A number of industry leading subwoofer manufacturers recommend using high-level, or speaker-level, connection in order to derive the best performance from their product and the speaker system being supported. There are many valid reasons for this, most simply expressed by the thought that the subwoofer is being sent precisely the same signal as the speakers, which allows for better integration of speaker and sub due to timing and timbre characteristics being identical.
Standard recommended practice is to connect the red subwoofer cable to the positive speaker terminal of one channel, the yellow lead to the positive speaker terminal of the other channel, and the black lead being connected to whichever of the negative or outputs is most convenient.
Note: our recommendation is to always connect the black wire to the ground collar of an RCA plug or the ground post of an XLR and connect to any unused input on the amp or preamp, rather than using the negative speaker output.
However, certain amplifiers’ speaker output topologies, including some from Primare, prevent the use of this connection scheme, particularly with a single subwoofer, resulting in the standard high-level connection scheme not providing the correct signal to the subwoofers.
In those instances where the standard high-level connection scheme is not an option, the most obvious alternative is to use low-level stereo connection from the pre-amplifier or analog outputs of the integrated amp or preamplifier, allowing for excellent performance.
Note: for the I15 Prisma MK2 and SC15 Prisma MK2 the ANALOG output will need to be set to PRE.
This means you will run your main speakers full range, as designed, with the sub crossed over, using its Low-Pass Filter, to match the natural roll of the main speakers. This allows the sub to focus on true sub-bass frequencies providing not only the obvious low bass extension you are looking for but also more natural overall tonal balance and soundstage openness.
Note, as a rule, the Low-Pass Filter should be set at a value approximately equal to (or below) 70% of your main speaker's lowest frequency response. For example, your speaker's frequency response goes down to 43Hz. 70% of 43Hz equals 30.1, so you should set the subwoofer's low pass filter to 30Hz, with final tuning done by ear.
However, some subwoofers have only a single low-level input. So, if a pair of subs is not an option, it is possible to use a Y-adapter to create a single input, but this runs the small risk of creating a mono signal for the main output as well. The easiest thing to do would be to connect an inexpensive y-adapter and cable to try the experiment and see if this is the case in your system.
If this does not work, we have had many customers reporting excellent results connecting to one channel, either one of the low-level variable outputs or, for high-level connection, the left speaker output.
Below are listed the recommended connection schemes for Primare amplifiers:
Stereo Amplifiers
A60/A32/I30
One sub-bass system in stereo configuration:
- Red to one positive speaker terminal
- Yellow to the other positive speaker terminal
- Black to ground on RCA collar or XLR pin into any unused amp or preamp input or chassis ground
I15/I25/I35/A35.2/I32/A34.2
One sub-bass system: use stereo low-level pre-amp output connection.
Two sub-bass systems:
- Right channel connection:
- Red and yellow cables connected to Red (+) speaker output
- Black to RCA collar or XLR ground pin to unused input on amp or preamp, or float if no hum is heard from the sub and it is getting signal
- Left channel connection:
- Red and yellow cables connected to Black (-) speaker output
- Black to RCA collar or XLR ground pin to unused input on amp or preamp, or float if no hum is heard from the sub and it is getting signal.
- Notes:
- phase setting will need to be the opposite of right channel setting
- combined yellow and red wire bundle may provide too much single input. If this is the case, simply disconnect one of the cables, red or yellow, and cut off the bare wire (or cover with electrical tape) on the unused cable.
A35.2/A34.2 Bridged
When a pair of A34.2/A35.2 amplifiers bridged to mono, one subwoofer can be connected in a stereo configuration using the following scheme:
- Red to the positive speaker terminal of one amplifier
- Yellow to the positive speaker terminal of the other amplifier
- Black to ground on RCA collar or XLR pin into any unused amp or preamp input or to chassis ground
When using a pair of subwoofers with a pair of A34.2/A35.2 amplifiers bridged to mono connect using the following scheme:
- Red and Yellow to the positive speaker terminal of one of the amplifiers
- Black to ground on RCA collar or XLR pin into any unused amp input or to chassis ground of that amp or to a preamp input
- Red and Yellow to the positive speaker terminal of the other amplifier
- amp input or to chassis ground of that amp or to a preamp input
- Black to ground on RCA collar or XLR pin into any unused amp input or to chassis ground of that amp or to a preamp input
Multi-Channel Amplifiers
In the case of Primare multi-channel amps a variation of the standard connection scheme can be used as long as careful selection of specific output channels is observed.
SPA22/SPA23
Main front left and right channels - the red speaker output is active, and the black speaker output is ground, so the follow this connection scheme:
- Red to one positive speaker terminal
- Yellow to the other positive speaker terminal
- Black to ground on RCA collar or XLR pin into any unused amp or preamp input
Surround left and right channels - the black speaker output is active and red speaker output is ground, so follow this connection scheme:
- Red cable to right Black [active] speaker output
- Yellow cable to left/Black [active] speaker output
- Black cable to right or left Red [ground] speaker output [or RCA collar/XLR ground pin to unused input on amp or preamp]
- Note: phase setting may need to be the opposite of the main channel setting
Centre channel - the black speaker output is active and red speaker output is ground, so follow this connection scheme:
- Red and yellow cables connected to Black (-) speaker output
Note: combined yellow and red wire bundle may provide too much single input. If this is the case, simply disconnect one of the cables, red or yellow, and cut off the bare wire (or cover with electrical tape) on the unused cable.
- Black to RCA collar or XLR ground pin to unused input on amp or preamp
- Note: phase setting may need to be set to the opposite of the main channel setting
A30.7 multi-channel amplifier
Note: channels 1,2,3,4 are in phase, and opposite to 5,6,7.
- 1,2,3,4 – the black speaker output is active, and the red speaker output is ground:
- Red cable to right Black [active] speaker output
- Yellow cable to left/Black [active] speaker output
- Black cable to right or left Red [ground] speaker output [or RCA collar/XLR ground pin to unused input on amp or preamp]
- 5, 6, 7 red speaker output is active and black speaker output is ground:
- Red cable to right/Red [active] speaker output
- Yellow cable to left/Red [active] speaker output
- Black cable to right or left to Black [ground] speaker output [or RCA collar/XLR ground pin to unused input on amp or preamp]
This results in the following system connection recommendations:
- 5, 6, or 7-channel system
- Channels 5 and 7 main left and right – standard hook-up scheme.
- Channel 6 centre - standard hook-up scheme for single sub per channel.
- Channels 1,2, 3, 4 rear channels in either a 5, 6, or 7.1 system configuration with connection as described below:
- Red cable to right Black [active] speaker output
- Yellow cable to left/Black [active] speaker output
- Black cable to right or left Red [ground] speaker output [or RCA collar/XLR ground pin to unused input on amp or preamp]
- Bi-amp main left and right 5-channel system.
- Channels 1,2, 3, 4 front left and right channels with pairs of outputs connected to bass and treble to respective inputs of the partnering speakers according to the following scheme:
- Red cable to right Black [active] speaker output
- Yellow cable to left/Black [active] speaker output
- Black cable to right or left Red [ground] speaker output [or RCA collar/XLR ground pin to unused input on amp or preamp]
- Channels 5 and 7 rear channels - standard hook-up scheme.
- Channel 6 centre channel – standard hook-up scheme for single sub per channel.
- Channels 1,2, 3, 4 front left and right channels with pairs of outputs connected to bass and treble to respective inputs of the partnering speakers according to the following scheme:
- Note: phase setting for channels 1-4 may need to be set to the opposite of channels 5-7.
A35.8
Speaker connection polarity for both stereo and bridge modes is indicated below with “+” for positive or hot connection and “–“ for negative or cold connection.
- Red and yellow cables connected to (+) speaker outputs
- Black cable to “–“ speaker outputs, or:
- RCA collar/XLR ground pin to unused input on amp or preamp
- float if no hum is heard from the sub and it is getting signal
- SP1 Red – / Black +
- Bridged Red + / Black –
- SP2 Red + / Black –
- SP3 Red - / Black +
- Bridged Red + / Black –
- SP4 Red + / Black –
- SP5 Red – / Black +
- Bridged Red + / Black –
- SP6 Red + / Black –
- SP7 Red – / Black +
- Bridged Red + / Black –
- SP8 Red + / Black –
- Notes:
- Phase setting for even numbered channels (2/4/6/8) may need to be set to the opposite phase of the odd numbered channels (1/3/5/7).
- Combined yellow and red wire bundle may provide too much single input. If this is the case, simply disconnect one of the cables, red or yellow, and cut off the bare wire (or cover with electrical tape) on the unused cable.
- Left and Right speaker pairs are recommended to be connected to either odd or even unbridged output pairs.
SPA25 Prisma home cinema processor integrated amplifier
Speaker connection polarity for both stereo and bridge modes is indicated below with “+” for positive or hot connection and “–“ for negative or cold connection.
- Red and yellow cables connected to (+) speaker outputs
- Black cable to “–“ speaker outputs, or:
- RCA collar/XLR ground pin to unused input on amp or preamp
- float if no hum is heard from the sub and it is getting signal
- Front LR and Centre: Red + / Black –
- All others: Red – / Black +
- Note: phase setting for front channels (L/C/R) may need to be set to the opposite of odd numbered channels (surround and height speakers).
June 2024
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