Magical Merlin Mystery?

There were several reasons I bought a new pair of Merlin’s flagship speakers, the VSM-MXR (or MXM, as they may yet be called — don’t ask). One of which was the joy I got from the VSM-MME speakers I sold to buy them — those were just great speakers. Second was the salesmanship of Mr. Merlin himself, Bobby P, who claimed that the new VSM-MXRs would make my beloved MME speakers “sound broken” as the MXRs were so much better. Last, and probably most important (to me, at least), I wanted to put together a whole rig that let me have my cake and eat it too.

Let me explain.

I like bass. Lots and lots of clean, tight, musical bass. Which presents a problem.

It seems that speakers are pretty cheap to make. It’s a box, some wire, some (generally speaking) cheap electronics parts, some drivers. Shazam! Speaker. As I’ve explored elsewhere, you can expect the relationship of a speaker’s MSRP to more or less track with the price of the parts … up to a point … and then things get hinky.

Specifically, that point appears to be about 30Hz.

What you want in a speaker is the ability to produce the full audible band, faithfully and electrifyingly. Sadly, most speakers do not (can not?) produce the lowest frequencies with any degree of verisimilitude. I’m sure there are a lot of great reasons for this, but I don’t really care other than for this fact — if you want to buy a “great loudspeaker” that can produce 16Hz (lowest organ note) at the same SPL that it can produce a tone at 1200Hz, that speaker is liable to cost you well north of $25,000.

Like I said, hinky.

Now, as any home theater aficionado will tell you, 16Hz is outside the range of human hearing — but it will do really nifty things to your window casements. The device you need to create this magical effect? A subwoofer. In fact, get two, because not only are these things awesome, they’re pretty cheap too. IMO, the best sub on the market (and not just bang-for-your-buck) is the Rythmik Audio F12G, an $800/unit marvel. Add a pair to the best monitor speaker you can afford, and you now have — you guessed it — subterranean bass on top of your monitor’s native awesomeness.

As I was a big fan of Merlin, and I wanted Deep Bass, even Bobby P. could put two and two together to sketch out a 2+2 channel rig that really ought to knock me right out of my socks — and compete (by bandwidth at least) with stratospherically priced expensive speakers that got the same frequency response in a more traditional package.

I should have known.

The problem is that f****** Merlin BAM module. The BAM, now in it’s “Master” incarnation, is part filter, part equalizer, and fully external to the speakers themselves. Essentially, the unit sits “somewhere” in the signal path and provides a dramatic boost to the performance of the speakers. In all fairness, it does exactly that. But you’ll need an extra set of interconnects — which with $30 interconnects from Blue Jeans Cables isn’t a big deal, but if you’re buying the Merlin recommended Cardas Clear interconnects at nearly $2k a pair, this might be a nightmare. And then there’s the problem of where you put the damn thing.

Bobby recommends you put it in front of your preamp. Say what? Yes. Ideally, the BAM sits between the source and the preamp. The filtering ought to be done as early as possible in the signal chain. Which is fine if you have one source. And I do! I have one DAC, one SACD player and one turntable. Which means that I’m in trouble — or I’m buying two more BAMs (not!). Alternative #2 is to put the BAM between the preamp and the amp — works great! Well, at least in theory. In practice, the hum from my speakers is telling me that I’ve got either a ground loop or something (hinky!) is going on. A quick chat with Bobby reveals that #2 is “not recommended” for just the reasons I was discovering (hinkiness). Instead, the BAM must be put into the tape loop. I rewired everything accordingly and presto! Hum was gone — and in fact, the speakers suddenly sounded more relaxed and the bass reached a bit deeper.

But here’s the problem — the BAM is also a filter. Which means that the system is no longer sending signal below 29Hz anywhere!

If the BAM is between the preamp and the amps, a preamp with two sets of lineouts (like mine) will be able to create one path through the BAM for filtering and one path straight to the subs for full range goodness. Snapping the BAM into the tape loop (and activating it) means that the entire preamp only sends abbreviated signals anywhere — the two outputs are mirrored.


[EDIT] Well, it seems that I was a bit premature. I missed something:

The “filter” in the BAM is not a brickwall filter — it’s a 6dB/octave roll-off. Verified this with a Stereophile Test CD — I sent some 25Hz signals through the system and the woofer cones on the subs thrummed like they were supposed to. So, yes, they’re getting something below 29Hz. I spoke with Bobby P. about “my issue” (he’s the one who recommended this setup!) and he reassured me that there are lots of folks that are using subs with VSM speakers and doing so successfully.

So, yes. There is a problem and the BAM+subwoofer “solution” is suboptimal. But perhaps not fatal. Bobby recommended looking at an EQ device, like the Velodyne SMS-1, as an option to try and adjust the output to cope with the attenuating signal — and help smooth out the 25-35Hz dip.

This solution, of course, introduces other potential problems. We’ve only managed to move the problem around a bit! So, this new EQ device, does it sum the output (ie, take stereo inputs and make them mono)? Can it handle more than one subwoofer (I have 2)? Is it going to cost more than my subs?!?

Time for more research! Just when you think you’re out, they pull you back in ….

About Scot Hull 1062 Articles
Scot started all this back in 2009. He is currently the Publisher here at PTA, the Publisher at The Occasional Magazine, and the Executive Producer at The Occasional Podcast. There are way too many words about him over on the Contributors page.


  1. Well what happened next? i am looking to up grade my system. (Counter point DC-10 DAC, Meitner Pa6i Preamp, Behringer DEQ2496, (Plinius 8200 Amp, and other amps more vintage amps, Linn Isobarik or Celestion Dittion Studio monitor 66) I found a local pair of Merlin VMS (Revision unknown at this time) and I am going to check them out. But I do like the bottom end. What did you find out?

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