Sherwood R-972 User Manual download pdf (Page 9)

R972 Trinnov Optimizer Application Notes Curt Hoyt trinnov.com

Ver 2.6.1 Page 9 3/12/12

Use suggestions in this document at your own risk. Always consult your Sherwood R972 Operating Instructions.

Stereo only, without the use of additional Subs. It could tighten up the bass and provide more extension. See note above- Full

Range Speakers w/ Internal Powered Subs.

Subwoofers

Trinnov measures and corrects for distance, level and frequency response for Subs. Angles are not required or measured. In

addition to frequency variations in the Sub, the room contributes dramatically to the response. The correction for Subs is based on

(7) independent, proprietary IIR filters that are computed specifically for your configuration. Typically boost is applied to fix

response errors in the Sub, and cut is applied to reduce the effect of room modes. The smaller the room, the more impact the room

will have on the Sub’s performance, as the longer wavelengths at lower frequencies exceed the room dimensions and so the waves

fold back and either cancel or magnify themselves. Picking the best place for the Sub to minimize the effects of the room modes will

mean that you’ll get all the more out of the correction. What you can do: Let’s say you have a few choices for placement. How to

pick? You can use the inverse positions to find the best spot. Place the Sub in the listening position, ideally at ear height. Set the

R972 to the pink noise for the Sub (Trinnov OFF, “test” on remote, when Sub noise is on, toggle 1dB to keep noise as long as you

need). While the noise is playing, go listen at each of the places that are acceptable for Sub placement. Maybe that means putting

your head in the corner… Listen to each. One will sound the smoothest, with the least amount of extremes. That is your implied

best location, and when you place the Sub there, that is what it will sound like from your seat. Then try calibrating with the new

placement.

Once you have your Sub configuration and are calibrated, typical users will want to run Sub at the corrected level for music and

somewhat louder for movies. If the crossover is below 100, moderately boosting the Sub should not add muddiness. Use your ears-

listen for distortion that can occur at louder levels, as one can over drive the Subs.

A way to accurately get Sub level where you want is to use the pink noise generator in the 972 with a radio shack meter

(on C weighting) measuring the change in level on the Sub. With the meter, you’ll know accurately what relative level

you have and can make incremental changes to listen to. I suggest trying 3dB at a time.

Multiple Subs

Consider using more then one Subwoofer. The multiple Subs will cancel out the room “modes,” or peaks and valleys in response.

Typical placement recommendation: for 2 Subs- placed mid-wall on opposite sides (side-side or front-back); for 4 Subs- all placed

mid-wall or if needed, corners. Connect all Subs to Sub out, and do your best to pre-match them for level. For smaller rooms, its

considered better to have more, smaller Subs then one bigger pricier one.

Trinnov finds the acoustical center, level, and response of multiple Subs and compensates for that. Multiple Subs are typically used

to smooth out room modes. If you use multiple Subs, start with equal level on each. Room mode nulls can result in very dramatic

level swings as high up as 200Hz. As a result, it can be very effective to counteract the modes from a main large Sub with a smaller

Sub of limited capacity ideally placed, set to a lower level. We use measurements to find this; you can do it by listening.

Speaker placement, using 2D or 3D Trinnov Remapping

You may include unusual placement for image enhancement, such as height, or wides. Technique is to place speakers

where you want more spatial definition, then calibrate. As we have more spatial acuity in the front, it makes a lot of

sense in most rooms that are not long and narrow to setup a typical 5.1 array, then use the extra two channels for

height or wides, or to “fix” a spatial problem. An example of this could be that there is a door, right where the left

channel should go. The solution may be to place a speaker on both sides of the door, then have Trinnov correct the

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Sherwood R-972 User Manual Page 9