Quick question re new sub x-over

Hi, I've just installed 2 brand new (very powerful) subs into my HT... The frequency is from 29/150 and have a 320w amp per sub... They are connected to my denon 4311ci (xt32-subEQ etc)... After calibration my AVR set the xover to of all my speakers to 40hz (except my centre which is at 110)... My question, is as my speakers are technically only rated to 75hz (not 40) and my subs are reference subs, would I be better raising the xover from 40 to 80 or even 110/120 and sending those frequencys to my wonderful new subs which are currently lacking content. They can handle bass better, have enough filters, and we're bought to help produce a nicer sound all round... By raising the xover from 40hz to 80/110/120 etc all round (or to match my centre) and send all that content to my wonderful new subs which can definetly handle bass better than my speakers, is there any negative reason that I should NOT do this? ... Will removing to much bass from the other speakers cause a issue.... My subs are up front directly next to the left and right speakers respectively... Any advice is welcome.... Thanks in advance. .... Ps... I noticed that audyssey is setting my subs overall db after calibration down to apx 54db should I be worries about this? At the initial set up it was spot on 75db as per subEQ results. After calibration it altered the volume to -8 and -7.5 on the subs but during measurements I noticed that gives a reduction down to apx 54db on my sol meter where as all other speakers read dead on 75db. Is this normal behaviour?
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7 Comments

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    Chris Kyriakakis

    With XT32 there is no need to raise the crossover frequency.  The filter resolution in the sub and speakers is the same and much higher than previous versions of MultEQ.  Proximity of speakers to walls can have a big effect on the low frequency extension so that's the reason for the 40 Hz.

    Audyssey is most certainly not setting your subs to 54 dB!  That's most likely due to an issue with the calibration of your SPL meter.  Are you using C-weighting, Slow?

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    Paddy

    Hi,

    Yea c weighting is used. It measures all other speakers accurately as being dead on 75db but when I switch to my subs it's 54db and they are whisper quiet... Bizarrely when I set up the subs the mic was fluctuation from 60db up to 80db and It was impossible to get it to sit at a static db. Could it be that this means when audyssey did the first reading it spiked to above 80db so it cut it?...

    The reason I was asking about raising the xover was I was listening to tron and noticed some serious distortion (bassey sound track) so I disabled the subs (powered off at the subs) and listened to the audio without the subs active...

    I noticed my bass was distorting as the speakers were trying to play down to 40hz ... but when I raised the xover to 80 they were no longer playing these frequencies and sounded much better (less distortion).... When I activated the subs, they had those sounds going to them, and as they are very good subs, handle is very easily...

    Is there any negatives in moving my xover up to either 80-90-100-110-120hz and allowing my subs to take care the lower frequencies considering that I paid £1000 for them (they cost more than my speakers combined) and they are most definetly up for the job?... My satellites are only 4" little drivers that are rated to 75hz and don't seem to function well in the low range...

    I'll try again with the spl meter but I have ran it 3 times and I wonder if this anomoly is due to the inability to get the subs db to sit still during the initial setup?... Hope you can help further.

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    Chris Kyriakakis

    Measuring the speakers is easy.  SPL meters have trouble with subwoofers.  But, what you are reading is too low.  The sub measurement in the beginning is a coarse setting that gets you close to 75 dB.  The only reason it's there is to make sure that your sub volume is not turned up too high so that the AVR runs out of range.  The precise setting is done later during the MultEQ measurements.  What level is it finding for your sub?

    You can move the crossover up with no issues.

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    Paddy

    Hi,

    My volume on the back of the subs are between volume 1 and 2 on a scale of 1 to 10..... My AVR has set my subs to -9.0 and -7.5 repeectuflly..... I set the subs close to 75db on set up (with the exception that leaving the sub emitting it's tone for long enough on set up would cause it to erratically jump from 60db up to 80db then to sit at 75db and then drop back down to 60db and up to 85db etc etc etc they were very erratic...... Since running audyssey my subs emit almost omaudio in 2 ch stereo as they are volume 1 (out of 10) and are set to -9 on the AVR meaning they literally give out little to no audio what so ever..... This is duel subs (Identicle) and they are up front beside the left and right speakers..... What about raising my xover is there any negative undertones in doing this? It had taken away the pressure of my little 4" drivers and allowed the massiv subs to deal with bass. It seems logical to do this considering they are designed for low frequencys? Thanks for the advice so far.

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    Paddy

    Sorry, my last comment about xover was meant to ask what you would recommend. Would you crosattempt at 80 or would you recommend matching all the speakers to the center channel xover of 110 (speakers were reported as (40/110/40/60). They are little 4" drivers. Thanks again.

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    Paddy

    Hi, sorry for the triple post :) as an additional point... I worked out that raiding the xover of the LR to 80/90//110 etc reduces the bass distortion from those speakers as thy essentially stop playing those frequencys which is great ... Some distortion is utile still at 80 but raising this to 90/100/110 reduces this even more.... So my question, as the covers are blending at different freq, would it be in my interest (if raising them) to raise them relatively.... For example, if moving the LR up by 40hz, to move all the others up by 40hz to keep a similar level of consistency with the blending/when they cross? ... This would essentially put them as 80/110/80/100 which keeps that uniformity that audyssey gave them.... (except I didn't raise the centre in that example) if I do this, I'll get 80/150/80/100 again which is all still within my subs range and removes some of my speaker distortion when my little 4" drivers try to play such low frequencys... What's your opinion on this, if ou were me, what would you do (no buying new speakers though) lol :)

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    Chris Kyriakakis

    I recommend setting the ones found at 40 Hz to 80 Hz and leaving the rest as found.  It's not necessary to match them to the center.

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