Originally Posted by Lesmor
Thanks for the replyThis switch should be set to "No Lowpass" before running Audyssey, and it should not be changed for afterwards, or for measurements. You are using the crossovers in your receiver, (assuming speakers have crossovers set, which should be the 80 Hz THX setting for your speakers.) You don't want to cascade crossovers.
As stated in a few posts I have Audyssey OFF Dynamic EQ Off
I am aware that the LPF should be on bypass when using Audyssey and have stated what Ausyssey sets the LPF to which is 120hz
( Which I have reduced at the moment to 80hz at a previous respondents suggestion)
My reference to using the sub LPF setting of THX 80HZ 24db/OCT was only done when connecting the XTZ Room Analyser direct into the sub
Why are you connecting XTZ direct to the sub? There is no benefit to that that I can think of. Connect XTZ to your receiver. Use the front panel stereo inputs, (which on my Integra pre/pro is the "Aux1" input.) Then select the Aux1input and put the pre/pro in stereo mode. If you want to measure the sub in isolation, just unplug the speakers. Plugging XTZ directly into the sub could be the cause of your level problems. I don't know the output signal level of the XTZ soundcard, but if it's significantly less than the output of your receiver, the signal will be too low for proper measurement.
As far as I am aware Audyssey and speaker distances trims etc are irrelevant if it is switched off and I am measuring freq response
Not true. Switching off Audyssey ONLY shuts off the EQ. The levels and distances are still in play. (Connecting direct to the sub will bypass all of Audyssey settings, but, as I said above, that is not advisable.)
With respect I am measuring response not running Audyssey unless I am missing something
If you are looking to find the best placements pre-Audyssey, (which is a very important and useful thing to do), then plug XTZ into the receiver, unplug your speakers and shut off Audyssey EQ, (which will also shut off DSX and DEQ/DV.) The Audyssey-set Distance setting won't matter with speakers off, (the Distance setting is used to optimize the blend of speakers and subs around the crossover... with the speakers off, there is no "blend.") However, set up this way, you will still see the effects of the level settings, (which you want), as well as the effects of the crossover and the LPF of LFE, (which you also want.) Then move your subs around to evaluate as many placements as you have. Once you find the spots with the fewest nulls, leave the subs there. (Nulls are much less amenable to EQ than peaks. Peaks can be cut with EQ; nulls need boost and boost uses extra amplifier power and driver excursion. More importantly, nulls are cancellations and adding energy just causes more cancellation.)
Check your manual on this, but I believe this should be set on Anechoic. The THX setting is for situations where you don't have Bass Management in the receiver.
The Bass EQ switch has two settings, THX and Anechoic. The THX setting produces the flattest response and is recommended for most installations. The Anechoic setting produces a flat anechoic response, which results in an increase in level below 30Hz due to room gain. This increase is about 12 dB/octave. The Anechoic setting is provided for measurement purposes and for those who might want this sonic profile. However, this setting limits the subwoofer's output and dynamic range.
I suggest you measure your system with this setting both on and off to see it's effect. If the Anechoic setting provides flatter response with deeper extension, I would strongly consider using it.
I don't understand this. The switch has 2 settings, THX or Variable. Which do you have it set on? If it's set to Variable, how do you adjust the level? I don't see a variable level control. Since your receiver is THX certified, I would put this setting to THX, use the THX crossover in your receiver and the subwoofer trim controls in the receiver to control the levels.
It is set to variable and you can see the gain adjustment knob at the right
This knob has been set to give a reading of 75db on the ONKYO display prior to running Audyssey and as you rightly say once Audyssey has been run no settings should be changed
I can't find a copy of the manual for your subs online. Can you please check your manual to see how this setting works? It appears that the THX setting is linked to the dial on the right, not the Variable setting. Some clarification is needed.
It is the gain on the Subwoofer that should be set prior to running Audyssey not the trims as having the gain on THX the level will be too high and the receiver will not have enough trim to reduce it
Audyssey ignores all trim settings set before it runs. It measures the levels of the chirps and adjusts the trims according to the levels it measures in-room. Again, since your receiver is THX certified, it is designed for use with a THX sub set to the THX input level. It should be "in range" with this setting.
Also I have given the trim readings of -4.0 and -4.5 which are within tolerance
They may be within tolerance, but something is definitely still wrong with your calibration. I'm trying to help you find out what it is.
I found your manual online:
From your manual:
TESTING THE SUBWOOFER (THX MODE)
Once all of the interconnect cables are in place, you are just about ready to plug in the subwoofer.
Set the "LOW PASS FILTER" toggle switch to the "THX MODE" position. Set the "BASS LEVEL"
toggle switch to the "THX" position. Set the "BASS EQ" toggle switch to the "THX" position.
Set the "PHASE" switch to the "+" position. If your THX controller has a SUBWOOFER (OFF/ON)
switch on its front panel, rear panel, or remote control, set it to ON. (See the controller's manual).
Plug the subwoofer's AC cord in. The red LED on the back panel should illuminate.
Play some program material with good bass content through your system. Carefully advance the
system volume control. You should hear the subwoofer operate. If you think the subwoofer isn't
working, walk up to the speaker and listen to it from a distance of a foot or less.
If you confirm that it is not working, unplug the subwoofer and check all of your connections before
trying again. If you have a problem that you cannot solve, contact your dealer or the M&K factory.
When your system wiring is complete and the subwoofer is plugged into the wall, leave it plugged
in, even when the system is turned off. The normal mode of operation for the subwoofer is to remain
plugged in 24 hours a day. Among other things, this means that you don't have to walk over to the
subwoofer to turn it on every time you want to use the system.
DO NOT PLUG THE SUBWOOFER INTO A SWITCHED OUTLET ON ANOTHER COMPONENT. IT CAN DRAW UP
TO 600 WATTS FROM THE AC LINE. IT MUST BE PLUGGED INTO A SOLID AC LINE.
5. CALIBRATING THE SUBWOOFER (THX)
On the back panel of the subwoofer, four toggle switches allow you to select various modes of
operation. Three are described here. A description of the function of the fourth toggle switch can
be found in section 7, SATELLITE & SUBWOOFER PHASING TEST (page 12).
OPERATION OF THE "LOW PASS FILTER" SWITCH (THX)
When using the subwoofer with a THX controller, set this switch to the "THX MODE" position. When
using the subwoofer with a standard stereo system or a surround sound processor that is not THXcertified,
set this switch to either "80 Hz 24 dB/OCTAVE" or the "VARIABLE" (center) position.
The THX mode bypasses the internal crossover of the subwoofer.. The THX controller contains the
crossover and sets the rolloff point of the signal fed to the subwoofer to 80 Hz (with a Linkwitz-Riley
OPERATION OF THE "BASS LEVEL" SWITCH (THX)
When using the subwoofer with a THX controller, set this switch to the "THX" position. The
controller sets the output level of the subwoofer, so this switch disables the subwoofer's level control.
This position provides a sensitivity of 90 dB SPL for 100 mV input for one subwoofer in the system.
The "REFERENCE" level control mark is calibrated to the level set by the "THX" switch. If you set
the switch to "VARIABLE" and the level control to "REFERENCE," its output level is the same as when
you set the toggle switch to "THX." The +3 and +6 marks indicate the points where your subwoofer
is producing 3 dB and 6 dB more output, respectively, than the "REFERENCE" level.
OPERATION OF THE "BASS EQ" SWITCH (THX)
Set this switch to the "THX" position. The "THX" position gives you the flattest in-room frequency
response, with flat bass extension to frequencies well below 20 Hz. This position is the most accurate,
THX subwoofers page 7
and it gives you maximum output level, dynamic range, and headroom. In your listening room, the
"ANECHOIC" position will actually produce a rising output below about 30 Hz. Its response is not as
flat (accurate) as the "THX" position and it limits the subwoofer's maximum output and dynamic range.
For performance to THX specifications, this switch must be set to the "THX" position.
SETTING SUBWOOFER LEVEL (THX)
The proper method of setting the level of the subwoofer in THX mode is to use the low frequency
pink noise test signal generator built into the THX controller and a sound level meter (available from
Radio Shack). First set the master volume of the THX controller to the "0" or "REF" position. Then
set the Subwoofer Output control on the THX controller so that the output of the subwoofer causes
the sound level meter to read 75 dB (C scale, slow mode) when that test signal is playing. All channels
of the THX system should be calibrated to this 75 dB level when using the unit's internal test signal.
Special Note: When calibrating the subwoofer level (and only the subwoofer level), you will find
that the needle on your sound level meter will bounce plus or minus a couple of decibels when
measuring the test signal. To set subwoofer level, read the AVERAGE meter level, not the peak level.
Move around the room as you measure levels, so that your measurements account for the room
reinforcements and cancellations found at various room locations.
For details on setting levels with your THX controller, see the instructions provided with that unit.
Your receiver is a "THX Controller" so these instructions should be followed precisely. The section on setting the level will be performed by Audyssey when it sets the subwoofer trims. It will ping each sub separately, measure it for level and distance, then ping both subs together for their combined level. Once you've done that, you're subs should be at the same level as your speakers. Audyssey may not get the speaker crossovers exactly correct at 80 Hz. Go in and manually reset them to 80 Hz. You can then go back and shut Audyssey off, shut the speakers off and try various placements of the subs. All the important settings will be retained, but the EQ will be shut off, so you can see the subs' response in isolation, (without the speakers), and without any EQ. When you've found the optimal placements, re-connect the speakers and re-run Audyssey.