Does series affect downstream speakers?

[toddsdonald]

It's been a very long time since I was in the forum. I've got a home theater center channel question: Recently I replaced my vizio 5.1 soundbar setup for something better but on a budget: All used stuff from eBay for for a good price, Sony DH550, Energy Take Classic speakers and a couple of Energy connesuer subs. So far so good, sounds super nice compared to what I had.

The Take Classic comes with a fairly small center channel, (still sounded nice), but I wanted a bigger sounds stage, so I picked up another Take Classic center channel and two more satellites. I've got the two center channels and the two satellites mounted under the TV and hooked up in series/parallel since they're rates at 8 ohms each and the amp only handles 6 ohm load.

So here's my question: Does running complete speaker cabinets with the crossovers still in them, in series affect the sound? I thought I recall that running series through a crossover, (or even through a woofer coil), in turn changes the response of the next speaker in series, (sort of like a choke coil on a woofer). My concern is that while the first speaker in series receiving the positive feed may sound as intended, the second in series may be over filtered... Or does the positive/negative at the terminal point sort of negate that concern?

Thanks

[Paul O]

So here's my question: Does running complete speaker cabinets with the crossovers still in them, in series affect the sound?

Short answer is no. The only thing that is shared between the speakers is the voltage produced by the amp, everything inside the speaker cabinets operates as if it is all alone.

[wogg]

That's incorrect in your case. It sounds like you've mixed 2 different design speakers in series. They have very different impedance profiles, which will cause the voltage and therefore power and output share to be dependent on the frequency, drastically altering the response.

In series, the larger resistor gets the voltage and power, at resonance a speaker has a high impedance, as well as at crossover points etc. If that resonance frequency isn't in alignment, the resonance in one speaker will notch filter the other.

Only put the same design speakers in series. Even then they won't be perfectly split.

[wogg]

BTW... if you parallel the disparate speakers, then series matched sets of parallel speakers, you'll avoid the problems I've described.

A few percent of difference between the same design speaker isn't a huge problem. A 5% difference in resistance will be less than 0.5dB variation.

[toddsdonald]

Thanks everyone. I'm pretty sure they're all identical with the exception of the cabinets. Each of the 4 speakers is from the Energy Take 5 Classic setup. They're all 2 ways supposedly timber matched and share identical woofers and tweeters. The center channel design has a slightly larger cabinet with 2 front facing ports, (I'm assuming to make it sound a tad larger, or perhaps because it's meant to mount to the wall), and the front left right and satellites are all identically matched with a single rear facing port.

Essentially what I've got for the center channel ensemble, is two of the satellites/mains and two of the center channels. The center channel amp output has two parallel cables, each of which goes into the positive of each of the centers, then out from the negative on those in series to the positives on the satellite styles and finally returning home from those to the amp negative.

Everything's measured out ear height, works good and sounds good, just wanted to make sure I wasn't mudding up the center channel tonal quality. I'm pretty shocked at how nice they sound for being so small.

A picture is worth a thousand words... Basically what I've got, is what's shown below in the pic, except with an extra center channel speaker and two additional bookshelf style speakers... Plus two powered 8" subs. 10 speakers total.. Left front, center channel (4 speakers), right front, right rear, right left and the 2 front firing subs

[wogg]

...
Essentially what I've got for the center channel ensemble, is two of the satellites/mains and two of the center channels. The center channel amp output has two parallel cables, each of which goes into the positive of each of the centers, then out from the negative on those in series to the positives on the satellite styles and finally returning home from those to the amp negative...

This is a problem. Even if they're the same drivers you have 2 different box sizes and alignments, causing those low frequency resonances to be different and alter their frequency response when in series. The crossovers may be slightly different as well if they did it correctly, so there could be some effect up in the frequency range.

Can you series the 2 center cabinets, then series the 2 satellite cabinets and run those to your parallel cables?

[toddsdonald]

Hi Wogg, That's actually how I had them wired originally, but then changed it. The thought process being that the actual center channels would be more apt to reproduce their intended frequencies if running in what would be essentially parallel, (direct power to positive terminals from the amp), and then incorporating the other two end speakers to add the resistance needed to maintain nominal 8 ohms and 89 spl, (while creating a little more coverage for the front sound stage), without much concern if they were a bit more subdued because of being fed by the negative side of the centers if that makes sense.

In other words, I was thinking that the centers should in theory behave as designed if both were fed positive direct from amp, (plus it would eliminate any weirdness from left to right because now they're symmetrical regardless of the sound characteristics). I figured if anything, the smaller cabinets on the outsides are positioned vertically which is better for dispersion, although they might have a narrower frequency, (perhaps more like a mid range), because their power was coming after the center channels crossovers.

Not sure... I was tempted to bypass the crossovers but didn't want to chance smoking those little speakers. Right now it's sounding pretty good, just wondering if it could be better. Transitions from center to left and right sound almost transparent which is cool. It's pretty clear sounding from the center's, but there's that never ending battle of not enough center channel to run at a moderate volume without the sound effects from movies taking over the room when they kick in. TV shows are usually fine. Not sure why they record movies like that, it's annoying.

[wogg]

I'd switch them back myself. If you're using your AVR to compensate with a little mic measurement routine it probably won't sound much different but will be easier for the software to work it out. If not, it theoretically should be more accurate to the manufacture's intended response.

Here's a dirty little secret... you've essentially applied some unintentional EQ to your center speaker setup. You are allowed to like it I'm not allowed to say that, cause we're always supposed to be chasing flat accurate response. In reality we're a tiny niche of folks that really care about that.

[wogg]

Here's a quick demonstration of what happens. This is an Xsim of just a raw RS100-8 and a RS180-8 impedance profile. The frequency response doesn't matter for this exercise, this is just to show what happens to the individual driver outputs when used like this. The RS100 could represent a smaller speaker with a smaller cabinet and higher Fb, while the RS180 represents the larger speaker with a lower Fb.

Here's the "bad" example where the 180 and 100 are in series, then a second pair are in parallel to bring it back down to 8 ohm nominal.


Interestingly enough, the summed frequency response simulates to flat anyway, but look at the individual curves for S1 and S2. That's the effect of the disparate resonances, a good 6dB up and down where the impedances differ.


If you series the 2 RS100's and the 2 RS180's separately, then parallel together. The frequency response output from both individual drivers and the sum are all flat. They're both on top of each other since they're using the same default flat SPL in Xsim.



I'm most surprised that the simulated sum output is the same either way. Of course, that's ONLY if the speakers are in close proximity and can couple, like in your layout. In that case you may not hear a difference at all. The downside then becomes asking more from one speaker over the other, maybe they can handle it or maybe not. If the speakers are spaced out in the room or elsewhere you'll definitely hear the difference.

[Chris Roemer]

So, if (essentially) you've made a "giant" CC (using 4 nearly identical speakers spread L > to > R), theoretically you're introducing all kinds of "comb filtering" (phase) issues. If you played a 3k test tone (probably coming mostly from the tweeters) and traveled a mic across the seating position (from side-to-side) the FR would look like : /\/\/\/\/\/\/\/\/\/\/\/\/\/\/ (maybe not QUITE so many "teeth"), which is where the comb-filtering name originates.

Not really a good idea, but if YOU like it, that's half the battle.

[toddsdonald]

Wow, thank you so much for the valuable insight! Wogg, you called it 100% correct, I'm using the little mic that comes with the receiver and doing the auto calibration, then setting it to "studio", which is supposed to be flat eq (as opposed to "engineer", or "dynamic".

The 6 db flux is interesting, I'll try hooking them up the way you mentioned, (each matching pair in series, then both of those in parallel), to see how it sounds and if it makes any audible difference. Personally I like flat frequency for home theater. With big stereo I usually prefer to brighten it up and deepen the bass, but TV and Movies are already so heavily mixed it seems counterproductive to run AV anything but flat.

Chris, I've read about the comb filtering and some say it's noticeable, others that it's not... I made sure I spaced them so that hopefully it wouldn't be as bad, yet kept then close enough so that they still sound like one big center channel. Not sure if I pulled it off or not lol.

I considered going bigger on all the speakers, but I'd already started with the small ones and truth be told they're pretty neat looking and incredibly clear. I think so far, all in all, I've invested about $400 with cables, gang plates, speakers, receiver, 4k HDMI cord, etc. If I went bigger, (say a full set of energy cb10s and a cc10 center), I'd probably have twice as much invested with an unknown outcome - no doubt better, but I'd be surprised if it would be a dramatic difference for everyday listening. Turned it up for a bit this weekend and honestly even these little speakers over power the room pretty easy. Scared the heck out of my grandson, he ran out of the house. I'll run it like this for a bit and see what happens. If I get adventurous I may try wiring the 4 separate centers as if they're one speaker and just use one crossover... Or build a center box and use the guts from these for the build. Decisions, decisions.

[LOUT]

Chris, I've read about the comb filtering and some say it's noticeable, others that it's not... I made sure I spaced them so that hopefully it wouldn't be as bad, yet kept then close enough so that they still sound like one big center channel. Not sure if I pulled it off or not lol.

The comb-filtering is a lot easier to notice if you play some pink-noise or white-noise and listen..then move your head around a little. This will make a noticeable moving phasing/filtering sound as the comb-filtered frequencies move around depending on slight changes in your listening/ear position.

More importantly (unless I'm mistaken), I'm pretty sure the best amount of spacing is as-little-as-possible between all the tweeters (if you have to use multiple tweeters..which you are in this situation).
Otherwise, what kind of spacing are you using that you heard was maybe more ideal for these to avoid comb-filtering problems?...I'm honestly curious because I always thought the best spacing was none (or as little as possible, particularly for anything making higher-frequencies).

[toddsdonald]

The comb-filtering is a lot easier to notice if you play some pink-noise or white-noise and listen..then move your head around a little. This will make a noticeable moving phasing/filtering sound as the comb-filtered frequencies move around depending on slight changes in your listening/ear position.

More importantly (unless I'm mistaken), I'm pretty sure the best amount of spacing is as-little-as-possible between all the tweeters (if you have to use multiple tweeters..which you are in this situation).
Otherwise, what kind of spacing are you using that you heard was maybe more ideal for these to avoid comb-filtering problems?...I'm honestly curious because I always thought the best spacing was none (or as little as possible, particularly for anything making higher-frequencies).

I'll check it out to see if I can hear anything different weird. As for the spacing, you're 100% correct on tight spacing between the tweeter and woofer in a single cabinet, (hence the fancy frontal design on these little energy speakers). When running speakers together, as far as I recall though, if the tweeters are too close to one another it causes "lobing" I think it's called. Basically where the waves from one are interfering with each other, causing yucky dispersion pattern. That's why I spaced the cabinets out a tad, so they all have their own breathing room and hopefully aren't causing a bunch of wave cancellation and lobing. That's my hillbilly theory on it anyway. The tweeters are probably a foot away from one another. The woofers are a little less than that.

[LOUT]

Now you've made me extra curious whether or not some extra space between two or more tweeters playing the same signal makes lobing better or worse.

I think (but could easily be wrong about some or all of this) lobing is a phase problem (specifically one at the crossover) where the change in timing/Zaxis between woofers causes the ideally flat area at the crossover point to dip as the signal goes out of phase from the timing/Zaxis of the speakers moving out of ideal...usually because of the listener moving while the speakers mostly hold still because they're not haunted or anything. And the larger spacing between drivers accentuates this changing of timing/Zaxis between the speakers when the listener moves, making smaller movements from the listener create more noticeable changing away from the speaker's ideal timing/Zaxis.
I could be mistaken...or lobing might be something else instead. Looking forward to some learning soon. :D

[toddsdonald]

A couple developments for those following this... So, I moved the right and left speakers to the recommended distance based on listening position, (8 feet apart and sitting 12 feet back). That made a world of difference and even though I didn't think it could sound better, it does.

The other thing I did was ordered up a pair of energy cb-10 speakers and an energy cc-10 center channel, to see how that sounds if I swap out the existing 6 separate Energy Take Classic speakers for the bigger connesuer line... Plus I've already got the two energy esw c8 connesuer subs. I'm not sure what to expect, if it'll sound better than what I've got or not, but it definitely would take care of having to run the 4 take classic speakers as one giant center channel and not have to wonder if all that series and parallel wiring is causing any issue, as well as the 4 woofers and tweeters possibly causing whatever weirdness might come from that.

Any thoughts? Stay tuned, I'll let you know how it goes. If the bigger left right center sounds better, I might move the take classics from the front and use a couple for high mounted Atmos or 7 channel rears... Not sure yet.

[toddsdonald]

Swapped out the Energy Take Classic setup for a matched set of Energy CB-10 bookshelf speakers on stands with an Energy CC-10 center channel speaker. Everything is working well and sounds nice.

As for the topic of this post and the resolution: The single center channel speaker is definitely cleaner sounding than the array of 4 separate Take Classic speakers. The entire 5.2 system comprised of the C10 speakers, matched to my dual Energy CSW C8 subwoofers is certainly more than this little room can handle. Usually the loudest we'll go is about 50% on the receiver volume knob which is pretty crazy loud with chest pounding bass and the special effects can get overwhelming, but with the right movies is quite captivating, very movie theater like in sound quality and presence. I'm not into the action films and all the make believe sounds, so my preferences are more towards dialogue or song with ambient surround effects, but Superman Man of Steel was amazing. Television style shows like Netflix Blacklist are super clean and all that work the engineers do behind the scenes plays out perfectly in the living room.

I'm only running a Sony DH550 which is a budget conscious receiver. I did get the Sony 800 Blu Ray player which is super nice. Audio settings were done automatically with the little microphone and speakers set to small, transferring LFE to the subs. It's set to Full Flat and Studio settings, which aside from "Pure Direct" is as flat as it gets, but perfectly suited to the Energy speakers as that's where they shine.

The Energy speakers are extremely responsive and clear. They can go from extreme loud with all the effects to dead silent and into dialogue or background music effortlessly.

Overall impressions comparing the Energy Take Classic vs Energy CC-10 CB-10 arrangement is bittersweet. Personally I preferred the Take Classic sound quality which was nothing short of amazing for their size and nearly transparent in a spooky way with ambient sounds, background music, and the way they pulled off object and dialogue placement with as much pinpoint accuracy as a 5 channel is capable of I would imagine. I really liked the way music playback was also, whether it was in a movie or on Pandora, it was hard to describe, just so clear and enjoyable with the most subtle details coming out with a presence that made us feel like we were there with the performers. The larger and more sensitive C10 setup is very good as well, but really doesn't start getting impressive until the volume goes up. At anything less than about 30 on the volume knob, the dialogue from the center is super clean and intelligible, but any spaciousness is lacking. Over that volume, especially half way or more, well in that case, there's really not much comparison. The Energy Take Classic speakers won't disappoint, but due to their size are easily surpassed by the bigger Energy 10 Connesuer speakers which come into their own when the power is delivered, but I'd say better suited to either a much larger room, or perhaps one that has a lot of carpet, furniture and so on. They'll easily overcome any weaknesses a room may present.