Which speakers have rear firing speakers and how do they sound?

Isn't this the core issue that people debate

A. Box speakers with front facing speakers are "more accurate - distortion free.

B. Electrostatic, bipolar, open baffle and omni speakers are less accurate with sound coming not only from the front but the back or top - e.g. have distortion built in

But in reality, when you hear live music, there is all sorts of distortion in any hall, though typically the sound is better in say the orchestra at the Beacon in NYC or the Capital in Port Chester than in the balcony. 

So, jump in and tell me how I'm wrong, but my experience is that speakers that are designed to replicate this kind of distortion sound more live. E.g. the Thiel, KEF, Canton and Proac speakers I've owned sound great but less live and less engaging than electrostatics or omni or bipolar designs. 

So, in search of the most live sounding speaker - suggestions?

Tomic601 wrote: " ... the rear firing tweeter is 100% distortion, but in some cases pleasing."

I can certainly understand how the energy going off in other directions from any polydirectional speaker can be interpreted to be "100% distortion". It’s not on the recording, right? It just adds more of the room’s sound to what was on the recording, right? And "distortion" is certainly how a measurement microphone would see it!

Let me suggest looking at this from a completely different perspective, and along the way we will discover why this "distortion" is "in some cases pleasing".

There is a vital difference between ears and microphones: The ear differentiates between the first-arrival sound and the subsequent reflections, and a measurement microphone does not.

So let’s approach speaker design from this perspective: Let’s see design for the ears instead of for microphones.

In any non-anechoic space, the ear detects two events: The first-arrival sound, and the reverberant sound (the reflections). What we actually PERCEIVE is a combination of these two events. And the less discrepancy between the two, the better the perceived sound quality.

So if we are designing for ears instead of for test instruments, we would want the reflections to sound a lot like the first-arrival sound. Since most speakers beam in the top end, this can mean adding a rear-firing tweeter to put a bit more top-end energy out into reverberant field. Fortunately the ear is not very sensitive to time coherence in the reverberant sound, so it doesn’t matter that the reflection path for the rear-firing tweeter is different from the reflection path for the main tweeter.

Thus while that rear-firing tweeter’s contribution looks like distortion to our test instruments, it results in a more natural sound because not only can the ears tell what is first-arrival sound and what is reverberant energy, but also they BOTH matter.

So, assuming competent implementation, is the rear-firing tweeter’s contribution a "distortion"? In my opinion, only if we listen through test instruments instead of through ears.

Just for the record this post is by no means a complete examination of the subject, and I have nothing against microphones as design tools.

Duke

Duke...nicely thought out BUT in the case of an acoustic event recording in the space a nicely placed microphone captures first arrival and subsequent arrivals, that information IS encoded in the wave form over long periods of time, well past first arrival.  So if the bounce is already in the waveform, why add another off the back wall ? I have in 3 rooms now tested the rear tweeter on the Vandy 5a, while I dont generallt prefer it, there are some combinations of room / recording where it sounds better. In general overdamped rooms and IMo over mic’d DG recordings. In those rooms a 2 L suffers w rear tweeter on. Just my buck fifty, but this is psycho acoustics at it’s best, imo

best and again congrats on the Subwoofer award, cool

I should clarify, a 2L “ the Nordic sound “ recording, but substitute in any good hall ambience / instrument balance recording, of which there are multitudes...

@tomic601 wrote: " Duke...nicely thought out BUT in the case of an acoustic event recording in the space a nicely placed microphone captures first arrival and subsequent arrivals, that information IS encoded in the wave form over long periods of time, well past first arrival. So if the bounce is already in the waveform, why add another off the back wall ? "

Excellent question, goes right to the heart of the matter. Unfortunately my answer is not going to be as succinct.

When we listen to recorded music, there are TWO venues in play: The FIRST venue is what’s on the recording (whether it originated in an actual acoustic space or was synthesized by the engineers). The SECOND venue is the room we listen in. At the risk of oversimplifing: FIRST venue GOOD, SECOND venue BAD.

So we want to the first venue cues to be effectively presented, and the second venue cues to be as innocuous as possible.

An effective presentation of the first venue cues would have them come from all around, which implies having a lot of reflections. Also those reflections should have a spectral balance that mimics the first-arrival sound - when they do not, they are more likely to sound unnatural.

So, by correcting the spectral balance of the reverberant energy via a rear-firing tweeter, we are making the second venue cues less obtrusive.

But, we need to look at the time domain as well. The relatively short reflection path length of that rear-firing tweeter makes is an early reflection. And we know from the experience of countless Maggie owners that rear-firing energy sounds good when there is a long time delay, and bad when there is a short one (clarity is degraded and second venue cues are emphasized). So with speakers close to the wall a rear-firing tweeter may not always be a net benefit.  Having spent a fair amount of time working with secondary arrays of drivers, I try to aim them in a direction that results in a relatively long reflection path length.

This long path length for the additional reverberant energy has an unexpected benefit: It makes the second-venue cues weaker!

Let me explain: The ear judges the size of a room by the time between the first-arrival sound and the "center of gravity" of the reflections. By injecting additional relatively late-onset reverberant energy via long-path-length reflections from additional drivers, we are pushing that center of gravity back in time, and we are making the second-venue cues more ambiguous. As a result the "small room signature" imposed by the second venue becomes less obtrusive, so it does not dominate the first venue cues as much as before. We hear more of the soundscape that is on the recording and less of whatever room we are listening in.

I don’t really expect you to believe me because this is a highly unorthodox idea being described by the guy who has a commercial interest in it. So here is my question to you: Are there any audio shows that you sometimes attend? I usually only do about one big show a year, but maybe just maybe we can cross paths at one.

Duke