bass reflex vs, acoustic suspension and japanese speakers

[veganaudio]

Hello Sound fans:

I have this memory of my youth (the 80's)of this small acoustic suspension speakers that had the most tight bass response ever....they were japanese -Technics SB-F2 (2 way)- placed on this small tripods.

Maybe the hard wood floor had a lot to do too with it and not too many furniture in that room, it was perfect.....ahhh what a memories.....


Later in the 90's my roommate had this old tower Technics (4 way), bass reflex this time, that sounded awesome with his old silver Kenwood Amplifier and Onkyo CD changer.

Are japanese speakers very good or they just fit my ears?


Any one with comments about this two types of speakers (Bass Reflex vs. Acoustic suspension) and japanese speakers???


Thank You

[RGA]

Japanese speakers from the likes of Sony Pioneer were atrocious - mostly still are.

Though There are some good Japanese speakers no doubt I can't think of one off hand other than Kondo - but I doubt any of us could afford them.

As for Acoustic Suspension - My AN K is one of the few if only Acoustic Suspension standmount speakers still being made - and I agree with you on the bass. The other advantage of the K is that not only is it tight it is also deeper than what I heard out of the competition - and amazingly easier to driver and more sensitive(something not usually associated with Acoustic Suspension speakers.

Though Acoustic Research made plenty of Acoustic Suspension speakers which had good sensitivity ratings - and even looked almost identical to my K. SO check out the used shops and see what turns up. Audio Note basically bought out a lot of defunct companies or models and used the original designs - tweaked them up and used far better parts. The AN K is based of the original Snell Type K form the 70s and Audio Note turntables are re-invisioned Systemdek II or Voyd tables. It wasn't broke so don't fix it. ---just a bit of tweaking.

[Woochifer]

The thing about ported bass reflex speakers is that they are more difficult to design correctly, which is why acoustic suspension speakers were the norm for a long time. The advantage of ported speakers is that they are more efficient and will have more even tonal response down to the tuned port frequency. Once you go below the tuned frequency, then the drop off is very steep. With an acoustic suspension design, you need a more powerful amp and the low end will taper off much sooner than with a comparable ported design, however this tapering off will occur much more gradually than with the ported speaker. This means that you'll have deeper bass extension, but lowered output higher in the bass range. Subjectively, some listeners feel that this more gradual tapering off in the bass response sounds more natural, which is why a lot of high end subwoofers still use the acoustic suspension design. So, both approaches have their tradeoffs.

More and more speaker makers have gone to the ported design simply because they've figured out how to make them better than before. Computer models allow for speaker designers to test a much wider range of parameters without having to actually build and test hundreds of different cabinet and port configurations. Acoustic suspension speakers in general are more consistent in how their bass sounds, and the absence of a port means that they are easier to place. However, ported speakers have the advantage of a more linear bass response and higher efficiency. The key to decent sound is getting the match between desired distortion levels, the cabinet volume, and the port opening done correctly. With a ported speaker, more variables need to be accounted for and speaker designers have gone to the design more as they've learned how to balance these variables to achieve a desired type of sound.

I don't think you can generalize about how a speaker will sound based on its design, since I've heard good and bad examples of both types of designs. But, I will say that while Japanese companies are very capable of building high value audio components, they've never been able to consistently produce decent speakers that compete with what U.S., Canadian, and British companies put out. Most of the speakers that Japanese companies make get mixed in with prepackaged audio systems. You don't frequently see them sold on their own.

[RGA]

Woochifer

It is interesting you note this defficiency in sensitivity but of course perhaps companies left using computer models to improve Acoustic Suspension designs because the AN K is standing proof that you can get highish efficiency - higher than most comparably sized port designs(and bigger) - with a far easier impedence load while maintaining all the other properties associated to Acoustic Suspension - I agree with the "type" of bass is different.

Basically what I am saying is that many never bothered to make Acoustic suspension better but they used computers to improve the ports - why not use computers like Audio Note to make acoustic suspension better? If they're easier to place and have a smoother roll-off and I can attest they are very room friendly - a pain to set-up correctly but even not set-up right they still offer a pleasing result then It's odd. I looked on a site about Acoustic Suspension standmounts from AR and they were all 87db up to 90db. You can buy a lot of ported standmounts today which are also no better than that range and have some ugly min impedence numbers. Good and bad of both I suppose is correct - I usually pay no attention to the design but to the sound - and then after I try and figure out what it was I liked or disliked.

[Woochifer]

Woochifer

It is interesting you note this defficiency in sensitivity but of course perhaps companies left using computer models to improve Acoustic Suspension designs because the AN K is standing proof that you can get highish efficiency - higher than most comparably sized port designs(and bigger) - with a far easier impedence load while maintaining all the other properties associated to Acoustic Suspension - I agree with the "type" of bass is different.

Basically what I am saying is that many never bothered to make Acoustic suspension better but they used computers to improve the ports - why not use computers like Audio Note to make acoustic suspension better? If they're easier to place and have a smoother roll-off and I can attest they are very room friendly - a pain to set-up correctly but even not set-up right they still offer a pleasing result then It's odd. I looked on a site about Acoustic Suspension standmounts from AR and they were all 87db up to 90db. You can buy a lot of ported standmounts today which are also no better than that range and have some ugly min impedence numbers. Good and bad of both I suppose is correct - I usually pay no attention to the design but to the sound - and then after I try and figure out what it was I liked or disliked.

Well, if I remember right, you noted that the AN was designed for corner placement. This basically means that they rely on that corner reinforcement to prop up the bass. With an acoustic suspension speaker, corner placement is easier because you don't have to worry about port noise. Obviously, if your room can't accommodate the speakers close to the corner, then it will sound a lot different in the more typical front wall placement.

Acoustic suspension speakers are simpler to design than ported speakers, because you don't have to design the speaker cabinet around a tuned frequency. You basically build a box, install the components, seal the driver enclosure, and you're in business. There are things to consider with the interior volume and the Q-alignment you want, but more often than not you won't wind up with something that just doesn't sound right. Basically, there's a lot more room for error, and that's why sealed boxes are usually what DIY hobbyists start with. With a ported speaker, you have to figure out what bass depth you want, and then find a precise match between the required interior volume and the size of the port opening. When done correctly, the ported speaker will have a more linear bass response down to the tuned frequency. If this is not done correctly, then you wind up with distortion.

Those AR speakers may have been efficient, but if you stuck those same drivers and crossover networks into a ported cabinet, then the sensitivity would still be higher.

[RGA]

Interestingly, I have pulled the speakers out from the corner and the sound is more open.

When I first auditioned the speaker though they were not in a corner but close to a wall. The rating frequency and sensitivity of the speaker is under a normal position. In a corner bass is rated to 36hz and the db rating should rise to 93db if that H/T calculator site is correct. It makes sense because in the corner the sound is louder at the same volume settiing - whether your preference for the sound in the corner is ideal is up to the individual.

The AN E is designed for a corner as well desopite being rear ported but Hi-fi choice mentions it measures confirms it best as free-standing - perhaps because the bass distortion is so low one can get away with them in a corner and not notice any irregularity that a graph produces - I have heard the E in both positions and there is a smidge less expressiveness in the vocals when in a corner but the bass is greatly enhanced.

The only issue I have with the K has been that with every alteration i make to position makes a very noticeable change to the sound I get. With my B&Ws and even my Wharfedales they were mostly the same or at least nothing to write home about. But if the K is too close to a wall it sounds thumpy to far away and thins out not toed in enough the soundstage is undefined - too far in and it something seems missing. Yet oddly once it's set you can sit anywhere across the front with a large seating position and the sound moves with you as you move like eyes on a painting so it doesn't sound "shifted."

Toe in seems to be important for side wall reflections but the manual states it will operate Parallel to the wall as well - which I have not tried - because I'm sick of pulling the stands out of the carpet - and it's bloody heavy. Then there is the tilting which is not stated but they probably assumed the buyer would buy the AN stands.

You know I think we should just buy a freakin system and be happy - They simply will sound different to different people in different rooms and set-ups anyway - and if there was one right answer there would be one speaker. There isn't so....

[gonefishin]

Woochifer

It is interesting you note this defficiency in sensitivity but of course perhaps companies left using computer models to improve Acoustic Suspension designs because the AN K is standing proof that you can get highish efficiency - higher than most comparably sized port designs(and bigger) - with a far easier impedence load while maintaining all the other properties associated to Acoustic Suspension - I agree with the "type" of bass is different.

RGA, where in the heck do you get your information? Of course you can still achieve high(ish) efficiency design with acoustic suspension designs...but that's dependant on the driver being used. Put it in a vented cabinet and the same driver would have an even higher overall efficiency.
The enclosure will eat up power just as a passive crossover will.


I suspect your constant ramblings and misinformation are driving a good number of people away from an otherwise nice sounding speaker (talking about AudioNote Speakers).

[skeptic]

While it is true that there are good and bad examples of both design principles, they are actually worlds apart. I discovered about 15 years ago that you could apply Newtons second law of motion to loudspeakers, especially woofer/enclosure designs and completely understand them at least mechanically. I thought I had seen something new and then started reading Sam's Audio Engineering Reference Handbook and saw that the people who were on the cutting edge of mathematical modeling of woofer design were way ahead of me. Still many designers use cookbook recipes and apply software blindly without knowing why they do what they do.

Basically, a loudspeaker is a resonant device meaning it wants to vibrate at some frequencies and not at others. What the speaker designer wants ideally is a device that doesn't appear to want to vibrate at any particular frequency or group of frequencies at all over a very wide range of 10 octaves, the range of human hearing. To do that, not only do they use multiple drivers, each optimized for a smaller range of frequencies but they have to "tune" each one in effect optimizing it within its range. Acoustic suspension drivers/enclosures and drivers intended for ported enclosures and their enclosures are tune according to entirely different methods.

Three factors interact to play the determining role of what the frequency response will be. First is the mass. How heavey is the cone and other moving elements. Second is the spring constant which restores the cone to its neutral position after the electromotive force of the opposing magnetic fields of the coil and field magnet are removed. Third is an aerodynamic drag factor which dampens the motion. This factor is related to the velocity of the moving cone. We normally associate it with viscosity but you can't change the viscosity of air.

The true acoustic suspension woofer has a very low inherent springiness. Its spring comes from the difference in the air pressure trapped inside a sealed box and the pressure outside of the box. The huge advantage of this is that the force is independent of frequency but only dependent on the air compression or rarifaction. The drag is controlled often by fiberglass batting inside the cabinet causing the cone to have to suck or squeeze air between the fibers in order to overcome the difference in pressure. This makes it relatively easy to tune an acoustic suspension speaker to have a very flat frequency response down to a very low frequency and to fall off relatively gradually below that frequency. This means that using electrical equalization either within the crossover or at the line level, the response can be further extended to some degree. The tradeoff is relatively low efficiency but with advances in making powerful magnets for speakers in the last couple of decades, efficiency has improved.

Ported designs use drivers with mechanically much tighter suspensions which are needed to restore them when the electrical signal applied to them is zero. The enclosures are designed to reverse the phase of the sound coming from the back of the cone so that it is in phase with the front wave when it emerges from the box. The enclosure also has a port or pipe inside which acts much the way the pipe in an organ or reed or wind instrument works. It has a column of air inside which is very easy to move at some frequencies and not at all easy to move at others. The frequencies of "resonance" depends on the length of the pipe. The resistance of air and hence the springiness of the resistance to the woofer's movement becomes a very strong function of frequency. The speaker is very efficient at the "tuned" resonant frequency and at multiples of that frequency but very difficult to move at frequencies in between. It is extremely difficult to overcome this phenomenon. Because the resistance to moving air changes so sharply when you move away from the tuned frequency, ported speakers are considered to only be useful down to that frequency and not below it. To get this frequency very low requires an enclosure with large dimensions and so ported speakers that are reasonably small generally don't have the ability to reproduce the lowest tones you can hear.

There is no reason Japanese manufacturers cannot make outstanding loudspeakers. In general though, they don't seem to have. A notable exception is Yamaha NS 1000 which has a cult following and is a collector's item. I am sure in the future, Japanese high end manufacturers will catch up and produce some of the top rated models.

[Pat D]

There is no reason Japanese manufacturers cannot make outstanding loudspeakers. In general though, they don't seem to have. A notable exception is Yamaha NS 1000 which has a cult following and is a collector's item. I am sure in the future, Japanese high end manufacturers will catch up and produce some of the top rated models.

Very interesting post, skeptic. As for Japanese speakers, there have been some good ones. I heard the Yamaha NS-1000 many years ago and thought it was a very fine speaker. I still have a review by Richard C. Heyser in Audio magazine somewhere. There have been other nice sounding Yamaha speakers, too, but I haven't preserved the model numbers, except perhaps NS-500 and NS-10 (a smallish speaker, I think).

I also heard quite a good Technics speaker many years ago, the model number SB-7000 sticks in my head, but may be wrong. Anyway, these were claimed to be phase coherent but did sound quite good, I thought.

So the Japanese are quite capable of making good speakers, though they often don't--but then the same is true for the Americans, British, and so on.

[Woochifer]

Very interesting post, skeptic. As for Japanese speakers, there have been some good ones. I heard the Yamaha NS-1000 many years ago and thought it was a very fine speaker. I still have a review by Richard C. Heyser in Audio magazine somewhere. There have been other nice sounding Yamaha speakers, too, but I haven't preserved the model numbers, except perhaps NS-500 and NS-10 (a smallish speaker, I think)

The Yamaha NS-10 is a near field monitor that's been one of the most widely used monitoring speakers for the past 15 or so years. The NS-10 is popular because they're a great reference for smaller consumer speakers like car audio, computer, and mini systems, and a wide range of pop recordings primarily get played back through those types of systems so the mixing is optimized for that type of playback. Yamaha discontinued it a couple of years ago because the type of wood pulp that they used in the driver is no longer available. Nowadays, Mackie seems to be the most oft mentioned near field monitor.

[Debbi]

Resurrected the circa 1974 Advents a few year back with new foam surrounds...(eventually gave them to a friends son).....Very tight bass...but very limited volume considering the power applied....they were rated at 88spl. My other impression was that they sounded like 2 isolated small bricks compared with any number of newer ported designs... the strong point was very realistic sounding drums with tight bass....beyond all that and the previous threads, there must be some reason why 90% of the speakers made in the past 10 years are some kind of ported design...I frankly dont understand the trend myself if you can make suspension speakers work well now for about the same price...I do know that the woofer cones on the Advents had tremendous visible pulsing movement, so I would assume that the useful life was shorter...

[skeptic]

There were about 4 or so principal companies which championed the acoustic suspension design although many other companies offered them too. These four all grew from Acoustic Research whose founder Edgar Vilcher invented the acoustic suspension principle. There was AR itself, KLH, Advent, and Alison Acoustics. Hard to believe but true, there was such a thing as the "east coast sound" which had a muted high end and frankly didn't have the bright dynamic qualities of the "west coast sound" championed by the likes of Altec Lansing and James B. Lansing (JBL). IMO, the qualities which differentiated them is this respect had nothing to do with bass performance but with the treble. The west coasters preferred horns which were bright but harsh and had limited dispersion while the east coast group favored cone and then dome tweeters, Acoustic Research invented the dome tweeter (and ferro fluid cooling). They based their design decisions on laboratory measurements. They also conducted several very successful live versus recorded demonstrations. For whatever reason, many people preferred a brighter sound and that is what is now in vogue.

Designing the typical audiophile speaker today is often a matter of cookbook decisions. An 8 inch woofer, a one inch Vifa, Dynaudio, or Morell tweeter, a Theil Small parameter designed 1.5 cu ft or so enclosure and a Lindquist-Riley crossover using high quality capacitors and inductors and there's your speaker. $1500 to $2500 a pair. If you want deep bass, that will be another $1000 for a subwoofer. If it's too bright, use a vacuum tube amplifier, speakers cables with very high capacitance, and a turntable with a moving coil cartridge. There's your typical audiophile sound system today. To each his own.

[NickWH]

So far nobody has mentioned NHT speakers, which are exclusively acoustic-suspension designs (barring their subs). Allison Acoustics was recently resurrected and still produces only acoustic-suspension designs.

RGA, glad to see that you are still a human Audio Note commercial, on repeat. Yawn...

[RGA]

So far nobody has mentioned NHT speakers, which are exclusively acoustic-suspension designs (barring their subs). Allison Acoustics was recently resurrected and still produces only acoustic-suspension designs.

RGA, glad to see that you are still a human Audio Note commercial, on repeat. Yawn...

Thanks I knew there was a big manufacturer still doing this and I could not rememer who the hell it was. NHT!!

There are some differences though. Audio Note only makes ONE Acoustic Suspension speaker in the K series. And the woofer is not high excursion in fact it operates not as a piston driver - and of course the drivers are closely matched which no speaker using a metal tweeter can ever be unless the woofer is metal too - and there are a few speaker recently that in fact have metal woofers - very expensive and I forget the brand name - something obscure though.

And I have decided to back off from being a walking advertisement - because it's simply too subjective - there is no right answer there is a preference. So unless the speaker fits the specific bill of a person asking a question only then will I mention them - and I will be sure to post at LEAST one other competitor hopefully 2-4+ Which is what I always tried to do before.

Besides nothing can live up to the hype anyway.

[NickWH]

Besides nothing can live up to the hype anyway.

True that.

[WmAx]

and of course the drivers are closely matched which no speaker using a metal tweeter can ever be unless the woofer is metal too

This is pretty big generalization. Do you mean most? Do you mean all that YOU have heard? DO you really mean all? Do know which specific parameters are responsible for proper integration?

"Material matching" is simply not true. The primary considerations for matching a midrange to a tweeter, for example, are:

(1) relative efficiency between the two(of course a resistor attenuation network can compensate for an imbalance)

(2) polar response at the fc(crossover frequency); both drivers should be as close as possible in their relatove dispersion at the chosen crossover point

(3) delayed energy storage - a property not correlated with frequency response, otherwise this would be linear energy storage - delayed energy storage is a characteristic created on standard drivers by two primary factors: (1) surround reflections - the sound waves will propogate at a frequency equal to the radius of the cone to the surround, the sound will reflect to and from the surround, oscillating (2) the diapgragm will usually be used in a band where it becomes non-pistonic, and not be able to be suitably damped by the voice coil motion, regardless of the source impedance presented to the VC, therfor oscillating significantly beyond the signal input decay. Some drivers effectively damp the majority of this behaviour with special diaphgrams or other unique operating principles (Focal W, K series, Linaeum, Manger, Impact/Airfoil, etc.). Some drivers simly attempt to operate within a band that they remain pistonic(mostly). Some drives are intentionally operated and/or used in passband that they are resonant, in ordet to use the 'coloration' as a signauture, tec. It is necesarry to match drivers that have somewhat similar delayed energy characteristics, at least throught he main passband at and around the crossover. Otherwise, a dis-similar sound could possibly be detected. A sudden shift of a mid to tweeter, with drastic different behaviours near the crossover points, would equate to a incoherant sound integration. It may seem to you that metal/metal combination match, becuase metal drives are usually operated compltely within their pistonic bands, with little to no resonances at and around the crossover frequency to the tweeter. Most paper-based speakers and poly based speakers have high levels of dealyed resonant behaviour in the used passband. Therefor, it is pluasible that these could often sound incoherant matched with a metal tweeter - which usually h ave a clean CSD responst up past 15kkz----some over 20khz, as compared to most fabric based tweeters which have signicant anamolies starting around 7khz. The Q, or width, of the resonances is larger with fabric/poly transducers, too, as opposed to the narrow inflection of metal drivers. It is really dependant, though. Some select fabric tweeters have responses as clean as good metal tweeters.

Bottom line is that most mixed designs may very well sound incoherant(I don't have statistical data on this phenomena), but this is certainly not a universal truth. A properly designed loudspeaker can have mixed diaphragm materials and sound coherant. It is a matteer of proper engineering.

-Chris

[skeptic]

"and of course the drivers are closely matched which no speaker using a metal tweeter can ever be unless the woofer is metal too "

To truely match a woofer and tweeter, the first thing that would have to happen is that they should be mounted coaxially. If they are not, the mere fact that they are at different locations would mean that there would be interference patterns at every point in any room in the general frequency range where their respoinses overlap. Secondly, the faster driver would have to be fed a time delayed signal so that the two drivers produced vibrations that exactly coincided in time and space. To do that, the system would of course have to be biamplified and the faster driver fed with a delayed signal preferably frequency compensated. I do not know of a single example of any loudspeaker commercially available configured this way. On the bright side, as far as I know, nobody has ever demonstrated that this would yield a better or more accurate sounding speaker.

[hertz]

Hello Sound fans:

I have this memory of my youth (the 80's)of this small acoustic suspension speakers that had the most tight bass response ever....they were japanese -Technics SB-F2 (2 way)- placed on this small tripods.

Maybe the hard wood floor had a lot to do too with it and not too many furniture in that room, it was perfect.....ahhh what a memories.....


Later in the 90's my roommate had this old tower Technics (4 way), bass reflex this time, that sounded awesome with his old silver Kenwood Amplifier and Onkyo CD changer.

Are japanese speakers very good or they just fit my ears?


Any one with comments about this two types of speakers (Bass Reflex vs. Acoustic suspension) and japanese speakers???


Thank You

Most Japanese speakers are best avoided.While they make a lot of "HI FI" sound, the manufacturers are not too bothered with the finer aspects of sound reproduction.Typical problems are poor crossover implementation, bad driver integration, shrill highs, disjointed mids and highs, slow woofers resulting in wooly bass, inability to image properly etc...

[Debbi]

If there were a truly superior speaker out there made from readily available materials ( that probably includes 99%), the larger companies could buy a pair and recreate them over the weekend....makes you wonder....auto companies already hit the design wall and thats why most of them look about the same....the wind tunnel dictates a design that 95% of the cars come close to ....I would like to think that some of these products have a "soul" for the extra buck paid, but beginning to look at speaker purchases like my shoes...."what name do you want on the product"?

[RGA]

If there were a truly superior speaker out there made from readily available materials ( that probably includes 99%), the larger companies could buy a pair and recreate them over the weekend....makes you wonder....auto companies already hit the design wall and thats why most of them look about the same....the wind tunnel dictates a design that 95% of the cars come close to ....I would like to think that some of these products have a "soul" for the extra buck paid, but beginning to look at speaker purchases like my shoes...."what name do you want on the product"?

Maybe it's about truly different than truly superior. There are rights to designs as well. For years Sony touted Trinitron as the superior picture tube all else sucked. Well the patent ran out and nobody jumped on it.

In the case of Audio Note they purchase the rights to what they like and tweak them. Their turntable which gets raves is simply a modified SystemDeckII and a Rega 250Arm with AudioNote Silver wiring their own cartridge for a budget price. Their second from top end turntable is a Voyd who went out of business.

Mr. Qvortrup and crew OWN some of the best spekaers available - looked at how to make them sound better and chose Snell. Granted a big reason would no doubt be because they dislike the sound of horns and needed something SET friendly. That alone would cut the options - though their SETs are fairly high powered actually - not the 5 watt variety.

The good stuff that was already good in the 1970's should still be good today - the low end is better today than the low end was then though. But you got more bass back then as Skeptic notes. But I would rather a good sounding speaker that misses the last 1.5 octave than a horrible speaker that produced the whole range - bass costs a lot then or now. For $2500.00 the AN E is a full range 2 driver standmount speaker which will produce to 12hz. That's about as good as it gets for the price and size.

Also:
The reason others don't simply copy is because most people want a cool LOOKING speaker - and that unfortunately is not Audio Note or Snell(which is why Snell changed from the original models to make worse sounding speakers but better looking ones - and sales went up - it's a business not a toy for many companies after all).

[skeptic]

The real truth is that like in most businesses, there are no secrets in this business either. Most advanced hobbyists and all real pros could reverse engineer any product on the market. And among the hobbyists, some of them do just that. Even paying retail for the parts, most loudspeakers can be built for a fraction of the cost of buying them already assembled by the manufacturer. The exceptions are those that use parts that have been exclusively manufactured for a particular brand. As I have posted elsewhere, IMO this is not done for any particular technical reason but to prevent people from "rolling their own" and also to have exclusive control over repair. In the past, there were drivers for which no comparable parts were available. These included speakers like Acoustic Research and KLH especially in the early days. You may also find it impossible to obtain one of a kind types like EMIT tweeters and EMIM midranges. But most loudspeakers are made from off the shelf products that you can buy yourself.

One speaker I aspire to build one day, JBL Paragon D44000 is interesting in that by the manufacturer's own reckoning, of the approximately 1000 built over the many years of production, no two were exactly alike. The people who made them had the whole thing in their heads. The manufacturer claims there are no plans in existance anymore but once in a while you'll see them offered on e-bay for about $250.