Center and Surrounds Crossover Suggestions...

[PearlcorderS701]

I have settled on a 60Hz crossover for my Polk RTi12 mains because they're so large as I would like to utilize some of their punch along with my sub, but I'm still getting stuck on what would sound best for my CSi30 center and the SpeakerCraft in-ceiling surrounds; right now, I'm keeping the center and surrounds on an 80Hz crossover, but since I do not know the model of in-celing SpeakerCraft speakers that are in my theater room's ceiling (the house had them pre-installed), I don't know what the "better" crossover would be for these.

I'm assuming 80Hz (as it's specified by THX) is okay for the Polk CSi30 center as that speaker can put out a good deal of punch for effects and such; but with the SpeakerCraft surrounds, the 80Hz setting seems to be a bit too low for these; unless my ears are tricking me, I believe I can sense some "crackly" characteristics coming from them (the system is calibrated and isn't distorting in any other way) which is leading me to think they're taking on too much sonic information. Should these in-ceiling surrounds be raised to a 100 or higher crossover? Is there a "set standard" for in-wall or in-ceiling speakers when it comes to crossover points?

 

[sholling]

Polk rates the CSi30 at 55hz to 26khz -3db. Based on that anywhere over 60hz should be fine but I'd be tempted start at 80hz and see how it sounds. Since I have no idea what the specs are on the SpeakerCrafts all I can tell you is I would go with just above the lower limit of of its rating or 80hz - whichever is higher.

 

[PearlcorderS701]

Polk rates the CSi30 at 55hz to 26khz -3db. Based on that anywhere over 60hz should be fine but I'd be tempted start at 80hz and see how it sounds. Since I have no idea what the specs are on the SpeakerCrafts all I can tell you is I would go with just above the lower limit of of its rating or 80hz - whichever is higher.

Thanks, Sholling, as always.

I do have the CSi30 at 80Hz, and haven't had any "problems" that I can sense or speak of; tactile effects seem accurate through this center at 80. Can you explain to me why you recommend the 80Hz setting based on Polk's ratings you quote above? Just trying to understand the science behind the suggestion...

As for the SpeakerCrafts, I don't know the specs either, but I was wondering if in-walls or in-ceilings have a certain "standard" in terms of what their crossovers should be -- if they should be higher than 80Hz, etc.

 

[AVRat]

If the SC's woofer is >5", an 80Hz xover should be just fine.

 

[sholling]

I do have the CSi30 at 80Hz, and haven't had any "problems" that I can sense or speak of; tactile effects seem accurate through this center at 80. Can you explain to me why you recommend the 80Hz setting based on Polk's ratings you quote above? Just trying to understand the science behind the suggestion...

Much of the "science" is based on an understanding of marketing types. If marketing materials spec a speaker at say 55-24khz -3db I'm going to assume that's under ideal conditions, in an ideal room, at ideal volumes, and with the audio engineer's tongue hanging from the left side of his mouth instead of the right, and want to try to back off at least 10hz from that lower limit. I'm also going to assume that they are using -3db instead of +/-3db for a reason, like perhaps a nasty bump someplace - probably near the upper or lower limit of the frequency response.

80hz is a nice round figure. Low enough that the transition from the speaker to the sub and back is pretty transparent (if the sub is setup properly) and high enough to take some load off the receiver and avoid the lower limits of the speaker. Taking some load off the receiver can be enough reason by itself. My new center is rated as close to dead flat to 40hz as anything you'll run into but I'm still crossing it over at 60hz just to take some load off the receiver and may eventually bump that to 80hz.

 

[PearlcorderS701]

If the SC's woofer is >5", an 80Hz xover should be just fine.

Thanks, 'Rat...

I am technically uncertain about the speakers' diameters and woofers, but would you guess to say that small in-ceiling or in-wall speakers can maybe better benefit from a higher crossover setting -- something like 100Hz or more?

 

[PearlcorderS701]

Much of the "science" is based on an understanding of marketing types. If marketing materials spec a speaker at say 55-24khz -3db I'm going to assume that's under ideal conditions, in an ideal room, at ideal volumes, and with the audio engineer's tongue hanging from the left side of his mouth instead of the right, and want to try to back off at least 10hz from that lower limit. I'm also going to assume that they are using -3db instead of +/-3db for a reason, like perhaps a nasty bump someplace - probably near the upper or lower limit of the frequency response.

80hz is a nice round figure. Low enough that the transition from the speaker to the sub and back is pretty transparent (if the sub is setup properly) and high enough to take some load off the receiver and avoid the lower limits of the speaker. Taking some load off the receiver can be enough reason by itself. My new center is rated as close to dead flat to 40hz as anything you'll run into but I'm still crossing it over at 60hz just to take some load off the receiver and may eventually bump that to 80hz.

My reasoning for the "80Hz across the board" perspective was also to take a big load off the receiver -- but with speakers as small as the SpeakerCraft in-ceiling models, I am wondering if too much crossover information is being fed to them at an 80 setting, and perhaps this should be 100Hz or higher...

So, would you say that, based on Polk's specs, my CSi30 center can remain comfortable at 80Hz?

 

[sholling]

My reasoning for the "80Hz across the board" perspective was also to take a big load off the receiver -- but with speakers as small as the SpeakerCraft in-ceiling models, I am wondering if too much crossover information is being fed to them at an 80 setting, and perhaps this should be 100Hz or higher...

So, would you say that, based on Polk's specs, my CSi30 center can remain comfortable at 80Hz?

Based on the center's specs 80hz is a great place to start and see how you like it. If it works for your ears then you have your answer. Hopefully your receiver allows multiple crossover points and then you could try the in-ceilings at 100hz. I would think your receiver's setup program would have a recommendation.

 

[PearlcorderS701]

Based on the center's specs 80hz is a great place to start and see how you like it. If it works for your ears then you have your answer. Hopefully your receiver allows multiple crossover points and then you could try the in-ceilings at 100hz. I would think your receiver's setup program would have a recommendation.

The receiver's setup program's "recommendation" wasn't much to take into consideration, as it placed nearly all speakers as "Full Range" which is clearly wrong. But from what I understand, this is typical of auto-setup routines...

 

[PENG]

I agree with the suggestions to set the csi30 to 80 hz maximum. For the ceiling speakers if you could hear any distortion from them try 100 or even 120 hz. 80 Hz is a good number for most people regardless as it helps avoid bass cancellations between the speakers and the subwoofers and you may end up getting less bass if you set your speakers to lower than 80 hz.

 

[PearlcorderS701]

I agree with the suggestions to set the csi30 to 80 hz maximum.

Thanks, PENG. I'm thinking just to leave the center at 80.

For the ceiling speakers if you could hear any distortion from them try 100 or even 120 hz. 80 Hz is a good number for most people regardless as it helps avoid bass cancellations between the speakers and the subwoofers and you may end up getting less bass if you set your speakers to lower than 80 hz.

I realize that I'd be getting less bass with a setting HIGHER than 80Hz from those ceiling speakers -- but what do you mean less bass if I set them LOWER than 80Hz? Less bass from the sub itself?

I'm looking to relieve the low-frequency load from the smallish ceiling speakers; wouldn't this mean going HIGHER than 80Hz?

 

[sholling]

I realize that I'd be getting less bass with a setting HIGHER than 80Hz from those ceiling speakers -- but what do you mean less bass if I set them LOWER than 80Hz? Less bass from the sub itself?

I think he's trying to tell you that if you set the crossover lower than the speakers can produce then you will be left with a hole between where the speakers leaves off and the subwoofer picks up the load.