TC Sounds VMP 18 User Manual

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VMP 18”

(Specifications Manual)

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VMP 18” variable mass passive-radiator

Fix and Variable Parameters

Parameter

15" VMP

Description

Qms 7 Mechanical Q

Cms

um/N, compliance

Dia

390

m meters, effective

Mms (Range)

690 – 2460

grams, effective mass

Fs (Range)

22 – 11.9

Hertz, Free Air Resonance

Empty

Nut

Mass (washers)

Resonance Frequency

Directions for Use

VMP’s are designed to supplement ports in bass-reflex systems. The TC Sounds VMP can be tuned lower by adding mass washers or higher by removing them from the adaptor under the cone. Adding additional VMP’s is equivalent to

increasing the port diameter in a ported system, and adding mass to a VMP is equivalent to increasing a port’s length.

Adding a second VMP to the system effectively raises the net tuning and additional mass must be added to both

VMP’s to maintain the same system tuning frequency as opposed to using just one VMP. Additional VMP’s increases

the resonator’s headroom and allows the subwoofer to push more air before compression. Ideally two same-sized

VMP’s should be used with one active driver, but TC VMP’s can be utilized on a 1:1 ratio in small box systems with

good results. If only one VMP is used, the subwoofer may be subject to shaking due to mass imbalance. This does not have any sonic problems, but fastening the enclosure may be necessary. Two opposing VMP’s will mass-cancel and eliminate shaking.

The above graph shows the free-air resonances of a VMP as additional mass-washers are added. For modeling a passive radiator system with a VMP, use any Fs number from the graph you like in addition to the fixed Cms, Qms and Cone Diameter above. Note that during the first few uses, the VMP will break in and the compliance will increase therefore lowering the effective Fs.

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Installation Dimensions

Aprox. Nut Mass: 205g Aprox. Washer Mass: 92g

Do not load more than 2.5kg of mass onto the VMP. For additional assistance visit www.tcsounds.com

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Warranty Includes:

 All manufacture defects  All obvious cosmetics  Improperly glued surrounds, suspensions, formers or misaligned coils  Detached or unglued surrounds  Broken cones from any forces from the driver itself not related to the impact of bottoming

out the voice coil

 Voice coils that collide with the gap or t-yoke under normal conditions where no preexisting

abuse has occurred

 Alignment of the voice coil or top assemblies/motors which don't fit each other  Motor glues

Not Covered By Warranty:

 Misuse or over excursion  Thermal abuse to the voice coil or glues around the voice coil  Thermal abuse to the lead wires on the spiders  Mechanical damage due to over excursion or excessive acceleration  Dents in the cone from bottoming out the driver or inadvertent force  Spider sag due to gravity in a down or up firing position for long periods of time  Damage due to moisture  Shipping damages  Cosmetic damage  Consequential damage on other components

For technical or service support please visit www.tcsounds.com or send us an email at [email protected]. Proof of purchase will be required for return authorization. If your driver

has a detachable top assembly and damage is not covered by warranty, a new replacement top assembly can be purchased from any TC Sounds authorized dealer or from TC Sounds directly.

Phone Numbers Business phone: (619) 955-5646

Address

4168 Poplar Street, Suite F San Diego, CA 92105