Comparison of 'Xbush Sphere synergy horn', versus 'Balls of Prestige'.

I find that "detail" is usually a function of the damping of the driver at higher frequencies--particularly above 10 kHz--and the absence of diaphragm breakup modes (like beryllium diaphragm drivers exhibit in spades, but also polymer diaphragm ring radiators). If you look around for a better damped compression driver (if there are such things available in the throat size that you're using), I'd bet you could close that gap.

The deal with adding ways to a loudspeaker makes sense in terms of breaking up AM and FM distortion sidebands, and allowing you to use flatter phase crossover filters (if using IIR filtering)--like Dunlavy did on his loudspeakers using a succession of 1st order crossover filters. But the real difference is that direct radiating drivers move about 5x farther to achieve the same on-axis SPL as the same driver using horn loading, so adding extra ways reduces the AM distortion significantly, which is most prevalent at lower frequencies (according to Klippel, whom I trust implicitly on that subject).

One thing that I should state: I find that lot of people also factor in "apparent depth of soundstage image". In my experience, this usually has nothing to do with the MEH performance which is usually reproducing what's in the recording itself faithfully, except perhaps its better directivity across its pass band, but a lot more to do with reflections from furnishings and walls/ceiling/floor from loudspeakers that don't control their polars as well...and high output impedance amplifiers adding their own little "extra reverb" into the mix.

Chris
 
Last edited:
We are focusing on dispersion here, but I would say again the detail retrieval was better with the 4-way too - so I feel there is definitely some driver influence at work too. If it is just dispersion, and the 18 sound system is 'too narrow' you would expect it to 'beam' the details straight to ones ears leading to incredible unfettered details. But this was not the case.


Actually, there’s evidence that early reflections enhance dialogue intelligibility. That leads me to think they may help the human ear+brain generally extract more information (“detail”) from recordings.

If you upgrade that ring tweeter to one that’s less beamy you may hear further improvements in the 4-way. Scan has a Be one that may be a drop in replacement...
 
It is very interesting to me that we design these speakers to take the room out of the equation somewhat and then have to put it back in with diffusors and ambience tweeters!

Well, I don't thhink that's quite exactly what we're doing -- the room problem is largely (IMO) near reflections, but what we're adding back in with diffusors and ambience tweeters is late reflections, quite a different thing perceptually.

Pallas -- for what it's worth, we also noticed here that the added late reflections (they're about 20 to 25msec late by the time most of them get to our ears) also significantly improved intelligibility. So much so that we watch several episodes of a series before we noticed that the subtitles we usually keep displayed weren't on (wife has some HF hearing deficit). So maybe it's not just early reflections that can do that, but also ones that aren't so firmly in the integration period?
 
Last edited:
Actually, there’s evidence that early reflections enhance dialogue intelligibility. That leads me to think they may help the human ear+brain generally extract more information (“detail”) from recordings.
I believe that we're mixing modes here. Some early reflections help dialogue intelligibility at the time when the recording is made (i.e., controlled levels, which are actually pretty low), but not so much when it's played back.

Additionally, there is a large difference between dialogue intelligibility and "detail". In some ways, these are polar opposites of each other.

Chris
 
By the way, the Haas interval for most sounds is between 20-50 ms (and as much as 100 ms). I don't believe that we're getting "late reflections" using room treatments unless our listening rooms are at least 10-25 feet larger than the spacing of the loudspeakers--on each side of the loudspeakers. That's a pretty tall order for room treatments to fulfill. Usually, that's relegated to the surround channels of a 5.1 array.

Toole talks about this in his 3rd edition.

Chris
 
Pallas -- for what it's worth, we also noticed here that the added late reflections (they're about 20 to 25msec late by the time most of them get to our ears) also significantly improved intelligibility. So much so that we watch several episodes of a series before we noticed that the subtitles we usually keep displayed weren't on (wife has some HF hearing deficit). So maybe it's not just early reflections that can do that, but also ones that aren't so firmly in the integration period?

+1, as long as it's within the Haas limit and not perceived as a separate event (echo like).
 
---

I've found that the comment about "the exactly similar loudspeaker as L/C/R" is pretty important, as well as getting all three at the same height. The comment about "phase warp" is much less significant IME, but the flatter the phase through the crossover (a function of the low pass filters used, if IIR), the better it sounds--subtly. IIRC, the person that you're talking to has said that he has plans on using FIR filtering, so phase is probably not an issue for that application--unless it also brings pre-ringing.

Chris

I guess you mean electric phase angle of the speaker?

I was referring to acoustic phase and thus each "way" driver's polarity. Typical 2-way with LR2 xo turns acoustic phase 180¤ - so when bass is + tweeter is connected in reverse polarity. With LR4 phase rolls 360¤ and both drivers are connected in same polarity. Etc. And then we have topologies that have 90¤ phase shift.

If L/C/R have same crossover topology and almost same xo frequency, imaging will be ok. But if C has LR2 and mains LR4, center tweeter has "wrong" polarity and sound will be a mess, never right no matter what polarity or delay settings!

I have read about many HT systems that don't follow this rule, typically mains are 3-ways and center 2-way. Mission impossible, unless you use rePhase or some other FIR-eq system!
 
Last edited:
Well, I don't thhink that's quite exactly what we're doing -- the room problem is largely (IMO) near reflections, but what we're adding back in with diffusors and ambience tweeters is late reflections, quite a different thing perceptually.

Sorry I was being a little tongue in cheek there!
I quite agree the two are very different and minimizing early reflections with my enclosure designs and absorption treatments, whilst maximising late with my rear wall diffusion has been my aim too!
I totally agree with you.
 
It would be interesting to do the comparisons again, but this time EQ them to be the same outdoors, not at in room listening position. I believe the differences you are hearing are due to having more direct sound in the MEH than in the 'conventional' design. (ie: these 2 speakers should not have the same response at listening position due to their different dispersion patterns)

Rob.
 
You could be right that may be part of it. But I did do the test with the original voicings which were designed with outdoor measurements first before eqing at the LP for the second round of listening. The synergies fell short on both settings.
I really think it is a combination of factors at play.

Plus my listening room is pretty well designed with lots of absorption. The treble for both systems didn't require much change at all, it was mainly the midbass and bass which was different.
 
Regarding the bass of both systems- they are both really excellent - the synergys dig really deep with their 4x 8" woofers, whilst the 4 way system has a frankly ridiculous set of sub-woofers with massive displacement that is overkill for nearly everything.

Would be interesting to see what happens if you redo the rest with a 100hz highpass for both systems.

Also for more HF detail, forgetting about the horn for a moment: what about the SB65 vs real tweeter? Looking at the distortion plot's they should both be excellent, and even the waterfall plot of the SB is extremely clean almost up to 20K.
 
I was referring to acoustic phase and thus each "way" driver's polarity...
So was I. I have stopped using Linkwitz-Riley crossover filters as well as the related Butterworth filters because of their low-pass phase growth characteristics, in favor of low-order Bessel filters--especially with MEHs, which sum their response internally much better and produce consistent polars in the crossover band(s). Overall phase response (via acoustic measurement) with respect to minimum phase is much better, and it seems that the human hearing system likes the results of lower excess phase growth.

Trying to minimize the interference bandwidth I've found is usually not a good trade if the excess phase goes off the deep end.

Chris
 
Last edited:
...Plus my listening room is pretty well designed with lots of absorption. The treble for both systems didn't require much change at all, it was mainly the midbass and bass which was different.
You may not be aware that there is a thread in the new "Room Acoustics and Mods" section that is gathering individual listening room reverberation time plots so that some understanding of the typical (and non-typical) decay times in-room can be made more apparent, instead of everyone having to do their own guessing what their room is doing relative to others on the forum: RT60 and your listening room
 
Last edited:
...But if C has LR2 and mains LR4, center tweeter has "wrong" polarity and sound will be a mess, never right no matter what polarity or delay settings!

I have read about many HT systems that don't follow this rule, typically mains are 3-ways and center 2-way. Mission impossible, unless you use rePhase or some other FIR-eq system!
I agree with your observation that many people do not pay close enough attention to the triplet of loudspeakers across the front of a multichannel loudspeaker array and their relative phase characteristics.
 
Member
Joined 2014
Paid Member
We should not lose track of the fact the the Synergies use a £23 driver from 500Hz up. Provided one views labour as free on DIY projects that's an awful lot of performance for not much money. By comparison the volt midrange is nearly £600 list. I'm still, on consideration mightily impressed by what Bush and X did on this
 
We should not lose track of the fact the the Synergies use a £23 driver from 500Hz up. Provided one views labour as free on DIY projects that's an awful lot of performance for not much money. By comparison the volt midrange is nearly £600 list. I'm still, on consideration mightily impressed by what Bush and X did on this

Absolutely! I hope people don't think the synergies sound poor. As I have said, they are better than my other older speakers I have built and owned over the years (many!) And it was only in side by side instantaneous switching that the differences were noticeable.

Again i should underline these impressions were subjective and personal, others mileage may vary!

It has underlined to me how different designs sound very different even with similar measurements. It make me want to build line array and open baffle speakers too then I could have even more interesting listening sessions!:D
 
"It has underlined to me how different designs sound very different even with similar measurements."
Interesting thing about the ambient driver thing -- if the system is measured in the "normal" way (quasi-anechoic, with windowing terminating the impulse response somewhere before 10msec) the frequency response measurement is for all practical purposes identical with or without the ambient driver playing. Yet even my HF hearing impaired wife can hear an unquestionable difference (maybe even "from the kitchen"!)
 
To see rear tweeter's effect with REW it is best to look at signal decay with long enough time window (use Decay, CSD or Spectrum window).

NeoB is same speaker with rear tweeter added. On axis is not same but look at how treble decay vs. on-axis changes! Measured almost 5 years ago, published also in my signature thread.
 

Attachments

  • ainogneob v2 vs neo v11 0¤ decay csd.png
    ainogneob v2 vs neo v11 0¤ decay csd.png
    761.5 KB · Views: 285