minimalism.   No cables, no boxes, no entertainment units or shelving. Nothing but two beautiful speakers.   Two towers, two clean wires out the back you plug in the wall.  That's it

Built into each speaker would be a squeezebox, the amps, etc.  The squeezebox display would be tastefully integrated into the front of each speaker so you could see what's playing.  Absolute minimalism, deadly clean. Zero clutter.

They'd sell.  I know Bang & Olufsen get close to this idea, but they don't really nail it.

To us, hifi rigs are beautiful, but to many, it's an ugly room of cables and boxes and it looks dreadful.   Two towers, two wires, amazing sound.  Design and architectural magazines would be all over them.

/A

Im going to get pretty close to that in my living room with a Meridian 808 and a pair of their 7200 active speakers.
Not much clutter at all and great sound!

No one will ever put a squeezebox inside speakers, because when one thing goes you will be without the whole system, but its a great thought!

[Scott F.]

On the speaker side, I'm with Lonewolf, slightly higher sensitivity, minimalist design.

Like Chris I've heard lots of speakers. Many that claim to be tube friendly really aren't. Sure they have a Zobel in it to show a flatter impedance to the tube amp but every Zobel I've heard sucks the life right out of the sound.

If I had a research budget and loads of time to experiment I would construct a speaker like this;

First and foremost, use a 1st order XO. A simple cap and coil, no more, no less (unless you want to do the Zu and Infinity trick letting the woofer run wide open then cap a tweeter into the -6db point). If the designer does a good job of picking a driver that rolls off evenly and doesn't exhibit nasties at cone breakup on the upper frequency extremes, there is no reason you can't use a simple 1st order XO on the woofer (assuming it sounds good above 2.5k or so). The tweeter is less of a concern. Just push the XO frequency up a bit to handle the -6db slope and you'll have a decently flat XO point. Next, I'd position the drivers or construct the cabinet so that you have a minimal issue with baffle step compensation. Again, taking a notch filter out of the signal chain will keep from sucking up precious tube (and SS) power.

Sensitivity isn't crucial but I think its important. Something around 92 would be a good baseline for starters. You could always go with an MTM or an MMT design to increase the output assuming the tweeter is up to it (lobing issues aside). Reason I say this is that the majority of tube amps out there are 20+ watts. With 92+db and assuming you have decent output iron on the amp, you will drive them to very comfortable listening levels in a moderately sized room.

When it comes to cabinet design, I've recently listened to some very good sealed cabinet designs. They go deep enough that many people wouldn't require a sub. The plus side of this issue is that it should help in reducing the impedance peaks and phasing issues in a ported cabinet. As part of the overall design, the speaker needs to maintain less than (about) a 50ohm impedance peak. This will present a much easier load for the tube amp thus making it completely unnecessary to install the life sucking Zobel. The sealed cabinet isn't absolutely necessary, if you can extend the bass an octave or two without causing too many negative issues with the tube amp, all is well. A transmission line is an option too.

Think absolutely old school here. Designs and manufacturers like Dynaco, Advent, KLH and others didn't over design their speakers. They used common sense to produce speakers that worked well with tube amps. Sure, some of them used 2nd order XO's which aren't horrible but it does add a tremendous expense to the speaker (if you use quality parts) plus it does suck just a bit more life out of your speaker (more parts=less life). Granted, the speakers and passives of the day didn't sound all that terrific but any amp of the day would drive them without a problem.

Even though speaker technology has advanced, not many 'designers' have figured out all they have to do is look to the past to come up with a good sounding speaker. They all want to come up with some new fangled approach to crossover design that they can tout as 'inventive' or 'novel' and use as ad copy to sell their product. I know, I know, I just made a wide sweeping statement that doesn't hold true in every instance.

The KISS principal is all you need to succeed, honest. It will take work. Nowadays, it seems that speaker designers and manufacturers are far less concerned about a speakers interaction with a tube amp because they know if they put enough bandaids in the filter circuit, they can get it to measure flat.

Oh, when you test your tube friendly speaker designs, don't use some monster 150wpc tube amp. Try a simple push pull EL84 design with reasonable output iron and very little NFB. If it works with this amp, it will work with nearly anything.






....sorry for the (sort of) mini-rant against conventional speaker designers. sure, if you are using solid state, you have no issues because it can handle the extra load seen by the speaker but so few actually design speakers specifically for tube amps. if they really understood the interactions, there would be a wider selection of truly tube friendly transducers out there.....but then again, I just ranted some more........sorry 


..just my $.02 from a grumpy minimalist 

[hmen]

I'd like a line array that doesn't need a sub.

[WEEZ]

Somewhat along the lines of Scott's post....

1) smooth impedence; ( 8 ohm min.)...low reactance
2) acoustic suspension design
3) no larger than 1 cu. ft
4) can actually be used with a grill cloth attached

(We probably don't see many acoustic suspension speakers anymore because most 'off-the-shelf drivers' have the wrong T&S 'specs' to be used that way; and because people have become accustomed to the sound of a reflex loaded speaker.)

Easier said than done, right?

WEEZ

[Kevin Haskins]

Somewhat along the lines of Scott's post....

1) smooth impedence; ( 8 ohm min.)...low reactance
2) acoustic suspension design
3) no larger than 1 cu. ft
4) can actually be used with a grill cloth attached

(We probably don't see many acoustic suspension speakers anymore because most 'off-the-shelf drivers' have the wrong T&S 'specs' to be used that way; and because people have become accustomed to the sound of a reflex loaded speaker.)

Easier said than done, right?

WEEZ

Yea... a true 92db/1W/1M type of loudspeaker in a sealed box design of that size would get you to about 180Hz f3.      Those laws of physics are a real bitch. 

[WEEZ]

Except, Kevin, I don't care about 92db sensitivity...I was carefull not to mention that

WEEZ

[Kevin Haskins]

I'm just being PIA.     If you don't care about how sensitive it is you can pick an F3 & box size and back calculate the driver parameters needed.    You also have to consider if your going to use some sort of baffle step compensation which eats another 3-4db of output below the baffle step.    Other than that the T/S parameters are very accurate for low frequency output of a sealed box system.   

[Duke]

Wow, what a great collection of replies!  Thank you all so much!  This may take me a while (have lots to do today), but I want to respond to each of you.

First, to Boris/Audiovista:

I think your idea is great!  Using a "fullrange" driver but providing subwoofer and supertweter is a very appealing concept.  Actually, my first commercial loudspeaker was exactly that, and while it was hardly a screaming success in the marketplace I may well revisit the concept some day.

My first commercial speaker used two 8" Fostex drivers in a sealed bipole configuration (much better power handling than using one in dipole), along with a built-in powered woofer section to handle the bass below 140 Hz or so.  The high frequencies actually held up pretty well on-axis, so I added a rear-firing supertweeter to augment the high frequency balance in the reverberant field.  A front-firing supertweeter that kicked in a little north of 10kHz was an option.

The Fostex driver had a peak around 6 kHz, and I used a notch filter to smooth it out.  Notch filters are controversial, but I think I've found a way to keep them from sucking the life out of the sound.  One of the three components is especially critical when it comes to sound quality. 

Because I was "cheating" by using a powered woofer section and a bunch of rear-firing drivers, I called my speaker the "Cheetah".   Here's a link to a little write-up:

http://www.sonicflare.com/archives/vtv-expo-audiokinesis.php

And, a comment from someone who heard 'em (near the middle of this post):

http://www.audioasylum.com/audio/general/messages/410442.html

Okay, that was the good news.  Now here is the bad news about the format:

If you crank the volume level up and/or hit the speaker with complex orchestral or choral passages, the midrange clarity and articulation isn't very good.  Possible reasons for this are small linear x-max on the Fostex driver (1.5 mm, and I think that's one-way); dynamic flux modulation in the motor; intermodulation distortion of the higher frequencies; and diffraction or break-up associated with the wizzer cone. 

So I had a speaker that sounded great at low volume levels, great with most music at medium volume levels, and pretty much sucked at high volume levels.  I tried raising the crossover point to make life easier on the Fostex drivers, but that didn't make much difference.  Finally the woofer I was using was discontinued, calling for a major redesign.  The result was a speaker that was bigger and more expensive than the origial, but was outclassed in dynamic capability by most of its competition.   

Now all of that being said, I may revisit the concept in a simpler, less expensive package if I can figure out a way around the problem of congestion in the midrange as the music becomes demanding.  I suspect that flux modulation is the main culprit, as I've heard very similar coloration with another woofer, and the coloration disappeared when the motor was changed to a version with a Farady ring.  Unfortunately I don't know of any low-priced fullrange drivers with low-flux-modulation motors, and fullrange is the applicaion in which flux modulation is most likely to be audible.

I still have a pair of the revised version, which uses a single 12" sealed-box woofer, in case you'd like to try 'em out.  If you might, shoot me an e-mail or message.

Thanks for your suggestion, and let me know if you have any questions or follow-up ideas.

Duke

[Duke]

Hi IronLion,

I take it you're referring to an active speaker that runs off of a rechargeable battery?  Hmmm.... if you had let's say two sets of quick-charge lithim batteries, I can see how that could work - assuming one set could charge up quicker than you could run the other set down.

This is beyond the scope of what I do, but I think it could be done by a company with sufficient resources.

Thanks for your suggestion!

Duke

[Duke]

Hello Jeff/Tonepub,

Thanks for your input!  Yeah I shoulda thought of Meridian - and hopefully if AdamM's ultraroomfriendly format goes into production it'll be Meridian and not Boze that does it. 

It has been a long, long time since I really sat down and listened to a Meridian system.  They made one of the best little speakers of its era - the active M2, from the early 80's.  Boy those little suckers could punch and image.

Hey I have always enjoyed your stops by my room at audio shows - great to see how well your magazine is doing! 

Best wishes,

Duke

[TONEPUB]

Hey there Duke:

Good to see you out here, it's a nice group!

I won't be at RMAF this year, due to some family issues, but definitely
at CES...

How is your speaker coming along....