Stereo Crosstalk Elimination (reduction) Par Excellence!

[Tim Link]

Further experimenting with my new room has led me back to my earlier configuration with spacing about 1 foot apart center to center, and listening position about 8 feet back. This seems to be close to ideal and produces a very wide, well separated sound field that reminds me most of using a physical sound barrier, which is still the best. An additional important factor is to have the speakers out in the open, off the back wall a bit, not tucked inside a cabinet like I had them earlier.

 

[Tim Link]

I've finally taken this setup to fully horn loaded. No more bookshelf speakers doing surrogate duty. I resisted trying this because I didn't have three horns that were the same so I figured it wasn't likely to sound very good. But after enough dissapointment at the sound I could get from the high dispersion (relatively speaking) M16s I decided to give the horn tweeters a try. I had already pushed the crossover point up to 800Hz, which was as high as I could go with the three speaker array and still maintain the crosstalk effect. The horns were just winning overall in any frequency range I could give them.
Now that the tweeter horns with compression drivers are doing duty above 800 hz the difference is amazing and unexpected. I thought it might sound too dead because of their very narrow dispersion up high but that is not the case. The sense of liveliness and airiness is much higher with the horns. The ability to play loudly is of course amazing, but so is the ability to be heard clearly at very low volumes. So I'm once again a confirmed horn guy, even with my 3 speaker crosstalk elimation array, and even though my horns don't match. I was able to EQ them closely enough so the stereo widening effect is very strong. I'm thinking about buying another horn and compression driver to get three that match but it sounds so good I'm not inclined to complain. I still don't feel I have a firm grasp on exactly what it is that is going on with horns that makes me like them so much. Direct radiators just seem to have a fog bank around them that I don't hear directly but notice it's disappearance when a good horn setup is put in their place. The direct radiators always surprise me with how good they sound and measure but the horns are just a whole different level for me.
So one good take away from this even if you don't like horns is that the 3 speaker array can be limited to 800Hz and above - sort of a center tweeter array, with all the lower frequencies played back in standard stereo and it can sound really great.

Bass horns are doing 20 to 300Hz. Mid-bass horns (black boxes nestled between the bass horns in the wooden columns) are doing 300 to 800Hz - just bridging the gap. Tweeters cover 800 on up. I can get the bass horns to go all the way up to 800 but I give up a lot of headroom to do that.

One downside to this is tweeter hiss. The compression drivers are of course super efficient so I can hear my Denon's noise. It's a very worthwhile tradeoff.

 

[tmuikku]

^Hi, have you experimented at what listening distance the direct radiators start losing to horns/waveguides?

From the picture you seem to have naked sidewalls. Also ceiling and floor seem reflective and I suspect you probably have flutter echo which ruins intelligibility, more so with direct radiating speakers than with horns / waveguides.

Well, at least I think its something in direct / reflected sound ratio that makes the difference between nice clear sound and something that is less accurate, veiled in a way. More specifically I think its flutter echo than any other small room phenomena / problem that makes it first and foremost. I've got waveguide speakers but still cannot extend the magical accurate sound all the way to practical listening position, to the sofa. The sound gets "veiled" so to speak little before, which I contribute currently just to direct / reflected sound ratio being too small at sofa, before knowing more accurately what actually contributes to it. I'm saving up for some acoustic panels to experiment with and expecting acoustic treatment would (eventually) extend the clear sound all the way to the sofa, starting with killing the flutter echo. There is some flutter echo currently detectable with simple hand clap test so I suspect that is the most audible issue also with stereo playback in this regard.

Anyway, its probably just ratio of room size to listening triangle size and position that makes waveguides more desirable than direct radiators so was interested if you have any insight to this. Thanks

 

[Tim Link]

^Hi, have you experimented at what listening distance the direct radiators start losing to horns/waveguides?

From the picture you seem to have naked sidewalls. Also ceiling and floor seem reflective and I suspect you probably have flutter echo which ruins intelligibility, more so with direct radiating speakers than with horns / waveguides.

Well, at least I think its something in direct / reflected sound ratio that makes the difference between nice clear sound and something that is less accurate, veiled in a way. More specifically I think its flutter echo than any other small room phenomena / problem that makes it first and foremost. I've got waveguide speakers but still cannot extend the magical accurate sound all the way to practical listening position, to the sofa. The sound gets "veiled" so to speak little before, which I contribute currently just to direct / reflected sound ratio being too small before knowing more accurately what makes to it. Saving up for some acoustic panels to experiment with and expecting acoustic treatment would (eventually) extend the clear sound all the way to sofa. There is some flutter echo here with simple hand clap test so I suspect that is the most audible issue also with stereo playback in this regard.

Anyway, its probably just ratio of room size to listening triangle size and position that makes waveguides more desirable than direct radiators so was interested if you have any insight to this. Thanks

Your thoughts are very much the same as mine. I suspect it has much to do with direct to reflected ratio. I sell acoustic treatments and I tried some in here. They really weren't the right ones for this space but they were just sitting around and available for me to take home. They noticably improved the imaging but the room was already sounding a bit overdamped and they just made it more so. The RT60 is lower than 0.3 over much of the frequency band in here, specifically up in higher frequencies. I have a carpet in here and I'm wondering if I should have put in a hard floor instead. TubeTraps would be more helpful because they reflect and diffuse treble while absorbing lower mids and bass.

I don't notice any flutter echo in this room. I think early reflections the problem because they reach me too soon. i can see them clearly on the spectrograph. With the big horn tweeters they're barely visible. A small room can make things tough. Having a big screen TV right behind wide dispersion speakers probably isn't great either. It's much less of a problem with large horns that can keep most of the sound moving toward the listener. The somewhat unintuitive result is that huge horns in a little room make the room seem bigger and more lively and reverberant by delaying and attenuating the first significant reflections to reach the listener while maintaing a long enough reverb tail.

 

[tmuikku]

Yeah its a tough one as forums are full of posts about problems of small room acoustics, while most scientific research is on bigger rooms like concert halls. Also the adjectives describing various audible phenomena are hard to understand how they translate to actual perceived sound before formal/self training. Its also almost impossible to know what others mean with the words, how they perceive/describe the phenomena

I'm taking this topic to discussion as I've observed that studies often mentioned in threads like this https://www.audiosciencereview.com/...lections-isnt-there-a-price-to-be-paid.16687/ seem to attach positive and neutral adjectives to early reflections like "wider sound stage" or "spaciousness" and "change in timbre" and so on, not negative like "veil" or "fog bank" we used here There is also studies (example) that suggest early reflections Increased intelligibility (of speech) for example, which also indicates to me being positive and opposite description to veil / fog at least how I interpret the stuff.

From this I would reason, as hobbyist, that the singular first reflections are not very important as such but as more reflections come in something happens that makes a "fog".

I'm with you that its probably easy to have the room too much damped and lose spaciousness. I'm battling it with as well in a way. The acoustics seem nice in our living room just by the average living room furnishing. Spaciousness is fine with stereo setup but I'd like more envelopment which probably means wider coverage speakers and less absorption would work better but I'm afraid this would reduce the clear sound distance even more, wouldn't help with the fog which is about the biggest issue currently on my setup. I suspect it would be even more veiled sound at the practical listening position some 2.5/3m away.

The flutter echo seems to fit nicely in the picture contributing to the "fog" and suggests convenient solution for a living room acoustics which is: besides normal furnishing in the room use acoustic treatment only to treat the flutter, if any. This means keeping the corners and most of the surfaces reflective, utilize suitably narrow directivity system and perhaps resort to multiple sub solution to overcome need for bass traps.

There is quite little discussion on flutter echo so wanted to bring it up if someone has first hand experience on it, on the "fog".

 

[Tim Link]

I'm trying out a speaker loaned to me from my local dealer. It's a Revel Concerta LCR8.

LCR8 | Concerta Series, 3-Channel, LCR On-Wall Loudspeaker

The LCR8 simplifies the look of a multichannel theater system by doing the work of three front speakers. It delivers left, right, and center channel signals with the clean dialogue and distinct imaging you would expect from separate components.

www.revelspeakers.com

They show it with the grill off. I haven't tried to take it off yet. Seems like it's on there pretty good.

This thing looks like a sound bar but it's really a left, center, and right speaker all built into one long skinny cabinet. Each speaker has a 1" tweeter and two 3" mid-woofers on eiither side. This is great for me to try because I was thinking about building something like this. They also have these 3 speakers available as separates, so they could be each setup vertically. So far I'm using this thing crossed over to two cheap Sony 10" Subwoofers at 150 Hz. They image pretty well with my matrix array despite the twin woofer speakers each being set on their side. Sound quality seems pretty good, especially at lower volumes. It can get pretty loud and sound reasonably bold and rich. I'm enjoying it but not totally loving it. I should probably try it with a better amp. It's definitely sleek and convenient

I measured the center speaker and also a Sony SSCS5 with the same amplifier level setting - both at 1 meter on-axis. Green is the Sony. Output is very similar but the Sony goes a little lower. Distortion measures a bit higher pretty much across the board for the LCR8 except up above 5k. The Revel tweeter seems a little better.

When playing a sweep this thing sounds a bit like a didgeridoo down in the bass. It kind of looks like one too. Crossing it over at 150 helps.

 

[Tim Link]

After a couple days of listening to the Revel RCL 8 I found that to get pleasant sound out of it I needed to cross it over at 300Hz, and keep it forward of the TV a few feet. I also needed to be in a good mood. Placed directly under the screen as intended was not pleasant sounding to me. Today I plugged the Sony SSCS-5s back in, leaving everything the same in terms of levels, bass EQ, and crossover settings. Even with the crossover at 300Hz, 12db/octave the Sonys add a lot more weight to the bottom end, integrating with the bass cabinets dramatically better, making the bass seem more dynamic and impactful. I'd swear I changed bass cabinets! It's weird because above 300Hz the SSCS5 and LCR8 measured similarly, yet perceptually the are drastically different. The Sonys are so much better its laughable, and they cost a lot less. They are relatively bulky though. That slim, low profile of the LCR8 is nice. If I learned something here it's that what's happening in the range around 300Hz and above has a huge effect on percieved bass quality. I had some pleasant moments with the LCR8 but overall it lacked any weight and sounded awkward integrating with the bass, even with the crossover all the way up to 300Hz.

 

[STC]

reducing stereo crosstalk that occurs from the sound of the speakers reaching both ears instead of just the intended ear.



I mean great work and all but.....but...but....

That is how music is mixed and recorded to begin with. They realize it will be heard that way, and it is mixed and panned and so on with that all taken into account on the recording end of things.

Polk made this somewhat famous in the 80s as the SDA series of speakers, but never explained WHY it was needed, other than making the sound Gimmicky.

For TRUE Binaural records, YES it works to a great degree, just like how headphones do also.
But REAL stereo recordings you are supposed to hear the crosstalk, and it is intentional.

Am I the only one thinking crosstalk cancellation is being very unfaithful to the intended sound>?

Crosstalk cancellation when done right outperforms stereo.

Headphone listening gives you more details and clarity with a wide stage because of complete IAC cancellation but suffers in the head stage due to the absence of pinnae role to externalization the sound.

 

[STC]

How far apart do you have your speakers with the Holography running? If it works like I think it does it seems you could have them a bit closer together than usual. I've used RACE software before and that allowed me to have the speakers very close together while still producing a very wide stereo effect.

Carver’s Holography is a one shot cancellation while RACE is recursive. One shot cancellation works well with speakers placed very close. All crosstalk cancellation supposed to benefit when placed together Ambiodipole configuration as human are poor to localize frontal sound while speakers placed around 30 degrees off axis is very sensitive as pinna is sentive to localize sound coming from there.

RACE concept is making the speakers totally invisible and to rely on ITD and ILD encoded in the stereo recording to produce the audio scene.

BACCH supposed to work with speakers at wider placement as it somehow supposed to suppress the pinna function of localization though I am not sure how that is possible.

 

[beagleman]

Crosstalk cancellation when done right outperforms stereo.

Headphone listening gives you more details and clarity with a wide stage because of complete IAC cancellation but suffers in the head stage due to the absence of pinnae role to externalization the sound.

assuming you are talking the Polk method.....

Not sure how it can. The recordings (MOST normal pop/rock/country etc) and intended TO have Crosstalk, so by eliminating it at the speaker/playback end you are effectively changing the way the sound is based on a misconception.

Sure it can sound wider and so on, do not disagree. But it is not playing it back with even close to fidelity to the original soundstage but merely enhancing or making it appear wider than was intended.

Again a true Binaural recording will benefit AND retain the sound of the soundstage but 99% of commercial recordings are just being un-necessarily modified by the Polk crosstalk cancellation.

While it works great for sure on certain types of recordings, Polk took a lot of liberty to try to make it seem that it works on ALL recordings...it does not.

 

[STC]

Sure it can sound wider and so on, do not disagree. But it is not playing it back with even close to fidelity to the original soundstage but merely enhancing or making it appear wider than was intended.

I think it was Stanley Lipshitz promulgated the idea that crosstalk in good. Crosstalk cancellation doesn’t increase the width it is not supposed to. The problem with crosstalk is that it cannot deliver ITD difference that exceeds the arrival the sound to the next ear. So with XTC, you hear what is buried by the crosstalk hence a wider stage but not always as most recording stage is somewhat stuck to 60 degrees or so.

You may get some benefit of 3dB boost due to crosstalk in low frequency but otherwise I don’t see how it can benefit. I think Miller who is the expert on this topic is in this group and he can provide far better explanation.

 

[Tim Link]

@STC I just went to your website and hearing you in the background in that Norah Jones song startled me!

@beagleman You bring up some valid points. The majority of audiophiles are not using any kind of crosstalk elimination. I think a lot of people are accustomed to crosstalk. It's like a signature hallmark of stereo. However, I do not think the mixing and mastering is optimized and tuned with it in mind. It's just a parasitic effect, kind of like stereoscopic systems that suffer a bit of cross bleed to the other eye. You see a bit of ghosting but it's not an intended part of the program material. It's just a side effect. It does effect our perception of the material though. Someone once said something like "the medium is the message."

The medium is the message - Wikipedia

en.wikipedia.org

So from that perspective I'm doing something to the message by altering the playback method. I find it to be something good.

I've been thinking about my three speaker arrangement, and I've come to see it as more of a comb filter reducing arrangement than a crosstalk eliminating setup. It's basically a mono speaker with some side speakers to pull the stereo width back out. I don't get really strong inter-aural differences like a recursive system can, so for the most part the sound stage is about the same width as it would be with a well set up normal 2 speaker listening triangle. The thing I really appreciate is the trading of the phantom center for a real center. I think this works better than most real centers because the side speakers are very near, so they have a similar sound character to the center speaker, and they are pulled well away from the side walls, reducing early side reflections. The stereo imaging is nice, but I think it's the tone that I like even more, even though I've been complaining about it having a different character than the normal 2 speaker setup. That's to be expected because the comb filtering is drastically reduced and the speakers are positioned very differently in the room.
My sister came over with her kids last weekend. My nephew commented on how impressive the surround sound was. I took that as a complement. The sound stage seems appropriately wide and deep to me, not over top. I don't think most people are used to hearing good stereo imaging.

My next big plan is to build a dedicated horn version of this setup, which will have super tweeters, midrange horns, and upper bass horns. This setup will have the tweeters about 6" apart, the mids about 1' apart, and the bass about 2' centers. My simulations suggest the stereo effect will be optimized over a wider range of listening distances by spacing the drivers apart proportionally to their frequency ranges. The horns will also reduce floor, ceiling, and side wall reflections. I probably won't be able to start cutting wood until next year, which gives me some time to think further about it.

In the meantime, I'm still intrigued with trying recursive elimination on the side speakers only. I need to figure out how to implement that. It's basically just a fast, equalized echo of the same thing in each side channel for my setup. It should add a few dB of interaural difference while having no effect on center panned images.

 

[Few]

My next big plan is to build a dedicated horn version of this setup, which will have super tweeters, midrange horns, and upper bass horns. This setup will have the tweeters about 6" apart, the mids about 1' apart, and the bass about 2' centers. My simulations suggest the stereo effect will be optimized over a wider range of listening distances by spacing the drivers apart proportionally to their frequency ranges. The horns will also reduce floor, ceiling, and side wall reflections. I probably won't be able to start cutting wood until next year, which gives me some time to think further about it.

In the meantime, I'm still intrigued with trying recursive elimination on the side speakers only. I need to figure out how to implement that. It's basically just a fast, equalized echo of the same thing in each side channel for my setup. It should add a few dB of interaural difference while having no effect on center panned images.

Thanks for documenting your adventure. I'm interested in your findings. I had a Carver C-9 sonic holography unit in my system back in the 80s, when they were still current. Very picky about positioning, but a thrill for an audio-youth trying to push the "stereo" limits.

If you have DIY inclinations, you might consider building a simplified form of re-entrant horn (like Danley's Synergy horns, but not full-range or designed for such high SPLs). It's a bummer that physics dictates that narrowing the directivity at the low end of the system's frequency range increases the horn size. That complicates the speaker spacing and makes the speakers more intrusive in the listening room. That said, if you like horns, and want to listen relatively close to the speakers, they're a great option because they approximate point sources.

Admittedly, if DIY is not your thing, then such a project is likely not the place to start... I've found them not crazy-hard to put together, but there are multiple compound angles to wrestle with. I've also relied on miniDSP crossovers, and that implies multiple amp channels. Making them work passively, so you could stick with two amplifier channels, would require some engineering chops.

In any case, thanks putting the basic idea on my radar. A linear array of three effectively point-source horns would likely be a lot of fun to listen to! I'll be pondering the possibilities while I should be working...

Few

 

[Tim Link]

Thanks for documenting your adventure. I'm interested in your findings. I had a Carver C-9 sonic holography unit in my system back in the 80s, when they were still current. Very picky about positioning, but a thrill for an audio-youth trying to push the "stereo" limits.

If you have DIY inclinations, you might consider building a simplified form of re-entrant horn (like Danley's Synergy horns, but not full-range or designed for such high SPLs). It's a bummer that physics dictates that narrowing the directivity at the low end of the system's frequency range increases the horn size. That complicates the speaker spacing and makes the speakers more intrusive in the listening room. That said, if you like horns, and want to listen relatively close to the speakers, they're a great option because they approximate point sources.

Admittedly, if DIY is not your thing, then such a project is likely not the place to start... I've found them not crazy-hard to put together, but there are multiple compound angles to wrestle with. I've also relied on miniDSP crossovers, and that implies multiple amp channels. Making them work passively, so you could stick with two amplifier channels, would require some engineering chops.

In any case, thanks putting the basic idea on my radar. A linear array of three effectively point-source horns would likely be a lot of fun to listen to! I'll be pondering the possibilities while I should be working...

Few

The re-entrant horns are very interesting to me. I've not had a chance to listen to those yet. Strange that there aren't any major speaker manufacturers offering something along those lines. I guess a co-axial tweeter is as close as they get, and it's cheaper and easier to manufacture. Seems like the Klipsch Jubilee could have gone that route but they went for that extended range compression driver instead. I have some Klipschorns, and a re-entrant top section could be an option. I'm not sure how important the point source coherency is to me. They've got that going for them, but also potentially excellent constant dispersion. I know constant directivity is important to me as well, but I'm not sure how perfect it needs to be before perceptual diminishing returns come in. I've read reviews of the re-entrant horns compared to a tweet, mid, bass traditional stack of horns, and some people still prefer the traditional setup. It may just be what they're used to. I've listened to some of the JBL 308 monitors and depending on the setting they have sounded anywhere from fantastic to pretty good but kind of odd. When they sounded odd to me I couldn't say it was wrong, just not what I was used to. They sounded fantastic in my friend's heavily treated studio, which supposedly shouldn't be taking advantage of their excellent off-axis response because he was broad-band absorbing the crap out of every surface in that room. I didn't expect that room to sound good but it sure did! The bass was phenomenal in there and it was all coming from just those 2 308s! Highs were as natural and nice as I could imagine.

This 3 speaker configuration I'm playing with seems to lend itself well to separate tweeters, midrange, and mid-bass drivers because they seem to be best split further apart as the frequency gets lower. That's based on wave simulations but I need to try it with separate drivers to see if it really matters. Maybe as a start I should just buy some tweeters and see if moving them closer together compared to the mids makes any appreciable improvement.

I've also realized that any ambiophonic plug-in applied to the left and right side channels should do the trick of increasing the crosstalk reduction. I don't have to build anything to try that. I just need a plug-in that will work with Audio-Hijack, or perhaps a stand alone app that I can run the sound through. I also need to make sure that the processing of the side channels doesn't get them out of time sync. with the center channel.

Thanks for commenting!

 

[tjcinnamon]

I feel like I've come across something really fantastic! It started out as an attempt to simply derive a center channel from 2 channel stereo. By accident it turned out to be an outstanding crosstalk elimination method - much better than I thought at first because I hadn't dialed it in all the way. Turns out this sounds freakin' beautiful when listening on-axis, and still retains good tonal quality when off axis or even listening from another room. A slight adjustment transformed it from merely interesting to stunning.

For a long time now I've been interested in reducing stereo crosstalk that occurs from the sound of the speakers reaching both ears instead of just the intended ear. The gold standard for me was the result from using a physical divider that went right up to my face. Sounded amazing but a really uncomfortable way to listen. Now I've managed to get stellar results with no divider wall required, and it can be done with 3 small speakers and a two channel amplifier, with some very simple conversion of the left and right channels by converting one channel to sum and the other to difference. I did this in the digital domain on my Mac mini using Audio Hijack, as shown below.
View attachment 243429

The really important tweak to this Audio Hijack arrangement was adding the balance box at the end, which now instead of making the sound shift left or right, makes it wider or narrower by changing the ratio of the side channels to the center channel. You could also do this with the balance control on your pre-amp if it has one. The -12 percent off the center channel did the magic, fixing the somewhat hollow tone that was occurring and just bringing everything to life.

You do need three identical small speakers. They need to be arranged all in a row close enough together so the tweeters are ear distance from one another to get optimal on-axis response. The speakers must be narrow enough to accommodate that.

The speakers are wired with the center speaker getting the summed mono signal - which is the amp's right channel in my arrangement, and then the two outside speakers get the amp's left channel. I have them wired in parallel, with the right side speaker wired up backwards. This gives a L+R signal to the center speaker, a L-R signal to the left speaker, and a R-L signal to the right speaker.
Below you can see my humble array of three Sony SS-CS5 speakers which are currently blowing my mind. This is a different take on the Polk SDA concept and I think it works better.
If you're at all interested in crosstalk elimination I highly recommend you give this arrangement a try. This produces a very pure, clean, detailed, non-gimmicky stereo sound with excellent tone and musicality. No heavy handed processing is involved. Just simple summing and difference signals.
View attachment 243430

Book marked this! I have the L800’s which are fantastic but (in my next home theater), I could set one of these up with some L100’s and a minidsp for a rear channel or so something similar with just the L-R and R-L in the back

 

[tjcinnamon]

I did buy those! Those were my first floor standing speakers. I bought them with my enlistment bonus while in the Navy.
They don't work quite the same way, but it's similar. I didn't find them as effective as what I've got now. As a matter of fact I never got them to do much of interest at all in terms of stereo effects so I always left the connector cord unplugged. Looking back on it I understand now that the setup has to be very accurate and I'm sure I never got them set up adequately aligned for the signals to arrive at the ears at the right time. They can't be towed in, and have to be very close to equal distant to each ear so the setup is critical and difficult. It's so much easier to get accuracy in a tight array directly in front of you than with a wide separation of two speakers.

I've duplicated the SDA arrangement with four speakers on many occasions, and it does work with them all right next to each other. I've never been happy with it because while it does create a wide sound stage it also create a busy sound. A center panned image with SDA is being reproduced in four speakers at once rather than just one speaker. There was no way I could ever get that to sound clean and natural enough to prefer it overall.
As for Polk, placing the drivers about a foot apart makes me wonder. This seems like it actually does require some toe-in to prevent the outside drivers signal arriving at the ear too late. I don't really know why they have them so far apart. I got much better results with them closer to 6.5" apart - center to center.
Thinking about it I've decided what I've made might not be so much crosstalk cancellation but rather crosstalk obfuscation. What happens with a normal setup is that you get crosstalk that would create a coherent backwards soundstage if you could hear it and not the original sound that hit your ears first. With my arrangement you still get the crosstalk and it's still playing the wrong channel in each ear. But, it's also playing that same channel in the correct ear but out of phase. So the initial signal has had all the out of phase stuff canceled and it is coherent, but the crosstalk that comes next has everything out of phase across the head, which means it has no real location. So, it doesn't compete. It just makes everything louder and comb filtered, but differently in each ear. The only coherent signal that hit the head was the initial signal. The crosstalk is all out of phase and non localizable. It has spaciousness but is nebulous, and it's only applied to things not panned center.

I have the L800’s and because I have them between an 83” TV, I need to toe them in. However, they are fantastic speakers and have excellent XTC. In my next theater, I’m thinking I’m going to run a Halfer config with rears or something similar using Polk L100’s. Possibly replicating your setup using using a MiniDSP.

 

[Tim Link]

I have the L800’s and because I have them between an 83” TV, I need to toe them in. However, they are fantastic speakers and have excellent XTC. In my next theater, I’m thinking I’m going to run a Halfer config with rears or something similar using Polk L100’s. Possibly replicating your setup using using a MiniDSP.

I'd be interested in hearing the latest iteration of Polk SDA, or even the older ones with my current ears.

 

[tjcinnamon]

I'd be interested in hearing the latest iteration of Polk SDA, or even the older ones with my current ears.

I have no frame of reference to the older ones but these are quite nice. If youre ever passing through southern Wisconsin and can spare an hour or two. Hit me up

 

[Tim Link]

It's been almost a year since I started playing with this 3 speaker technique. Tonight I finally got a single baffle arrangement put together using a 2' x 4' x 3/4" plywood board, 3 Dayton waveguides with JBL 2426H drivers, and 3 Faital Pro 10" midranges. The crossover points are 200 and 2000 Hz, 24 dB / octave digital. Bass is still covered by the big corner horns with four 18" woofers in each corner.

I just got this put together tonight and hooked it up quickly with alligator clips. With a little EQ to get it close to the Harman curve I've been doing some initial listening tonight. This thing is already fantastic! Any weirdness I complained about with my earlier experiments is gone. The 10" Faital Pro drivers had good reviews so I took a chance. I was a little disappointed that it took some significant EQ to get the drivers really flat, but boy do they sound good! This thing can play so loud without any effort it's mind boggling. The open baffle arrangement makes for some really tight mid bass, and since they're only going down to 200Hz it's no problem. 100Hz is achievable. The imaging leaves me with no compaints. I don't know that I've ever heard a more natural and musical sounding system. I'm laughing at myself for questioning a 10" being able to cover the midrange up to 2K. I started with the crossover at 1.2K but 2k is definitely better. I haven't measured off axis yet but I'm guessing the off axis response is better at 2K. I believe JBL originally used this waveguide with a 10" crossed over at 2k. It's amazing how much better the deep bass seems to sound when the midbass and lower midrange are tight and punchy. I'm sure that un-braced, un-damped baffle board has to be making some noise. I can feel it vibrating. Whatever it's doing it's not particularly objectionable.

Next up is to incorporate this into a new TV stand

 

[Rip City Dave]

I love that you have the spirit and curiosity to build and experiment with this. The science is far beyond me, but it is nevertheless interesting.