New Cirrus Triple-Xover a good thing? (1 Viewer)

[Will]

That's understandable since we have huge towers speakers and a mega watt amp to drive them but I don't think triple xovers are the answer. IMHO the ability to set different xovers for 2 and 5 channel playback would be more useful.

Hey Ron,
I really agree with you that separate xovers for 2 and 5 channel playback would be quite useful. I am not looking forward to re-adjusting the crossovers when moving between 2 and 5 channel playback. But in 5 channel playback, I still like being able to adjust my rears higher than my fronts. Naturally I'd like to have identical crossovers all around as you suggest. But I can't afford and don't have room for huge full range tower speakers, all around. So I have two full range towers in front and compromise as best I can on the rest, which is what the triple crossover would seem to allow.

 

[Ron Alcasid]

Naturally I'd like to have identical crossovers all around as you suggest. But I can't afford and don't have room for huge full range tower speakers, all around.

Will, sorry I wasn't clear. I am not advocating we need to use full range towers all around. I am just saying in a 5 channel setup they all need to sound the same or close to similar as possible. Having different xovers detracts from that.

 

[Mifr44]

"I am just saying in a 5 channel setup they all need to sound the same or close to similar as possible."

This is the reason why THX setups work so well, with timber-balanced speakers being a benefit.

Michael

 

[Will]

While I do agree that identical timber matched speakers all around is desirable, I've found that combining similar sounding speakers, rather than the identical "timber matched" speakers that some speaker manufacturers say is a must item that we HAVE to HAVE, often works surprising well. I wouldn't want to combine totally different sounding speakers however. But I think room effects in typical listening rooms, may often totally overwhelm timber effects issues within similar sounding speakers. Again, the speakers should be similar sounding. I'm just not sure it matters that much if the timber of the surrounds is identical to the timber of the mains when there's a glass window between them, and pictures on the walls, and doorways all around, etc.

 

[Brandon B]

Another factor is it is a given that your main 2 or 3 are the most important speakers for 2 ch or HT.

Consequently, on a limited budget that most everyone has (although limits vary), you will generally want to maximize the quality of your mains, especially if you use them alone for your 2 channel purposes.

Therefore, it is likely most systems that have anything like full range mains are going to have much more limited surrounds. And again, if your mains even approach your sub in bass capabilities, it may make sense to let them handle more of the bass in their channels than the surrounds can in theirs. It's sort of the "I don't want to waste my mains setting them to small" argument, except in this case I AM saying set them to small, just not as small as the surrounds.

I would also be curious what the engineers at Outlaw and Crystal would say about this, since according to those who say this is a bad idea, they squandered system processing resources at the expense of other features deemed universally desireable (delay).

BB

 

[MatthewJ S]

I would ,respectfully, disagree with the point that there may be room interaction reasons that would negate the benifit of timbre matching...we would NEVER argue that ,because of picture and window issues, we would use differant front left and right speakers, so I find it difficult, in this day of multi-channell/high resolution music, to understand why we wouldn't always want matched surrounds and center...AS much as I like experimenting with differant amps,I found that this is also true for mixing different types of amps into a system...we wouldn't use a Krell mono amp for our right speaker and a forte mono amp for our left speaker, would we?

Of course this is my opinion, I could be wrong, but most of the rebuttals I have received in regaurds to this opinion have been someones anecdotal arguement that they have done a fine job adjusting their speakers and amps to be "balanced" ...And to be fair, I have heard Great systems that weren't perfectly matched, but I always come away wondering what if he matched everything? Unfortunately NOT everyone has the ability (for financial and other reasons)to match their speakers/amps (sometimes my problem ,too!)

 

[BruceD]

Michael,

I would not want THX speakers at all because they are designed specifically to standards that severely limit their off-axis output. I just don't like the way they sound. They may provide good HT movie sound for some, but they are just not my cup of tea for quality music reproduction.

Mathew,

According to basic acoustic principles, the room is actually the biggest variable. The speaker placement within that room makes a bigger difference than just identical speakers all-around. Why do people spend so much time just locating a single pair of speakers for 2-channel music reproduction? Because location in the room makes a huge difference.

__________________________________________________ __

My experience with flexible xovers is that they provide a smoother overall soundscape (for all speakers) when dealing with the rolloff characteristics of each speaker. I'm not trying to say "use the most bass from each speaker", rather I'm trying to get the best transfer or hand-off of bass to the sub while taking into account the speaker's designed-in bass rolloff.

This is where I think the Triple-xover can provide an advantage for those of us without 5 identical speakers. How many of us have identical speakers all around? I'm sure it's not the majority.

 

[Ricky T]

What is the official definition of a triple x-over?

 

[BruceD]

Ricky,

Options for xovers in the Triple-xover:

40Hz, 60Hz, 80Hz, 100Hz, 120Hz, 150Hz

Now, apply any combination of the above xovers to the three classes of speakers:

1) Front Left and Right

2) Center Front

3) All Surounds

Which means you can have different xovers for each of the 3 classes, and automatically integrate the time alignment, example:

Mains xover @60Hz

Center xover @100Hz

Surrounds xover @80Hz

 

[Ricky T]

Is this what the Sony ES and B&K processors/receivers have?

Lexicon has 3 crossover points (40, 80, 120) that can be applied independently to:

Mains - I use 40hz or Large for NHT 3.3s

Center - I use 120hz per Lexicon recommendation for logic7

Rears (and choice of dipoles or direct) = I use 120hz for superzeros

Sides (and choice of dipoles or direct) - I use 80hz

Sub (low pass filter choices) - I use 120hz (rear redirection and maximum LFE high point)

I think the MC12 has more crossover choices (and other enhancements such as stereo side subs).

 

[BruceD]

I don't know about Sony, but B&K is a universal All-for-One xover

Adjustable 20-200 Hz High/Low Pass Crossover

6, 12 or 24 dB/Oct Low Pass Crossover Slope

6 or 12 dB/Oct High Pass Crossover Slope

 

[Steve Morgan]

BruceD and Ricky the Ref 30 is global and you are right on the HZ's.I have Mains that are rated 32hz +-3 db's and my Center and rears are rated to 40hz.+ - 3db's. I have them all crossed-over at 60hz.I am wondering if 65hz or 80hz would be a better blend.I have 2 subs that are in the process of getting equalized with the help of Wayne,Bruced, Sonnie and Rick.After reading Brians post of crossing over an Octave above lowest rated output of the speaker I think individual speaker crossover setting would be beneficial but with slopes involved wouldn't it be much harder to equalize for room anamolies?

 

[MatthewJ S]

Bruce ,I have spent many days and hours within setting up speakers for a specific listening space/room..but what I want to make clear is that I never considered using different mnfgr's front left and right speakers to "AID" in those set-ups...and if we wouldn't do that for 2 channel, why would we do that for multi-channel high-resolution music?...One, very impressive, multi-channel demo I heard in Vegas let you enjoy the orchestral recording from the conductors platform,where you could hear the delicate presence of individual instruments "etched in space" between the left surround and left front speakers(and so on around the soundfield) and the comments all around(amongst people in the industry) were that this is why you need timbre matched speakers...Once I have those matched speakers ,then the set-up begins!

 

[BruceD]

Mathew,

I wonder if you set-up speakers with the same care and attention you apply to comprehending this thread?

I never considered using different mnfgr's front left and right speakers to "AID" in those set-ups...

I never said anything remotely similiar to your quote above. In fact it's quite humorous you would even mention using different manufacturers for Left and Right main speakers.

What I suggested is that basic acoustic principles (physics), professional measurements tools (MLS software), and your ears can balance the speaker/room interface more accurately than just ears alone. This becomes even more important when you have different sized enclosures for main, center, and surround speakers (from the same series and the same manufacturer).

 

[MatthewJ S]

Sorry Bruce, I must have misunderstood ,I thought you were writing about using differant BRANDS(or differant series within a brand) of speakers for fronts vs. surrounds...that is what I feel is a little less than ideal...my apologies for mis-reading....

 

[Lewis Besze]

Well I think both Bruce and Matt is right.

I think that 5 matching speakers are a good starting point,and then you can worry about it's placement.

Regarding the subs crossover point.

I was referring the bass managment's low pass xover point not the built in one in the sub[if there is one].

Which means that since most processor's BM reroute the bass from any speakers set to small to the sub,then naturally it should be set with the same highest setting,that you select on any other channels,say 100hz same as the center,or surround,even though you mains are set to 40hz.

I think it's safe to say that the sub may "sound" differently with the center or surrounds in conjunction,then with the mains,if the crossovers are set differently,as oppose to set the same all around like you would with 5 indentical speakers.

 

[BruceD]

Steve,

To answer your question,

I think individual speaker crossover setting would be beneficial but with slopes involved wouldn't it be much harder to equalize for room anamolies?

Not necessarily. Here is a quick synopsis on my understanding of the slope issue.

Speakers have a natural rolloff (slope) as they approach their low frequency -3dB point. This slope is not the same for every speaker. In fact most sealed or acoustic suspsension speakers may have the desired -12dB slope, but many ported or passive radiator speakers may have -18dB, -24dB, or even -36dB slopes.

The objective is to combine the high-pass -12dB slope of a pre-pro's THX xover with the rolloff slope of the speaker and come up with a -24dB high-pass slope. This is easy to do with the sealed speaker, but not so easy withy any other type of speaker.

The whole reason for this is to match the pre-pro's -24dB slope THX low-pass xover for the sub with a combined (pre-pro+speaker) -24dB slope for the high-pass so they even out across the xover from sub to speakers.

This whole exercise is to try and keep the frequency at the xover point flat and not produce a peak or null at the xover frequency.

Being able to control the slope allows for a better match at the xover frequency.

Hope that helps.

 

[Craig_Kg]

Many of the arguements presented here talk of the 80Hz 24db/octave bass rollof frequency required by THX though the 12db/octave slope of the prepro/receiver combined with the 12db/octave rollof of the speaker.

Does all bass redirection occur at this rate? ie Is 12 db/octave the rate at which all prepros perform bass redirection no matter what the redirection frequency is? And is this for all brands? Besides the B&K listed above that is.

 

[BruceD]

Craig,

Some prepros like Theta CasaNova and CasaBlanca and B&K ref30 allow you to change the slope of high-pass and/or low-pass xovers.

The "THX standards" definition of a xover for bass management is a symmetrical -24dB slope for both the high-pass and low-pass parts of the xover.

The low-pass portion is electronically -24dB in the prepro, the high-pass is a combination of an electrical -12dB in the prepro plus an expected acoustical -12dB from the speaker's low frequency rolloff characteristics.

The major problem is that only THX certified speakers actually have a -12dB rolloff at 80Hz. Sealed speakers also have a -12dB rolloff, but typically at a lower frequency than 80Hz. Ported speakers are all over the map, but not even close to a -12dB rolloff.

The mismatch of the acoustical+electronic high-pass xover slope from non-THX speakers means the high-pass xover will not be symmetrically blended with the low-pass xover, i.e. frequency anomolies will exist at the xover frequency.

 

[Mal P]

I personally would not like to use different cross-overs for different channels. The reason is that it may cause a less-integrated soundstage. If you had, say, a plane that was moving from Left -> Centre -> Right, and the cross-over point for the L/R channels were different to the Centre channel, then either the L/R or Centre channel could be "heavier" in terms of bass presence. This is especially so, as a lot of people like to run their subwoofer slightly hotter during films, to add a bit more "oomph".

The effect is slightly similar, but nowhere near as bad (since bass is harder to define in terms of tone), as having different sounding speakers across the front soundstage.

I don't think that using different cross-overs is completely a bad thing, as the less integrated soundstage may be off-set by the feeling that more of a certain speakers ability to produce bass is being utilized. However, it seems similar to that psychological aspect which causes people dislike at setting their expensive and large speakers as "small".

Cheers,

Mal