Sub's for Magenpan 3,7

I have a pair magenpan 3.7 I thinking of adding a couple of subs, I have a Weiss 202 dac Pass Labs 350.5 amp,what should I been looking for in a sub and how do I intergrate them into the system wiring, do I need a pre-amp?I never done this in two channel system before, so all comments welcome
Nice system K-Rose. You don't need a preamp if you buy REL subs. And connection is really easy.

Besides the obvious sound of real sub bass, I look for adjustments in the crossover and high/low outputs at small increments. And being a woodworker, I also looked at fit and finish and how the cabinet bracing of the sub is manufactured. That is just as important to me.

REL Sub-Bass system connects to your Pass Lab amp speaker outputs via the Neutrik Speakon-type connector (3 wires). You'll connect the REL to the same amplifier output terminals as the magenpan 3.7. In other words, the signal sent to the REL is exactly the same signal sent to the speakers, allowing for seamless integration.

More on REL connecting up can be found here:

REL Manual

I added a REL R-218 to my 3.7R's in August. I highly recommend you give a 218 or 328 REL a try. Lapierre's guidance on hook up is accurate. If (like me) you use fully balanced monoblocks, hook up is a little tricky, but still no big deal and the REL documentation is well written.
From the manual for the X350.5:
Some powered subwoofers require an audio signal ground reference and their makers may suggest that a black speaker terminal is where this voltage reference might be found. On complementary designs, which would be typical of all power amps produced by Pass Laboratories™, this is an incorrect and unsafe assumption. On all Pass Laboratories™ power amplifiers a reference of 0 volts will be found only at pin 1 of the XLR input or at the shell of the RCA input.
Reference connections for these devices require special consideration when used with our product. If you have such a device, and wish to use it with our product, please contact our Foresthill, California factory for specific instructions.... you have been warned.
A way to implement this, assuming that the connections between the DAC and the amp are via their XLR connectors, would be to solder the ground wire from each sub to the ground sleeve connection of an RCA plug, with nothing connected to the center pin of the RCA plug, and to insert that RCA plug into one of the RCA jacks on the amp. It would probably make no difference sonically whether you use separate RCA plugs for that purpose for the two subs, or just a single plug with the ground wires from both subs connected to its ground sleeve.

The (ungrounded) signal input wires from the subs would of course be connected to the positive (probably red) output terminals of the amp. Since you are intending to have two subs, you would probably want to connect both the left and right signal wires from the left channel sub to the left channel positive output terminal of the amp, and both the left and right signal wires from the right channel sub to the right channel positive output terminal of the amp.

Alternatively, an acceptable approach MIGHT be to connect the low level inputs of the subs to the RCA outputs of the DAC, while connecting the Pass amp to its XLR outputs. Before doing that, however, Weiss should be asked to confirm that those two sets of outputs are designed to be used simultaneously. It is conceivable that the RCA outputs are driven by the same output stages that drive one of the two signal polarities that are applied to the XLR connectors, in which case this approach would not be a good one.

A third approach, if the sub provides XLR inputs (such as some of the JL Audio subs do), would be to use XLR y-adapters, such as these, to route the DAC's XLR outputs to both the Pass amp and the subs. The low output impedance of the DAC probably makes that a more reasonable approach than it would be with a lot of other equipment, although it is still conceivable that this approach could compromise, at least slightly, the quality of the sound that is heard through the Maggies.

The latter two approaches, of course, would sacrifice the sonic advantage that was mentioned by Pierre of having the power amp in the signal path to the subs.

-- Al
Thank you all, very helpful information I will start the search for subs, hopfully I will be happy with outcome, The Maggies are not bad on there own but looking a for little morejust not right at this stage.
Thanks again
Whatever sub you use, get a DSpeaker anti-mode 8033. I use the 1.7 Maggies with a Paradigm servo 15. I had been looking to change subs but this sub device made a huge improvement. I do like the idea of a servo unit with these quick speakers, but a friend is happy with his 20.0 speakers and the top Hsu sub. He also tried a DSPeaker unit and was amazed. I would suggest you get Mye stands for your 3.7s. Have fun!
I had 2 REL Stentors for several years but had reliability issues so went to a JL Audio sub that was quicker and went deeper and have never looked back!

(dealer disclaimer)
Hi. I have 3.7 and HT and happy to explain how I integrated Velodyne dd+15 sub in no problems.
Iam currenty using Mye stands change the fuses and using vahalla jumpers, I strugling to be happy.Tb subs have come up on my search any comments,I am loss and struggling to get these to sound there best.Podeschi I will send you a PM thanks for that.
Hi K. Rose,

Sounds like a great setup. Getting a good sub to mate with the Magnepans is critical. I would suggest you think of three options:

1) REL: I echo the sentiments of many that you should audition REL's offerings

2) If you are looking used, I would highly recommend Revel Performa B15 or B15a subs. I personally own the B15 and it is an amazing, tight, and fast sub. But, it's big with a 15" woofer.

3) JL Fathom. I hear this sub a few months ago when I auditioned a pair of Wilson Sasha speakers. The sub lives up to all the reviews.

I know there are likely plenty of other good subs out there, but having auditioned Maggies myself, these are the three subs that I think will be real winners in the setup.
Magnepan now has woofers try a pair of the DWMs
they will work great.
Were you awear of these being available?
Magnepan dealer
No I wasn't, I also came across brand called TBI, they also look very intersting will have a look at the Magenpan site at there subs also and check other recomedation given
The DWM is a small section of the bass panel from the 20.1's. It only goes down to 40 Hz. I'm not sure its going to add that much to the 3.7's.
((I'm not sure))
I thought so
Do you think Magnepan after 30 plus years might have worked on this,knows how to
transition their bass to sound natural?
Cheers JohnnyR
Please do not sub to Maggies 3.7. I think you should care of cables. Try transparent, purist audio and you'll see it's a big defferent in lows.