Model 7 XTRM Subwoofer Design Change?

[Delkat]

I was wondering if something changed in the new XTRM when they changed to the side firing woofer configuration; are the subs rolling off at 200hz like the Kentos?  I know on the Kentos using the M5-HPAs, the filters are set for 200hz.  I’m wondering why the side firing setup goes to 200hz instead of 100 (assuming they do) and how the M7-HPAs work now given they have a built in 100hz high pass filter. 
 

Thanks

[Richard Vandersteen]

Yes, the high pass is still 100Hz, but the room EQ is effective up to 200Hz.  This is why the KENTO disc is used for setting up the XTRM version.  RV

[Delkat]

Is there a reason the side firing can be controlled up to 200hz compared with the downward firing being limited to 100hz?  Is it because the downward was slot tuned for a certain frequency?

 

Thanks

[Richard Vandersteen]

33 minutes ago, Delkat said:

Is there a reason the side firing can be controlled up to 200hz compared with the downward firing being limited to 100hz?  Is it because the downward was slot tuned for a certain frequency?

 

Thanks

Delkat it was down firing, but we noticed less cabinet movement when we designed the KENTO .  Side CounterForce sub-woofers were necessary because the front baffle is too narrow for a driver large enough to go down to 100Hz so we moved it up to 200Hz.  Octave energy distributuion is better at 100Hz if the mid-bass driver can handle the power so we kept it at 100Hz on the flagship XTRM.  Again, the KENTO proved to have better room flexibility with adjustments up to 200Hz so we kept that.  It is not very often in my 45+ years where technology trickles up from a junior design, but it happens.  RV

[Delkat]

Thanks Richard.  I think I follow what you are saying. The smaller 6.5” mid-bass on the Kento couldn’t go down to 100 so you limited to 200 and had the side firing subs reach up to 200. On the XTRM, the 7” carbon/balsa driver is capable of handling the 100hz crossover so you stuck with this since it allows for better bass integration but you kept the adjustment on the sub up to 200 for better room integration. Does this mean the bass adjustments impact the mid-woofer also or just the amplified sub drivers?  I assume just the subs as maybe the mid-bass driver doesn’t create a lot of energy below 200hz?
 

I know very little about crossover design but am wondering how the mid-bass network works using the HP amps (or HP filters on conventional amps). Do you effectively use a low pass network to feed the mid-bass since the lower frequencies are being filtered upstream in the amp or do you still have a band pass filter to filter low and high?
 

On the XTRM the crossovers are spec’d at 100, 600 and 5K.  Does this mean you have the low pass (or band pass)  for the mid-bass at 3db down at 100 and 600 and then another band pass for the midrange at 3db down at 600 and 5K and finally a high pass at 3db down at 5K feeding the tweeter?

My Kentos have 200, 900 and 5K so the same midrange driver is covering a bit less range here but the (different) mid-bass is covering slightly more. 
 

Sorry for peppering you with questions. I’m just trying to get a little better understanding of how these things make such glorious sounds. 
 

Thanks

Todd

[Richard Vandersteen]

10 hours ago, Delkat said:

Thanks Richard.  I think I follow what you are saying. The smaller 6.5” mid-bass on the Kento couldn’t go down to 100 so you limited to 200 and had the side firing subs reach up to 200. On the XTRM, the 7” carbon/balsa driver is capable of handling the 100hz crossover so you stuck with this since it allows for better bass integration but you kept the adjustment on the sub up to 200 for better room integration. Does this mean the bass adjustments impact the mid-woofer also or just the amplified sub drivers?  I assume just the subs as maybe the mid-bass driver doesn’t create a lot of energy below 200hz?
 

I know very little about crossover design but am wondering how the mid-bass network works using the HP amps (or HP filters on conventional amps). Do you effectively use a low pass network to feed the mid-bass since the lower frequencies are being filtered upstream in the amp or do you still have a band pass filter to filter low and high?
 

On the XTRM the crossovers are spec’d at 100, 600 and 5K.  Does this mean you have the low pass (or band pass)  for the mid-bass at 3db down at 100 and 600 and then another band pass for the midrange at 3db down at 600 and 5K and finally a high pass at 3db down at 5K feeding the tweeter?

My Kentos have 200, 900 and 5K so the same midrange driver is covering a bit less range here but the (different) mid-bass is covering slightly more. 
 

Sorry for peppering you with questions. I’m just trying to get a little better understanding of how these things make such glorious sounds. 
 

Thanks

Todd

Todd, this would be a textbook if I answered it.  Call me at Vandersteen Audio 559-582-0324 anytime.  RV