getting all misty-eyed over Bose 901's

[jdm56]

I can't be sure about your model, but the eq with the Series IV's I owned just hooked up in the tape loop. It could also be plugged in between the pre and power amps. The current models still work this way.

[jdm56]

"Fundamental to this increased understanding was the critical detrimental effect caused by the early arrival reflected signals upon intelligibility. And the Bose direct-reflecting models were specifically designed to intentionally add to the early reflected signals! Sure they made the sound bigger, but they did so by destroying the distinct imaging and intelligibility of the signal."

-dragonfyr

Well yeah, but...if "intelligibility" was the holy grail, we'd all be listening to music in anechoic chambers! The reproduction of music in the typical small-room environment often benefits from some enhancement of the reverberant field's role in the overall acoustic.

Gosh, I really didn't intend to be defending Bose here, but I do find a lot to like with the current 901, and I feel there is sound engineering behind it's basic design. Which is not to say I think it is the best speaker going, but in certain areas of performance, it is very good for it's size and price. There is also sound engineering behind the klipschorn, yet Bose and Klipsch take practically opposite approaches. I guess there's more than one way to skin a cat, eh?

[homemade]

I built an original 901 from the patent papers that speakerlab had in the mid 70's. I never did have the proper eq. (there was an eq. schematic in the patent papers) but used a 10band eq. which worked fine. You had to increase the lowest 2 octaves 12db (I also had to eq. the lowest octave on the mighty khorn also) and upped the highest band eq. by 12db (15khz). They were ok but the bass still lacked for me. Nowadays one would just add a subwoofer to fix the lower end problem. The early models (before the plastic housing models) were touted as low effeciency but really the midrange was very effecient (I would put it into the 95 db range-all the coupled drivers helped I guess). For a small speaker they were ok. Most bass at the lower octaves weren't that powerful anyway and most of the music energy falls into the 100hz range which is were they were very efficient. I think I finally added a piezo horn tweeter to sweeten the highs and like I said earlier-a good subwoofer would work wonders for the low end. No eq. would be needed if one added the sub and tweeter. The midrange wasn't as articulate and detailed though as a horn would be. I would think the current 901's would work great in a theatre setup. Bose used to market some recievers with built-in eqs for the newer series. Specs on the recievers were ok and power output in the 40wpc range. Not enough for the older series but probably ok for the newer ones.

[jt1stcav]

I don't know what to think of Bose products. What I've heard over the years never really impressed me much, although I do have a brother who bought a pair of 301s way back in '84 that he still uses today, albeit for surround duty now with his Polk Audio mains/center for his HT.

When I was stationed in Germany back in '83, I wanted a pair of Cornwalls real bad, but the PX in Stuttgart was sold out with no replacements in sight for the foreseeable future. They just sold their last pair of Heresys and they stopped carrying Belle Klipsch and La Scallas. I needed a pair of decent loudspeakers, and I didn't care much for their other loudspeaker selections (or they were totally out of my budget), but I could afford either the JBL L112 Century II monitors, or the Bose 901 (Series ?). I critically auditioned both pairs, and I even had the salesman place the loudspeakers in various areas of the all-glass showroom for best placement. No matter where they were, I couldn't hear any significant improvement with the Bose, and in all cases the JBLs simply blew the Bose away in terms of clarity, depth, and 3D realism! To my ears, the Bose 901s were not all that they were cracked up to be, and I was highly disappointed with their lack of bass. I took the L112s back to the barracks with me that day, and jammed with them for over 17 years until I bought a pair of inefficient but realistic sounding Magnepans!

I've lost track with Bose consumer loudspeakers over the years...with so little interest in 'em I just couldn't be bothered anymore. Since I've been employed with Guitar Center we recently started carrying their pro audio packages, their big news being the Bose Personalized Amplification System ( http://www.bose.com/controller?event=VIEW_PRODUCT_PAGE_EVENT&product=l1_single_live_music ), which consists of the L1 Cylindrical Radiator loudspeaker and PS1 power (amplified) stand, one R1 remote control, and one (or more) B1 bass modules. I've never heard this system in a true live concert environment, but I have heard them being auditioned by guitarists and keyboard players, and at least in the "live room" in our store their sound is pretty amazing! They don't seem to overpower the musician who's playing through them, yet they're plenty loud enough to fill the room with clean, clear sound...they're supposed to have won numerous awards for their breakthrough design, and we can't seem to keep enough of 'em in stock. As soon as I receive another batch, we turn around and sell them all!

I still don't know what to make of Bose, but they do seem to be doing something right. Love 'em or hate 'em, Bose is here to stay!

[dragonfyr]

"Fundamental to this increased understanding was the critical detrimental effect caused by the early arrival reflected signals upon intelligibility. And the Bose direct-reflecting models were specifically designed to intentionally add to the early reflected signals! Sure they made the sound bigger, but they did so by destroying the distinct imaging and intelligibility of the signal."

-dragonfyr

Well yeah, but...if "intelligibility" was the holy grail, we'd all be listening to music in anechoic chambers! The reproduction of music in the typical small-room environment often benefits from some enhancement of the reverberant field's role in the overall acoustic.

Nope!!!! Totally incorrect!

NO acoustically knowledgeable person aspires to having an anechoic chamber for a listening room! But such is a common misconception that so many adhere to as they dismiss the advances of the last 35 years of acoustics!

That is not the point of controlling the EARLY reflections!

And there is NO reverberant field in a "small" acoustic space! By definition!

But removing the early reflections and controlling the late reflections in a 'well behaved' fashion is critical to optimal listening.

And the Bose 'direct - reflecting' concept violates all of what we now know about this - both acoustically and pyschoacoustically. Which I have no problem with, given the understanding of acoustics when they were first introduced! But at some point as we learn, kids are supposed to evolve and mature! Not just pile on more marketing dollars!

And jt1stcav hit the nail on the head regarding Bose!!!!

"No matter where they were, I couldn't hear any significant improvement with the Bose"

If you look at a field intensity plot, Bose exhibits a chaotic field - no where is it particularly good - it is a rather homogeneous mediocre field. So that as you move from one spot to another there is no radical change from good to bad! And that has become the MAIN selling point as the sound stage seems to be much wider then with most! Of course nowhere is it good, but you never notice a distinct change to 'bad'.

That is the fundamental difference between the BOSE experience and a more sophisticated system.

Lots of money for mediocrity!

[jdm56]

"And there is NO reverberant field in a "small" acoustic space! By definition!" --dragonfyr

"There are those who feel it is improper and inaccurate to apply the concept of reverberation time to relatively small rooms. It is true that a genuine reverberant field may not exist in small spaces. Sabine's reverberation equation is based on the statistical properties of a random sound field. If such an isotropic, homogenous distribution of energy does not prevail in a small room, is it proper to apply Sabine's equation to compute the reverberation time of a room? The answer is a purist "no", but a practical "yes".Reverberation time is a measure of decay rate...Whether the sound field is diffuse or not, sound decays at some particular rate, even at the low frequencies at which the sound field is least diffuse. --F. Alton Everest, from THE MASTER HANDBOOK OF ACOUSTICS, 3RD EDITION

And jt1stcav hit the nail on the head regarding Bose!!!!

"No matter where they were, I couldn't hear any significant improvement with the Bose"

If you look at a field intensity plot, Bose exhibits a chaotic field - no where is it particularly good - it is a rather homogeneous mediocre field. So that as you move from one spot to another there is no radical change from good to bad! And that has become the MAIN selling point as the sound stage seems to be much wider then with most! Of course nowhere is it good, but you never notice a distinct change to 'bad'.

I do believe Bose' intent with the 901 was to generate a "homogenous" and "chaotic" sound field. They call it "Stereo Everywhere". The idea being to more closely mimic the ratio of reflected to direct sound heard in a live concert setting. And in the process, create a bigger sweet spot. -Not a bad goal! And one they are not alone in pursuing. Mirage, Definitive Technology, Martin-Logan, Magnepan and Quad, among others have chosen the same basic path, even though each has their own unique vision on how to achieve it.

[dragonfyr]

"And there is NO reverberant field in a "small" acoustic space! By definition!" --dragonfyr

"There are those who feel it is improper and inaccurate to apply the concept of reverberation time to relatively small rooms. It is true that a genuine reverberant field may not exist in small spaces. Sabine's reverberation equation is based on the statistical properties of a random sound field. If such an isotropic, homogeneous distribution of energy does not prevail in a small room, is it proper to apply Sabine's equation to compute the reverberation time of a room? The answer is a purist "no", but a practical "yes".Reverberation time is a measure of decay rate...Whether the sound field is diffuse or not, sound decays at some particular rate, even at the low frequencies at which the sound field is least diffuse. --F. Alton Everest, from THE MASTER HANDBOOK OF ACOUSTICS, 3RD EDITION

Amazing. so that since sound intensity decays it is reverberant.

The problem with this rationalization is that it ignores the fact that words mean things. And while convenient, it is not useful to simply define new meanings simply to assuage one's emotions, eg. Bill Clinton!

And while normally pretty good, Everest butchers the meaning of the terms he uses, redefining them at his convenience into cocktail party dalliance. He dismisses their defined meanings and simply ignores them. It's not often, but Everest falls flatly on his face here!

So here is the physics regarding "genuine reverberent fields" to which Everest chooses to ignore , rather preferring Everest's contrived "non-genuine reverberent fields" of his quaint cocktail party definition that defines any decay in sound intensity as "reverberation":

From Sound System Engineering, Davis & Davis (p.211-212):

To quote Ted Schultz (formerly of Bolt, Beranek, & Newman):

"In a large room, if one has a sound source whose power output it known, one can determine the total amount of absorption in the room by measuring the average pressure throughout the room. This total absorption can then be used to calculate the reverberation time from the Sabine formula. This method fails badly in a small room, however where a large part of the spectrum of interest lies in a frequency range where the resonant modes of the room do not overlap but may be isolated....In this case the microphone, instead of responding to a random sound field (as required for the validity of the theory on which these methods depend), will delineate a transfer function of the room...It does not provide a valid measurement of the reverberation time in the room."

What is often overlooked in the attempted measurement of RT60 in small rooms is that the definition of RT60 has two parts. The first part is unfortunately commonly overlooked.

1.) RT60 is the measurement of the decay time of a well-mixed reverberant sound field well beyond D(subC).

2.) RT60 is the time in seconds for the reverberant sound field to decay 60dB after the sound field is shut off.

In small (acoustical spaces) there is no D(subC), no well mixed sound field, and hence, no reverberation. There is merely a series of early reflected energy. Consequently, the measurement of RT60 becomes meaningless in such environments.

The control of the early reflections becomes most meaningful because there is no reverberation to mask them."

.....

Schultz has also developed a new empirical equation for predicting the sound pressure level (LsubP) in non-diffuse sound fields indoors - a A New Level Equation for Small Nonreverberant Environments. He again reminds his listeners that "no uniform reverberant sound field occurs in normally furnished dwelling and office spaces."

And rather then copy several pages of stuff that few will read, may I offer the information to anyone so interested by PM request regarding the:

Schultz Equation(s), as well as a comparison of the Schultz Equation with the Hopkins-Stryker Equation plus the Puetz Add-on Expression. The agreement between the two is stated to within 0.77 dB (95.27 - 94.5).

Funny, I couldn't find any Everest equations regarding the definition or behavior of either "genuine" or contrived reverberant fields!

But you can buy his book and discover that the intensity of a "sound decays at some particular rate, even at the low frequencies at which the sound field is least diffuse." Wow!...At any rate, pick a rate, as ole Everest can't begin to tell you! Duh! Any more profound and startling insights!?

Whatever, but it is not a reverberent field!

One of the defining characteristics of a "small acoustical space" (as distinct from a "large acoustical space" ) is the absence of a reverberant field!

And jt1stcav hit the nail on the head regarding Bose!!!!:

"No matter where they were, I couldn't hear any significant improvement with the Bose"

"If you look at a field intensity plot, Bose exhibits a chaotic field - no where is it particularly good - it is a rather homogeneous mediocre field. So that as you move from one spot to another there is no radical change from good to bad! And that has become the MAIN selling point as the sound stage seems to be much wider then with most! Of course nowhere is it good, but you never notice a distinct change to 'bad'. - Dragonfyr

I do believe Bose' intent with the 901 was to generate a "homogeneous" and "chaotic" sound field. They call it "Stereo Everywhere". The idea being to more closely mimic the ratio of reflected to direct sound heard in a live concert setting. And in the process, create a bigger sweet spot. -Not a bad goal! And one they are not alone in pursuing.

Thank you. That is why I mentioned it!!!!! And as mentioned, at the time they (Bose) introduced it, it seemed like an advancement. As I was generous in acknowledging, it was not a bad goal! Just a flawed implimentation! But further advancements in knowledge have shown the concept to be fundamantally flawed. The result is a larger area of mediocre response, regardless of what they choose to call it!

The fundamental problem being that it still violates the behavior and conditions that they were hoping to recreate! And while their design may have had the purest of intentions, the concept is nevertheless fundamentally flawed! Maybe I should mention once more that the concept is 'fundmentally flawed'! Attempting to use large acoustical space concepts (such as the existence of a reverberant field) in a small acoustical space characterized by specular reflections and room modes that violates the fundamental requirements for a reverberent field is a flawed design. And it is not "valid", regardless of their erroneous intent!

Thus I seem to be back at square one repeating my original assertions! And also reasserting that respectable organizations tend to improve upon designs based upon additional information and improved methods. But some do not!!!

I am of the camp that believes that it is advantageous to incorporate increased knowledge and to improve designs to capitalize upon such increased knowledge. But then I suppose I may be a bit unusual in this regard. Certainly Bose disagrees with this radical philosophy!

And one wonders why Dr. Bose was so adamant against having the Indiana University Field House test results published in a comparative study between the various approaches, two featuring controlled dispersion (Q) minimizing overlap of adjacent sound fields, and the third approach featuring the Bose 'what the heck does Q have to do with it' philosophy! And this, the SAME company who sued Consumer Reports for not rating their speaker number one! Go figure!

You are by all means welcome to do things as you choose. After all, it doesn't impact me as I don't have to listen to it! But please do not interpret that to mean that we cannot evaluate the design objectively simply because some still prefer the older methodology based upon a flawed foundation, or that others acknowledge the meaning of words and then proceed to redefine them to say anything they choose! Bottom line: the 'direct-reflecting' concept is flawed and can be demonstratively and objectively verified both quantitatively and qualitatively.

[jdm56]

It seems to me a gross oversimplification to flatly state "small rooms have no reverberation." The obvious implication is that large ones do have reverberation. Which of course is true, but exactly what are the magic dimensions below which a room has no reverberation, yet above which, it does?

It would further appear that any measured decay time in any size room, that is longer than what would be observed under anechoic conditions must be due to reverberation. You can call it "merely a series of early reflected energy", but it's the same thing --sound bouncing around the room!

Regarding Bose' scientific theory behind their direct/reflecting speakers being flawed, well yes, I don't think even Bose would seriously claim they have perfectly reproduced the sound of a live musical event with their 901's. I recognize advertising hyperbole for what it is. And I assume most other people do too. Still, the technology is valid, if certainly not perfect. It is mainly limited by the dimensions of most home listening rooms, which are too small to allow enough delay between the direct sound and the reflected sound, which as you say, does tend to make sonic images bigger and more diffuse than they would be with conventional monopolar speakers. Of course, interestingly enough most live sound is also bigger and more diffuse than that reproduced in typical home listening rooms with conventional speakers. Go figure.

[Petrol]

ROFLMAO

[dragonfyr]

A classic example of trying to debate a topic with someone who has absolutely no idea of what is meant by the proper use of the terms employed!

After all, where else can you encounter illogic like:

"it's the same thing --sound bouncing around the room!"...

all reflection is reverberation...

therefore, all sound is reverberation.

The irony is that he doesn't have a clue as to how a reverberant sound field is defined! So of course "it's (all) the same thing!"

And as far as "magic" dimensions...!

Go examine the "magic" characteristic defined as "critical distance"...

And no, this is not a dimensional ratio! For that you want Bolt, Baranek,& Newman's Acceptable Room Ratio Chart.

If anyone wants to discuss small and large space acoustics it would be a welcome encounter. But please at least begin by reading chp 7-9 of Sound System Engineering, 2nd Ed. by Davis and have a basic grasp of some of the concepts - or at least, what a couple of the fundamental terms mean - or heck, at least, a reliable reference where you can go to refresh your memory!

[feersum dreadnot]

When I was stationed in Germany back in '83, I wanted a pair of Cornwalls real bad, but the PX in Stuttgart was sold out with no replacements in sight for the foreseeable future. They just sold their last pair of Heresys and they stopped carrying Belle Klipsch and La Scallas. I needed a pair of decent loudspeakers, and I didn't care much for their other loudspeaker selections (or they were totally out of my budget), but I could afford either the JBL L112 Century II monitors, or the Bose 901 (Series ?). I critically auditioned both pairs, and I even had the salesman place the loudspeakers in various areas of the all-glass showroom for best placement. No matter where they were, I couldn't hear any significant improvement with the Bose, and in all cases the JBLs simply blew the Bose away in terms of clarity, depth, and 3D realism! To my ears, the Bose 901s were not all that they were cracked up to be, and I was highly disappointed with their lack of bass. I took the L112s back to the barracks with me that day, and jammed with them for over 17 years until I bought a pair of inefficient but realistic sounding Magnepans!

Sounds familier - When I was at the Naval Academy, I started with a set of Celestion Ditton 110s, an Adcom GFA-1a, GFP-1 and GFT-1 (200 w/ch amp, pre-amp and tuner, respectively). I quickly blew the Celestions - they would have been good for an adult, not a midshipman that liked to rock. Went down to the mid-store (our version of the on-base exchange), and listened to the JBL L112s and the Bose 901s. Bought the L112s, which survived until a very loud and prolonged party in 1986.

Then I bought the Fortes, and they have been a constant companion since then, adding another pair and an Academy this summer.

Nothing like efficient speakers to make up for limited amplification...

[jt1stcav]

Oh yeah, the L112s could definately rock the house!

I recall the numerous "GI Parties" where we'd clean the entire barracks form top to bottom...my room was at the very end of the 40 yard building, and my buddies at the very opposite end of the building could clearly hear me playing "Highway to Hell" and "The Song Remains the Same" at 120dB (with my Carver M-400t "cube" 201 WPC amp, C-1 preamp, TX-11 tuner, and Nakamichi DRAGON 3-head cassette deck)!

Ah, memories...[<)]