Different crossover points?

[darien87]

Hey folks,

A recent phone call to Boston Acoustics has me wondering about something. Currently, I am running Boston Acoustics VR 2's as my fronts with a Cambridge Soundworks MC500 as my center channel. I was thinking that it might be better to go with a Boston center speaker to have all my fronts match. So I called up Boston and asked them what they recommended for me to use as a center and they told me the VRC.

I noticed that the frequency response of the VRC is 70hz - 20,000hz. However, I have my system crossed over at 60hz, due to the fact that my VR 2's play well down to 35hz or so. When I asked him about this discrepancy between my crossover point and the VRC's response, he told me to set my VR 2's to large and set my crossover at 80hz. Isn't this a bad thing?

So what I am wondering is; does anyone make a receiver that allows you to set different crossover points for different speakers, or is this pointless? Since my VR 2's can play down to about 30hz, I'd like to cross them over at 60hz and then cross over my center and surrounds at 80hz, since they cannot play as low. Does this make sense?

 

[MDS]

HK offers receivers with different xover points for each speaker and the recent Onkyo lineup does as well.

 

[j_garcia]

I believe *shudder* the Sony ES models can do this as well, but I've seen it on the H/Ks and it seems to work well. I setup my friend's ES and it had the ability to do this and he has towers for the mains and smaller bookshelf speakers for the rest as you do and setting the mains lower worked out pretty well.

 

[no. 5]

I believe that is a feature found in all of H/K’s receivers.

 

[darien87]

Thanks for the responses guys. Guess I may have to look at HK receivers.

 

[AVRat]

Denon's do also, but I"m not sure at what level the feature starts.

 

[jcPanny]

Crossover Test

Consider the following test with your current reciever. Play a stereo source in 2.1 with the crossover at 80 Hz and mains set to SMALL. Repeat with the crossover at 60 Hz.

If you have a descent sub, you probably wont hear any difference and you don't need the multiple crossover features. The Emotiva LMC-1 pre-pro also has the multiple crossover feature.

 

[darien87]

Denon's do also, but I"m not sure at what level the feature starts.

That's music to my ears, as I'm kinda partial to Denon, and I'm thinking of upgrading sometime soon anyway to take advantage of HDMI audio tracks.

 

[Nick250]

If you have a good sub, you may find that it does a better job of reproducing sound in the 40Hz to the 80Hz range that your speakers. Just because a speaker can in theory reproduce sound down to 35Hz does not mean it does a very good job of it.

Nick

 

[darien87]

If you have a good sub, you may find that it does a better job of reproducing sound in the 40Hz to the 80Hz range that your speakers. Just because a speaker can in theory reproduce sound down to 35Hz does not mean it does a very good job of it.

Nick

Thanks for the input Nick, but it's not theory. I tested my VR 2's with the Rives CD.

 

[chas_w]

Denon's do also, but I"m not sure at what level the feature starts.

I believe it is in the 2807 and above.

 

[chas_w]

The Outlaw 1070 also has this ability...Rotel receivers too I believe.

 

[Nick250]

Thanks for the input Nick, but it's not theory. I tested my VR 2's with the Rives CD.

No need to be snippy darien. Especially when you don't know what you are talking about. Unless you have been to Rives where they made a custom test disc calibrated specifically for your ears you are way off base. While calibration disks can be useful, not everyone's ears are built the same and they perceive sound differently, not to mention one's hearing changes over time and no setup disk can account. Why we audition speakers if we did not perceive sound differently.

Nick

 

[tubesaregood]

When I asked him about this discrepancy between my crossover point and the VRC's response, he told me to set my VR 2's to large and set my crossover at 80hz. Isn't this a bad thing?

Why is that suggestion so terrible? 80 Hz is a reasonable cutoff point for any subwoofer in my opinion. Just set the crossover at 80 Hz. Allowing your sub to produce another half octave isn't a big deal.

And I also agree with Nick250. Those speakers will go to 35 Hz. Great - why not let the sub do the hard work for the speakers? It will likely be able to get down there at higher SPL and SQL anyway.

 

[darien87]

No need to be snippy darien. Especially when you don't know what you are talking about. Unless you have been to Rives where they made a custom test disc calibrated specifically for your ears you are way off base. While calibration disks can be useful, not everyone's ears are built the same and they perceive sound differently, not to mention one's hearing changes over time and no setup disk can account. Why we audition speakers if we did not perceive sound differently.

Nick

How about you check yourself first Nick, before you go berating me? You said that just because a speaker can "theoretically" play down to 30hz because it is rated that way, doesn't necessarily mean it can or do it well; which I understand. We all know how data can be manipulated. I was merely trying to inform you that I had actually tested my speakers with the Rives disk and a Radio Shack SPL meter. How the hell am I way off base?!?!? Are you trying to tell me that using the Rives CD to generate a tone and measuring that tone with an SPL meter is pointless or inaccurate? I'm not going by what my ears tell me. I'm going by what the SPL meter said.

So if you took my statement to be defensive, I'm sorry, but you misunderstood my comment. I think you're the one that's way off base. So get off my back. You're the one that got all defensive for NO reason.

 

[darien87]

Why is that suggestion so terrible? 80 Hz is a reasonable cutoff point for any subwoofer in my opinion. Just set the crossover at 80 Hz. Allowing your sub to produce another half octave isn't a big deal.

And I also agree with Nick250. Those speakers will go to 35 Hz. Great - why not let the sub do the hard work for the speakers? It will likely be able to get down there at higher SPL and SQL anyway.

Hey Tubes,
I'm not questioning the 80hz crossover point. What I'm questioning is the suggestion too set my speakers to "Large".

 

[no. 5]

I'm not questioning the 80hz crossover point. What I'm questioning is the suggestion too set my speakers to "Large".

And rightly so, if the speakers only go down to 35Hz, any sound below that is going to be progressively quieter to the point that some frequencies would be lost altogether.
And there are other problems that can arise without using bass management too.

 

[WmAx]

Ideally, you want to have a crossover to limit the bandwidth to the mains, if you have a subwoofer. It is never optimal to leave the mains running full range alongside a subwoofer. Due to the different frequency responses of the mains vs. the subwoofer, the differing phase response ( phase is directly inter-related to frequency response ) can in some cases be of significant rotation difference to cause cancellation across a narrow range of frequencies. Also, a subwoofer ( a good subwoofer) usually will have lower distortion when playing low frequency content vs. the average standard woofers found in mains. By limiting the bass response of the mains, you may lower distortion at moderate to high volume levels. However, a proper crossover is another matter. I find that an 8th order slope is generally ideal for integration in general for subwoofers to mains ( due to many different factors that I don't want to get into right now ), but generally, receivers will only have a 2nd or 4th order crossover rate available. Assuming your reciever has a 4th order crossover rate, I would suggest trying to use a crossover frequency of about 60-70Hz, setting the main speakers to 'small', so that the crossover also filters these at this frequency setting.

If you are going to buy new reciever/amplification gear, I would recommend a total re-think of the normal considerations, as I can recommend to you equipment that will provide for vastly more control over your speaker system and provide for greater versatility and improved integration. So let me know if that is the case.

-Chris

 

[darien87]

Ideally, you want to have a crossover to limit the bandwidth to the mains, if you have a subwoofer. It is never optimal to leave the mains running full range alongside a subwoofer. Due to the different frequency responses of the mains vs. the subwoofer, the differing phase response ( phase is directly inter-related to frequency response ) can in some cases be of significant rotation difference to cause cancellation across a narrow range of frequencies. Also, a subwoofer ( a good subwoofer) usually will have lower distortion when playing low frequency content vs. the average standard woofers found in mains. By limiting the bass response of the mains, you may lower distortion at moderate to high volume levels. However, a proper crossover is another matter. I find that an 8th order slope is generally ideal for integration in general for subwoofers to mains ( due to many different factors that I don't want to get into right now ), but generally, receivers will only have a 2nd or 4th order crossover rate available. Assuming your reciever has a 4th order crossover rate, I would suggest trying to use a crossover frequency of about 60-70Hz, setting the main speakers to 'small', so that the crossover also filters these at this frequency setting.

If you are going to buy new reciever/amplification gear, I would recommend a total re-think of the normal considerations, as I can recommend to you equipment that will provide for vastly more control over your speaker system and provide for greater versatility and improved integration. So let me know if that is the case.

-Chris

Thanks for the info WmAx. I don't know what type of crossover rate my Denon 2805 uses. Basically what brought this question up, was the fact that I have speakers with vastly different frequency responses. My fronts are rated to 35hz, the center to 55hz and the rears to 80hz. I believe that I have heard distortion come from my center channel on occasion. I think this might have to do with the fact that my receiver was crossing over all the speakers at 60hz, (I have since changed my crossover to 80hz).

I was thinking that perhaps the 60hz crossover point was too low for the center channel, causing it to distort with the lower frequencies. I'm not sure how the crossover point affects the rears, because I would assume that not much bass information is sent to the surrounds. But if it is, then the 60hz crossover point is definitely too low for my rears.

So, yes I would definitely appreciate any suggestions towards gear that would allow me to set different crossover points for each speaker. I am planning on getting a new receiver some time in the near future, since I want one that will allow me to take advantage of HDMI audio anyway. So a unit that has HDMI and separate crossover points would be ideal.

 

[WmAx]

So, yes I would definitely appreciate any suggestions towards gear that would allow me to set different crossover points for each speaker. I am planning on getting a new receiver some time in the near future, since I want one that will allow me to take advantage of HDMI audio anyway. So a unit that has HDMI and separate crossover points would be ideal.

Take receiver of your choice with the input/outputs that you want(HDMI, etc.) and use the pre-outs to feed a professional audio DSP crossover (such as Behringer DCX2496) and then feed the DCX outputs to outboard amplification. Behringer A500 is the most cost effective ( and versatile ) amplification of which I am aware in this case. Each DCX2496 has 3 inputs and 6 outputs(which can be configured in any way you desire). So you need two DCX2496 for a 5.1 surround sound system. Add another for 6.1 or 7.1. The DCX units can be daisy chained together so that one is the master controller, and you can also hook a PC to them for configuration using the provided freeware utility. The DCX units will allow nearly any rate/frequency/topology that you so desire, and in addition, can provide for corrective frequency response on every channel individually. Also, it has programmable dynamic limiters/compressors that can be used to protect speakers from transients.

-Chris