Injecting one sub to Benchmark system…

Noob here and just hooked up my new Benchmark AHB2 and DAC3 HGC with pair of Totem1 bookshelf speakers.

I have a Velodyne SPL-R series subwoofer and would like to connect this. I’m seeing a lot of varied advice on the web on how to do this and thought I would come here for better advice.

Not even sure if the sub would connect to the preamp or the amp….any suggestions?



Your HGC should have two sets of RCA outputs, and one set of XLR output. Use a set left and right of RCA outputs to your subwoofer input. As for economical custom length RCA cables try bluejeans cable.

I would get a Dspeaker 8033 which will not only connect it but EQ it for integration with the speakers and your room.

["kota1 I would get a Dspeaker 8033 which will not only connect it but EQ it for integration with the speakers and your room.’}

In 2005 Velodyne introduced the SPL-R series. Equipped with twelve internal Sweep Tones, six bands of EQ, four alternative EQ Presets, Four position Phase, Volume, Night setting, Auto On/Off and Mute all via Remote Control.

Connectivity via Speaker level Inputs, L/R RCA Inputs and Outputs and Calibrated mic.

Thanks M-DB…. My model is the SPLR series, model is the SPL 10 RCH.

Don’t have the calibrated mic but it should be easy enough through experimenting to get it integrated with my speakers.

Going to try that today.

just got the system hooked up (without subwoofer) and to be honest I’m underwhelmed ….I know this is a great little system for my small apartment but over the last year I’ve been trying out different high end headphones and since I enjoy “excitement” and bass over something like the HD800s headphones I settled with the Fostex TH900 headphones which I really love, especially for their bass.
I understand a system vs headphones is a different experience but the sound enjoyment level just isn’t there on this Benchmak system (yet).

Part of the problem is not being able to play at a volume I prefer without bothering neighbors. The other problem is room treatment and the small size of the room.

I ordered thick curtains for all walls with pairs of curtains on each wall so I can open them so as not to deaden the room too much and I’m still experimenting with this.

The room is only 8 feet wide so I’m probably losing sound stage. I brought the speakers closer to the listening chair to make a “triangular” listening point (sitting same distance as the speakers are apart) and this made a big difference and now the speakers have “disappeared”. Still, I’m far from content.

Its hard to be objective (does this sound good or is it awful) since I haven’t been able to listen to others similar systems in a perfect room and maybe I’m expecting too much based on my great satisfaction with the lively sound through these headphones. Maybe I’ll get a bit closer once I hook up and dial in this subwoofer and work more on room treatment.

thanks again



Kota 1 - thanks, but I’m trying to work with what I have here in Brazil and buying more gear and sliding through customs is out of the question for me at this point.

@thomastrouble , you are in trouble. If you have any idea what you are listening too, trying to EQ a sub without it's calibration microphone is a nightmare. Second issue is that one sub is never enough. The minimum is two. But, have at it. It will be a fine learning experience. The sub connects to your preamp then the R/L outputs go to your amp, a very fine one at that. Then, start twisting knobs and listening. With a properly integrated sub woofer system the subs should seem to disappear until a real low note comes along. If you hear the subwoofer as a distinct entity you have more work to do.

If you want to do this right for less get kits from Parts Express, a bass amp and a digital two way crossover with bass management like a MiniDSP. Do not use a plate amp. Get a commercial sound reinforcement amp like a QSC. 

Thanks myjostyn, I’m just finding that out now as I hooked up the sub about a half hour ago. To add to the confusion I’m still trying to really get my room treatment sorted out and get rid of muddiness without the subwoofer. Something just isn’t right there, just way to muddy. It’s getting to the point where I don’t even know if it’s possible to get this system sounding good in an 8x12 room.

quick question….on the Velodyne I’m going into the LFE and not the speaker level inputs. On the outputs on the DAC3 there are two pairs, both pairs are white outputs while on the sub inputs there is a red and a white….how do I tell which of the two whites on the DAC3 go to the red on the sub or does it even matter?

thomas, I love mijostyn. His system is terrifically satisfying. Judging by that system and his unbelievably well appointed wood working shop I'd say he has a financial foot up on most of us here. I know I'm envious.

Yes, you can absolutly have excellent bass reproduction at the listening position with one subwoofer.

To the left of the four white RCA outputs on your HGC. The upper two RCA's are labeled L (Left) and the bottom two are labeled R (right). The bottom R output will connect to the red (Right) input of the subwoofer.

Below is the Velodyne SPL-R series Manual 

Does the layout on the Front Panel Features of your SPL include the (4) MIC input as in the drawing on page 5 of the SPL-R Series Manual? 

There are two different looking Remote Controls both have the same function buttons as the one pictured on page 11 of the SPL Manual. Do you have the Remote Control? 

Hi M-db, thanks a lot for that!

My remote for the sub doesn’t seem to be working so I popped an email off to Velodyne today to see if they can sell me one as I’m flying back to the US tomorrow for about a week.

Front panel - mine has no switches on the front at all. I’m guessing mine is probably over 15 years old.

re. two subs in my 8x12 room - im wondering if even one is too much!

Anyway guys, thanks a million for all the input, I’m flying for 30 hours tomorrow (with stop-overs), so won’t be checking in here, just don’t want anybody thinking I’m ungrateful.

thomas, SPL 10 RCH doesn’t seem to bring up any information. Though I did find this which may help.

Below is a link to an earlier SPL User’s Manual

The Sub on the cover lacks the Front Panel Features. Notice on page 2 the MIC INPUT (7) is on the back panel. On page 6 the earlier Remote Control is pictured. If these differences match your SPL you may simply need to replace the Remote Control’s battery and purchase a calibrated mic to perform the EQ feature.

Lacking in all Velodyne User’s Manuals until their Plus series is the need to preform the Crawl Test to locate your rooms loudest bass mode where the sub should be located. This is critical for single sub use.

Velodyne’s onboard EQ is easier to use, far more detailed and includes the four EQ Presets compared to the suggested MiniDSP and DeSpeaker.

FYI, Velodyne Acoustics is now located in Hamburg, Germany.

I was in this situation in about 2006 with a dac1 and a sub.  The new models may be different but I thought back then that I really lost something by having the DAC output going to both an amplifier and a sub.  I'd at least experiment with getting an adapter and running the sub from the headphone out.  I eventually got a regular preamp and I thought that was a substantial improvement in definition through most of the frequency spectrum.  I'd also experiment going power amp to sub because that definitely won't take away from the low level signal that is easy to mess up.  

I think the time has arrived for people to experiment with cheap performance oriented electronics.  I've recently bought a couple of <$150 Schiit products and they're great.  At work I have a Fiio x7 to Schiit Magni+ powering DCA Aeon Noires and it's great.  Nothing about that setup bothers me and I'm pretty easily bothered.  If a preamp died on me I would not hesitate to try a $599 Freya S.  

Hi Jon…that’s a new one for me - running from headphone out!

im still in the very early stages and want to work with what I have right now.

I have been reading a lot of good things regarding these Schiit products. Funny, the DAC 3 has a great reputation but when I plugged my headphones in i was surprised that I much prefer my Ifi Gryphon portable amp/DAC. I think the Benchmark might sound a bit too clinical for me but I’ve yet to try this with a pair of HD800s headphones I have coming. So far I’m much preferring what I hear from my headphones and Gryphon over the Benchmark audio set-up. Still, I have work to do dialing this system in.

@thomastrouble I also didn’t like the headphone amp sound of DAC 3 HGC. It was too clinical for me as well. 
As far as sub connection, what @m-db said. 

Benchmark runs both XLR and RCA outputs at the same time. You can use one of those to the subs and the other to your amp. You can also go in and adjust the voltage of the XLR with the pads to match the RCA voltage if you need to use an XLR to RCA adapter. It is clear in the manual how to adjust them 

@james633 is absolutely correct, and I’ve been using this exact configuration for quite some time with dual passive TV-12 Ultra drivers.

Those darn XLR Attenuator pads / jumpers I have moved around more then I’d care to admit. It has been a while though, but by golly, it’s fun to play.


The idea behind running the headphone out for the sub is that having the pre-outs running two sets of wires at the same time and into 2 amplifiers at the same time is harder for the dac to power than a single set of wires and amp.  Running from the headphone amp to the sub would, I think, reduce that because the headphone amp is its own separate amplification from the preouts.  And it's something you can try for the cost of a $5 headphone jack to rca adapter.  

IMO it's a mistake to not try a regular preamp with the Benchmarks.  While there may be a tiny loss of transparency I found a preamp was overall a pretty big improvement.


Your last paragraph is perfection!

You’ve now mentioned “twice” (or has it been once) using headphone output. Funny, for I’ve also done such configuration on an older Vintage piece of gear which had no pre-out. Receiver > Amp. What can I say other than I love my tone controls, and desired to still utilize them with the added headroom. Likely somewhat of a impedance mismatch but hey, it worked.