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Discussion Starter · #1 ·
I have a quick question before I order my surround speakers and was hoping you guys could help me decide.


I have a Yamaha RX-V673 receiver, an Outlaw LFM-1 EX Subwoofer, and Martin Logan Motion 20 towers. I'm considering either the Motion 2 or Motion 4 to use as surround and front presence speakers.


Link to the specs: http://www.martinlogan.com/motionSeries/specs.php


My concern is that my receiver requires that all speakers have the same crossover point. The Motion 4's frequency response is +-3 at 70Hz, and the Motion 2's frequency response is +-3 at 110Hz. I don't want to go above 80Hz for the crossover setting because the next option on my receiver is 100Hz and the sub is locatable when it's set that high. If the surrounds weren't limited, I'd honestly be thrilled at 60Hz because the towers sound wonderful on their own down that low.


My question is: Will I be missing out on surround effects if I set an 80Hz crossover and go with the Motion 2's due to the gap from 80Hz - 110Hz? I don't know how much low frequency actually goes to these speakers. The price is what's drawing me to the Motion 2's, as I've been finding deals for about half the price of the 4's, but I'd rather spend the extra money if it'll make a difference.


Thanks in advance for any suggestions!
 

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I think you will get the best performance from your system if you run the front main speakers full-range and do not limit their performance in any way.


Their natural low-frequency rolloff makes them very insensitive at the lowest frequencies, so there is no reason not to.


A center speaker has no bass function whatsoever, IMO, so I recommend setting them to operate only above 120 Hz.


Surround speakers also need produce no bass; I usually set them to operate from 80 hz up.


The subwoofer's low-pass filter should be set to approximately the low-frequency limit of your main front speakers; 50 Hz or 60 Hz, or whatever it is.


If your receiver will only allow one frequency setting, that kind of sucks.


In that case I would set it to 60 Hz for all and let it go at that. Any speakers that don't go down that low just won't go down that low because they can't; no problem.
 

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Quote:
Originally Posted by commsysman  /t/1523290/question-on-surround-spe...-frequency-response-needs-to-be#post_24504335


1.  I think you will get the best performance from your system if you run the front main speakers full-range and do not limit their performance in any way. Their natural low-frequency rolloff makes them very insensitive at the lowest frequencies, so there is no reason not to.


2.  A center speaker has no bass function whatsoever,........................................

     Surround speakers also need produce no bass;..............................................


3.  The subwoofer's low-pass filter should be set to approximately the low-frequency limit of your main front speakers; 50 Hz or 60 Hz, or whatever it is.


4.  If your receiver will only allow one frequency setting, that kind of sucks.


 
1.  I agree with this statement as it will allow the OP to set the bass-management to suit the center/surrounds.

2.  Nonsense.  The only reason you can get away with small centers and surrounds is bass management and that should be set properly.

3.  Nonsense.  The subwoofer's LP filter should be set at 120Hz since it affects only LFE and has nothing to with the bass management under discussion here.

4.  Yup.
 

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Discussion Starter · #4 ·
Thank you for the replies. I should have clarified about the front channels; I do have them set as full range. The yamaha has a feature called extra bass, where the fronts run full range. Then, from my understanding, everything below the crossover point that is set on the receiver is also sent to the subwoofer. So, if set at 60hz, the fronts play full range and the sub also plays 60hz and lower. The crossover on the sub itself is turned off via a switch on the sub.


With a setting of 80hz, I'd be within the center channel's abilities (motion 30), but wouldn't I be missing everything from 80-110hz on the front presence and surround channels if I went with the motion 2's? I'm concerned that I'll be missing surround effects, but I don't know if my concern is valid.


One other question that the reply raised for me... Should I set the sub's crossover? I have it turned off since I thought the receiver was controlling everything.


Thanks again for the help.
 

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Quote:
Originally Posted by esby80  /t/1523290/question-on-surround-spe...-frequency-response-needs-to-be#post_24505396


Thank you for the replies. I should have clarified about the front channels; I do have them set as full range. The yamaha has a feature called extra bass, where the fronts run full range. Then, from my understanding, everything below the crossover point that is set on the receiver is also sent to the subwoofer. So, if set at 60hz, the fronts play full range and the sub also plays 60hz and lower. The crossover on the sub itself is turned off via a switch on the sub.


With a setting of 80hz, I'd be within the center channel's abilities (motion 30), but wouldn't I be missing everything from 80-110hz on the front presence and surround channels if I went with the motion 2's? I'm concerned that I'll be missing surround effects, but I don't know if my concern is valid.


One other question that the reply raised for me... Should I set the sub's crossover? I have it turned off since I thought the receiver was controlling everything.


Thanks again for the help.
1.  Yes, turn off or bypass the crossover on the subwoofer, itself.

2.  Make sure the LFE lowpass filter on the receiver should be set to 120Hz.  This will affect only the LFE and not the redirected bass.
 

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Since you are asking before ordering the surround speakers, I recommend that you never, ever buy any speaker that cannot go deep enough for an 80 Hz crossover.  If you do, even if you replaced your receiver with something that would let you set the crossovers differently for each speaker, you would still need to set those higher than is good, or you will have a dip in your frequency response where they are not reproducing everything very well above the crossover point.

 

So do not buy the Motion 2 speakers.  The Motion 4 speakers are cutting it pretty close for the frequency response, and even they might not go low enough for an 80 Hz crossover to work really well.  The Motion 15 would be a better choice.

 

The other thing is, you absolutely should not be running your front speakers full range.  They cannot reproduce the deep bass that your subwoofer can, and if you make them try, they will distort more than if you filter out the really deep bass from them, that they cannot adequately reproduce anyway.  Set them to small and use a crossover of 80 Hz (since you are planning on buying other speakers that must have it that high; otherwise, 60 Hz might be okay).

 

And do not set the receiver for extra bass.  This will be bad for two reasons.  First, you will be getting extra distortion (see previous paragraph), and second, you will double up the upper bass (the part that both the subwoofer and the main speakers reproduce).  This will really screw up your frequency response.  Manufacturers put this on receivers because some people like bloated bass and do not care about accurately reproducing anything.

 

And bypass the subwoofer's crossover.  Just use the crossover in the receiver.
 
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Discussion Starter · #7 ·
Thanks for the help. I ended up going with the Motion 4's instead of the 2's. I appreciate it!
 
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