ELAC Subwoofer Frequently Asked Questions by Andrew Jones

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This topic contains 3 replies, has 4 voices, and was last updated by  mrvenkat25 6 months, 3 weeks ago.

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  • #4434

    Chris Walker

    Q1. How do I connect the S10EQ or S12EQ to my 2-channel stereo system?

    A1. Firstly you will need an amplifier that has a spare set of line level outputs that are in parallel with the main outputs. Then you will need a stereo to mono converter to combine the two channels into mono to feed to the subwoofer. This is an example of one such device

    Q2. My receiver has two subwoofer outputs? How do I connect the subwoofer?

    A2. When a receiver has dual subwoofer outputs the two are typically duplicates of each other with a common internal connection. You are therefore free to choose whichever is most convenient. If they are independent, and you have only one subwoofer, then simply choose one of them and indicate in the receiver setup which one you have chosen to use.

    Q3. How do you control the S10EQ or S12EQ subwoofers? It looks like they do not have any controls.

    A3. All controls for the subwoofer that would normally be located on the back of the subwoofer have been replaced by a remote adjustment over Bluetooth, accessible from our Sub Control app running on an Andoid or iOS phone. This makes it much more convenient: the setup of the sub can be done in real time from your listening position, without constantly having to get up to adjust the controls on the back of a conventional subwoofer.

    Q4. Why does the S10EQ and S12EQ use a passive radiator instead of a port?

    A4. In low cost subwoofers, a vent is used to assist the bass out capability of the subwoofer. The vent is typically tuned to operate at the lowest frequency that the subwoofer is designed to operate at. At this frequency, the vent takes over the task of moving air to produce bass, and the driver itself does little of the work. The downside of this is that the air velocity can became very large, particularly with small diameter vents. At these high velocities the air becomes turbulent and you can hear this as “chuffing” noises. Although this can be helped by adding flares to both ends of the vent, it’s difficult to eliminate entirely. If the vent diameter is increased the airflow can be reduced, but the vent has to be made longer to keep the same tuning frequency. At some point, the vent becomes too large to fit into the box!
    The solution is to replace the vent with a passive radiator. This is a driver unit of the same size or larger than the main woofer, but it has had its motor structure removed. It becomes just a passive diaphragm driven by the air inside the cabinet. The mass is chosen to match the equivalent of the mass of air that was in the vent, but because of it’s large size the movement is much less than the air it replaces. As a result, there is no “chuffing” and it behaves much more linearly.

    Q5. How does the Auto EQ feature on the S10EQ and S12EQ subwoofer work?

    A5. The Auto EQ works in a way that is subtly different from conventional EQ methods. In those, a calibrated microphone is required, and the response measured at the listening location is adjusted to match some “ideal” response determined by the software engineer. This is not the response that was designed by the speaker engineer themselves! Ideally, when the subwoofer engineer designs the subwoofer they have an idea of what performance they want the speaker to achieve. The limitation is that the room will modify this, hence the need for EQ. But the ideal is that the EQ gives at the listening location the response desired by the speaker engineer. This is the approach utilized in ELACs’ process. It allows for a clever change in the requirement of the microphone. We no longer require a calibrated microphone. In fact we utilize the microphone built into the smartphone itself!

    The process is to hold the phone very close to the subwoofer, the so-called “nearfield”. At this location, the measured response is devoid of almost any influence from the room, and is measuring in fact the designed response of the subwoofer. Once this response is captured, the smartphone is relocated to the listening location and a second measurement made. Next a set of filters is adjusted automatically to make the response measured at the listening location match that made in the nearfield of the subwoofer. The actual performance of the microphone is now of no importance: it is the same for both measurements and we are simply adjusting to minimize the difference! The sound heard at the listening location is now the one that the designer wanted you to have. It’s a very cool technique.

    Q6. Is the microphone in my cell phone or tablet good enough for setting up the S10EQ or S12EQ?

    A6. The requirement for the microphone is simply that it has a response that has some capability down to 20Hz with useable signal to noise ratio. The exact response is of no importance since that function is eliminated form influencing our process. We have found that the majority of modern phones and tablets meet this requirement. For those few that do not, it is possible to purchase a simple low cost calibrated mic that plugs into the mic input of the phone or tablet to give better performance.

  • #7335


    In above Q5, AVR should be on and at what volume should the volume be set when using the sub control app on phone?

  • #7891


    WRT Question #1: My receiver does not have sub-out or LFE out connections. Each channel (right / left) has 2 female RCA outlet jacks. Sounds like I need an adapter to convert those 2 female RCA outlet jacks into 1?. or do I just work off of the signal from one channel?
    Thanks, Jon

  • #9243


    I have an Elac tower system with an active subwoofer. The subwoofer is on auto mode. When the amplifer (demon) is on standby mode, there is a slight thump like sound emanating from the subwoofer at infrequent intervals. The thump sound is mild. The active subwoofer light is continues to be on even though it’s on auto mode.
    My questions are:
    Is it a defect?
    Will it damage the subwoofer?
    Is it recommended to power off the subwoofer when the amp is on standby mode? Otherwise the speaker system plays awesome.

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