I believe my HT speakers retain most of the positive attributes of a singe FR driver, while using 9 drivers. First of all, each one is the same model of one of the widest bandwidth, longest excursion ~3" FR drivers in existence, and modified to extend approximately a third of an octave lower than stock (based on Fs). As a result, there is no significant discrepancy between any of the drivers regarding their acoustical signatures or dispersions.
Secondly, they are arranged as a single vertical array per speaker with the drivers symmetrically frequency shaped.
Thirdly, baffle step correction is achieved with first order LP filtering of the outer six drivers (3 upper and 3 lower only), so that the 3 center drivers are running without any frequency shaping at all up to ~5khz. Finally, essentially flat response out to 20khz is achieved by boosting the center driver only while rolling off the 2 surrounding it with a single component. This is probably one of the least sonically intrusive ways that passive components can be used to shape speaker system response. Another result of this means of flattening the overall response (when considering the 5 1/2" diameter circular cross section of the enclosure) is that both good vertical and excellent horizontal dispersion are achieved without any sudden discrepancies within the passband. Also, the phasiness of a conventional array becomes a non-issue with this stepped and symmetrical frequency shaping approach.
Of course, this is not intended to be an ultimate quality reference system - just one that will in a HT system sound as little like a 'speaker' as possible and have excellent naturalness, neutrality, articulateness, bandwidth (when Audyssey MultEQ is activated, the effective bandwidth is from below 30hz to ~20khz), and that can handle the dynamics and detail of high resolution audio at realistic levels.
When I first played the Master and Commander Blu-Ray using the DTS Lossless soundtrack, the sonic experience greatly contributed to me becoming disoriented to the extent that I had trouble remembering what year it was, etc. for some minutes after one battle scene. When I played Secretariat, some of the hoofbeat sounds in conjunction with shots of churning horseflesh during the racing scenes actually caused me to cringe involuntarily. When I played Top Gun, some of the afterburner LF sounds made me want to break out the marshmallows (ok, I made that last one up).
Anyway, for HT at least, these speakers (along with the Onkyo HT receiver I'm using), really seem to fill the bill for producing involving Surround Sound, to the extent that I am seriously doubting whether subwoofers are really that necessary. And I believe that designing them to retain the majority of the sonic advantages of single FR driver systems with minimal component frequency shaping while adding considerably to their overall dynamics, flatness and frequency range significantly contributes to this.
Secondly, they are arranged as a single vertical array per speaker with the drivers symmetrically frequency shaped.
Thirdly, baffle step correction is achieved with first order LP filtering of the outer six drivers (3 upper and 3 lower only), so that the 3 center drivers are running without any frequency shaping at all up to ~5khz. Finally, essentially flat response out to 20khz is achieved by boosting the center driver only while rolling off the 2 surrounding it with a single component. This is probably one of the least sonically intrusive ways that passive components can be used to shape speaker system response. Another result of this means of flattening the overall response (when considering the 5 1/2" diameter circular cross section of the enclosure) is that both good vertical and excellent horizontal dispersion are achieved without any sudden discrepancies within the passband. Also, the phasiness of a conventional array becomes a non-issue with this stepped and symmetrical frequency shaping approach.
Of course, this is not intended to be an ultimate quality reference system - just one that will in a HT system sound as little like a 'speaker' as possible and have excellent naturalness, neutrality, articulateness, bandwidth (when Audyssey MultEQ is activated, the effective bandwidth is from below 30hz to ~20khz), and that can handle the dynamics and detail of high resolution audio at realistic levels.
When I first played the Master and Commander Blu-Ray using the DTS Lossless soundtrack, the sonic experience greatly contributed to me becoming disoriented to the extent that I had trouble remembering what year it was, etc. for some minutes after one battle scene. When I played Secretariat, some of the hoofbeat sounds in conjunction with shots of churning horseflesh during the racing scenes actually caused me to cringe involuntarily. When I played Top Gun, some of the afterburner LF sounds made me want to break out the marshmallows (ok, I made that last one up).
Anyway, for HT at least, these speakers (along with the Onkyo HT receiver I'm using), really seem to fill the bill for producing involving Surround Sound, to the extent that I am seriously doubting whether subwoofers are really that necessary. And I believe that designing them to retain the majority of the sonic advantages of single FR driver systems with minimal component frequency shaping while adding considerably to their overall dynamics, flatness and frequency range significantly contributes to this.
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To come back to the original question: a whole lot. It might even require a modification of physics as we know it (1). Plus improvements in way the brain processes sound (2).
Ad (1): beaming. Plus a lot of mechanical issues.
Ad (2): the brain is only capable of distinguishing phase differences between the two ears, but fails completely in distinguishing phase shift with frequency if it is congruent.
In other words, we would have to be able to make a completely rigid disk that doesn't beam in order to get the speaker part right. And, unless we improve the brain, even 48 dB steep filters at 2 Khz with a 360 degree phase shift cannot be distinguised from what is the purist's quest. So why not use them darned filters, if this makes other things better?
Ad (1): beaming. Plus a lot of mechanical issues.
Ad (2): the brain is only capable of distinguishing phase differences between the two ears, but fails completely in distinguishing phase shift with frequency if it is congruent.
In other words, we would have to be able to make a completely rigid disk that doesn't beam in order to get the speaker part right. And, unless we improve the brain, even 48 dB steep filters at 2 Khz with a 360 degree phase shift cannot be distinguised from what is the purist's quest. So why not use them darned filters, if this makes other things better?
... needs to be done for a typical cone & dome 2-way to measure up to the coherance of a good full-range. The big problem is a dome that will go low enuff that the XO is where it is least obnoxious (ie <400 Hz). You have to remember, crossovers are evil.
Ha, ha, ha...
dave
I don't think so. The attack and decay are only part of the story. During the sustain (or at least what passes for sustain with a plucked/struck string), the harmonic series will be different. Take for instance a violin which has a very complete harmonic series, a clarinet which has only odd harmonics and a French horn which has predominantly the fourth harmonic. You do not need the attach and decay to tell these instruments apart.
Bob
I was going to get a FR for my metal constructed garage but went with 6 foot tall line arrays to fight the beer can sound. Hundreds of everything later (waiting for more parts) ... I want a FR system for my computer.
The MA CHP-70 looks about right and maybe a transmission line (?) might keep me from turning on the subwoofer. Since the speakers are a meter away, not much need for a powerful amplifier so the USB Topping T-Amp should do well. I'm rather edgy about FRs so dipping my toe in the pool of one speaker and two wires makes me curious. Like the MA stuff since Planet 10 gives them the thumbs up (why Enable junk drivers?) The frequency response charts look good as the "shout" of FRs tends to annoy me.
Maybe high grade computer speakers can push the smaller FRs into the limelight? Have some Tang Band 3" FRs with the phase plug in wood boxes and they sound shockingly good (for what they are) Rumor has it that Aurasound will bring out new 3 and 4 inch drivers pretty soon so these are exciting times.
Near field monitors seem to be a good match for smaller FRs from what I understand. Sitting on axis should solve the treble roll off issues so is it a good "first FR" or am I way off-base here? 😕
The MA CHP-70 looks about right and maybe a transmission line (?) might keep me from turning on the subwoofer. Since the speakers are a meter away, not much need for a powerful amplifier so the USB Topping T-Amp should do well. I'm rather edgy about FRs so dipping my toe in the pool of one speaker and two wires makes me curious. Like the MA stuff since Planet 10 gives them the thumbs up (why Enable junk drivers?) The frequency response charts look good as the "shout" of FRs tends to annoy me.
Maybe high grade computer speakers can push the smaller FRs into the limelight? Have some Tang Band 3" FRs with the phase plug in wood boxes and they sound shockingly good (for what they are) Rumor has it that Aurasound will bring out new 3 and 4 inch drivers pretty soon so these are exciting times.
Near field monitors seem to be a good match for smaller FRs from what I understand. Sitting on axis should solve the treble roll off issues so is it a good "first FR" or am I way off-base here? 😕
But you would need frequencies other than the fundamental. Harmonics are also what makes instruments sound different from each other, but as full range drivers show, they don't need to be in perfect proportion to each other (non flat fr response).
IMO it is the attack and decay that our brain relies on most to distinguish what's real and what's real and what's reproduced. All of this together makes the timbre, but again I believe a coherence in time is what makes our brain tick. Once it's not coherent in time, no matter how flat the response is, our brain immediately knows it's not real.
IMO it is the attack and decay that our brain relies on most to distinguish what's real and what's real and what's reproduced. All of this together makes the timbre, but again I believe a coherence in time is what makes our brain tick. Once it's not coherent in time, no matter how flat the response is, our brain immediately knows it's not real.
Hi RJ,
You are skating on thin ice!
My nick is Vacuphile only because of my twisted sense of humour; it is a statement against the concept of 'horror vacui'. But it does not at all imply that I favour vacuum tube amplifiers for other than decorative pusposes.
On a more serious note: the way a loudspeaker performs is highly dependant on the interaction with the amplifier that preceeds it. Tube amps, with their high output impedances, therefore are not at all optimal (unless they are used with a speaker that specifically takes this into account).
Another speaker/amplifier interface problem occurs with ss and tube amps alike, and is caused by the crossover. This in my mind might explain why so many still appreciate FR, in spite of their measurable shortcomings. A crossover effectively isolates the speaker from the amplifier, diminishing the dampening factor, etc. Because V and I run out of phase, the amplifier has to be able to sink currents that are out of sync with voltage. So, I suspect that the more coherent sound many hear in FR speakers has to do with this; the speakers behind a X-over are to loosely coupled with an amplifier stage that gets confused by a complex load.
Therefore, my present design philosophy for speakers is based on active (analog) filtering with dedicated amplification for each driver. SS, more specifically, class D.
Please eat your hat, or rather, build a 2 way based on this principle 🙂
Hi Dave,
see my previous post in answer to RJbond. Crossovers are evil, I agree. That is, when placed between amplifier and drivers. But the principle of crossing over so that two drivers can each do what they do best makes good engineering sense. By actively crossing over you can have the best of both worlds; coherence because the drivers are tightly controlled by the amps, and relatively flat requence response with a benign of axis behaviour.
regards,
Vacuphile
Hi vacuphile,
Aha! So your philosophy might be paraphrased as "less is more." Then I think you are a perfect candidate for a system with very few parts 🙂
In all seriousness, I am building strictly two-ways now, but the crossover is mechanical in nature, made of wood, specifically, a horn-like device. Some pros, some cons, same as everything. Wouldn't you agree there are multiple valid approaches?
Aha! So your philosophy might be paraphrased as "less is more." Then I think you are a perfect candidate for a system with very few parts 🙂
In all seriousness, I am building strictly two-ways now, but the crossover is mechanical in nature, made of wood, specifically, a horn-like device. Some pros, some cons, same as everything. Wouldn't you agree there are multiple valid approaches?
Interesting,
Is there a 4" full range out there that can do 7 octaves without rising response (shout) and will go down to 70 or 60 Hz with authority? Just want something to do 60 Hz to 9 KHz with active subwoofers and active super tweeters to cover the frequencies that the brain does not concentrate on. T-Amps, active XO and small 4" wide bands would make a nice personal "computer" audio system for near field enjoyment.
I keep reading how your brain adjusts to the problems with FRs. I don't think my brain will adjust well since my home theater is used often, the car stereo runs and I have a line array under construction in the garage. Sure, if I had one dedicated room to listen to full ranges and had a basic car audio system, I can understand the adjustment. Since I will use 4 specific sound systems daily, I don't understand how my mind can "forget" beaming highs and and lack of below 80 Hz very well.
My family would beat my butt if I kept the HT and car audio systems shut off for a few months while my ears are in full range training.
😉
Is there a 4" full range out there that can do 7 octaves without rising response (shout) and will go down to 70 or 60 Hz with authority? Just want something to do 60 Hz to 9 KHz with active subwoofers and active super tweeters to cover the frequencies that the brain does not concentrate on. T-Amps, active XO and small 4" wide bands would make a nice personal "computer" audio system for near field enjoyment.
I keep reading how your brain adjusts to the problems with FRs. I don't think my brain will adjust well since my home theater is used often, the car stereo runs and I have a line array under construction in the garage. Sure, if I had one dedicated room to listen to full ranges and had a basic car audio system, I can understand the adjustment. Since I will use 4 specific sound systems daily, I don't understand how my mind can "forget" beaming highs and and lack of below 80 Hz very well.
My family would beat my butt if I kept the HT and car audio systems shut off for a few months while my ears are in full range training.
😉
Hi RJ,
Absolutely, if the same can be achieved with less, that's more.
I do agree that there are multiple valid approaches. As a matter of fact, I believe there is an infinite number of equivalent alternative solutions for pretty much any problem. It just might take some more work discovering stuff to get there.
Active XOs have the potential to be less evil, but still need to have C-C distances of drivers <1/4 wavelength.
And they need to be phase/time coherent.
dave
Shout is different from rising response. Not all fullrangers have rising response. But for the ones which do, the rising response is designed right in, whereas shout is an unfortunate defect (which can be cured in a number of ways and is sometimes worth the effort).
Rising response is basically due to the strong magnet, which damps the low frequencies. A strong motor is a positive thing in some situations. If you have one of those drivers, you just design a horn for it. The horn lifts up the bass and flattens out the lower part of the response.
If the overall response is still not flat due to baffle step, then you address that in any of several ways (e.g., make the baffle wider, add a second .5 driver, add a circuit, redesign the horn to be a better match, etc.)
Getting to 60Hz is easy. It's harder to get to 40hz and sometimes that's just too far for a given driver. Some 4" can play with surprising authority at 60Hz and even 40Hz but will never match a 15" woofer for bump. So you combine them.
As far as the brain goes, I think the brain is also forgiving of multi-ways. That's why many people end up with two systems. I don't think there's much of a period of "ear training" -- you just listen to all your old music and hear it differently. Some will be better, and some worse (unlistenable even).
Rising response is basically due to the strong magnet, which damps the low frequencies. A strong motor is a positive thing in some situations. If you have one of those drivers, you just design a horn for it. The horn lifts up the bass and flattens out the lower part of the response.
If the overall response is still not flat due to baffle step, then you address that in any of several ways (e.g., make the baffle wider, add a second .5 driver, add a circuit, redesign the horn to be a better match, etc.)
Getting to 60Hz is easy. It's harder to get to 40hz and sometimes that's just too far for a given driver. Some 4" can play with surprising authority at 60Hz and even 40Hz but will never match a 15" woofer for bump. So you combine them.
As far as the brain goes, I think the brain is also forgiving of multi-ways. That's why many people end up with two systems. I don't think there's much of a period of "ear training" -- you just listen to all your old music and hear it differently. Some will be better, and some worse (unlistenable even).
My 1st major listening session with Alpair 7 was enlightening .. 4 hrs glued to the couch with iTunes on random, i found myself listening to, and appreciating, stuff i'd normally skip over.
dave
Hi Dave - could you remind us exactly what enclosure the Alpair 7s were in - size and dimensions? This is without subwoofer, right?
The Alpair 7 is a real contender it seems, hot on the heels of the Alpair 10 revision. Am I picking up a preference for the 7?
Andy
The Alpair 7 is a real contender it seems, hot on the heels of the Alpair 10 revision. Am I picking up a preference for the 7?
Andy
This session would have been with stock Alpair7 in the prototype dMar-Ken7 no woofers. Even better now, slightly tweaked bos, treated drivers. Yes i prefer 7 to 10, which i prefer to 12. But all are very good, and very much of a family. My value of a really solid and deep 3D soundstage, and maximum midrange finese makes the A7eN the winner, if you value ultimate dynamic peaks (as opposed to DDR) and more bass weight then the A12eN moves ahead. A10 is in the middle.
I figure A7 plus helper woofers will give the best of both ends of the spectrum.
dave
As a newbie to FR, similar feeling for me with my first FR system. Started to pick out stuff that I never noticed before; acoustic and jazzy tracks had a whole new meaning for me. I think my listening style and in some cases taste have changed over the last 3 months. Appreciation for musicality and sound stage have increased, hankering after power and SPL has been reduced. A training of the brain for me perhaps....
-Zia
p.s. Dave, now I really want Alp 7 too....
I have this sneaking suspicion that dave is going to get some money from me for those Enabled drivers eventually. 😱
I noted the Mark Audio drivers have a rising response on the bass side for baffle step and the right BLH design should do the trick. My shout paranoia should be tamed with the Enable trick? I want to use active filters for adjustment ability and I can always turn them off to run purist full range. Besides, I think a BLH design with an Enabled full range just looks great.
Thanks guys, after I finish the line arrays in the metal garage (acoustical hell) build the tapped horn to go with it--I should have read all the info I need to start making sawdust. The desk top system becomes critical when water starts to freeze. 😎
I noted the Mark Audio drivers have a rising response on the bass side for baffle step and the right BLH design should do the trick. My shout paranoia should be tamed with the Enable trick? I want to use active filters for adjustment ability and I can always turn them off to run purist full range. Besides, I think a BLH design with an Enabled full range just looks great.
Thanks guys, after I finish the line arrays in the metal garage (acoustical hell) build the tapped horn to go with it--I should have read all the info I need to start making sawdust. The desk top system becomes critical when water starts to freeze. 😎
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