November 16, 2009

Tear Down These Walls. PMC OB1i Speakers.

The PMC OB1i speakers takes up residence in my audio cave.

I was a little apprehensive about receiving the PMC OB1i speakers in to my audio cave. It just seemed a little too big for the room. James of AV Designs re-assured me, "they'll be alright!, plus they're the smallest PMC's to have that mid range dome that you so lusted after". It was a time after I had listened to Mr S's formidable Bryston, PMC based HT/music system(see home visit, featured in September). Ohh... that kinda puts everything in to perspective.

That mid range dome in the middle is special, it sounds special!

James thoughtfully arrived with the speakers, helped me to haul them two flight of stairs up to my audio cave and aided in initial set up. These PMCs are heavy. Moving them about is really a two man job. But once in place, minor adjustments are do able on my own. Speaker reviews are really hard work, and they take up a lot of set up time too.

The PMC OB1i standing tall. The listening position ideally should place ear height in between the tweeter and the mid range dome.

I hook up the PMCs to my Pass Aleph 0 mono blocks and away we played some music. It sounded very promising already. James remarked that it could only get better, he then left me to my own devices. I played around with speaker placement trying to reduce the effects of my room's 48Hz excitation mode. I eventually settled at 4o inches from back wall and 18 inches from side wall, measured on the outside corner at the back of the speaker box. I then played around with toe in, but just like my earlier experience with the GB1i, I thought the OB1i sounded best without toe in, just firing straight a head in to the room. Once the speaker position is confirmed, I then attach the speaker base spikes on the out riggers and put the spike coasters under them to protect my wood flooring. Just in case you're wondering, my room measures 10 x 12 x 9 ft(W x L x H).

The PMC OB1i allows tri-wiring or tri-amping, i.e. has 3 pairs speaker cable binding post per speaker. I did not have the cables to exploit this option, but what I did was that I could use this flexibility to further fine tune the speaker's tonality. I first opted to have the speaker cable connected to the high's binding post, bearing in mind to lean out the bass response in my room, by boosting the treble just a bit. However, subsequent listening had me settling for a more even tonality cross speaker wiring, i.e. the negative to the high's binding post and the positive to the mid's binding post(see picture below). A word on the speaker binding post, for a speaker of it's stature, WBT style binding post would be preferred.

The speaker cable binding post used are of generic variety. Priced at RM$25k, WBT style ones would be nice!

With the final position and wiring options taken care of, I proceeded with some serious listening. Coming to the PMC OB1i from the Marten Design Form is a very drastic change in sound. The PMCs have reasonably sweet and extended treble, just like the GB1i. The mid range has warm open clarity, yet solid density and very stable imaging properties. The bass, from a transmission line tuned enclosure is effortless, dives deep, yet remain articulate.

The unique ATL, or Advance Transmission Line tuned bass port.

The OB1i does sound stage in my room as laid back as the Marten Design Form. However the stage width extends way, way away from the speaker's side wall. Combining that width extension with the laid back presentation gave an impression of the walls of the room has been torn down. The musical event happening in time and space just outside the room's boundaries. These big boys really do disappear in to the room, sonically speaking, despite their bulk.

The veneer finish is excellent. Note the out riggers at the bottom, where spikes are attached for stability.

The OB1i is highly transparent yet reasonably forgiving to poor sources, i.e. recordings. For me, this is a positive trait as I have many poorly recorded but good enjoyable music, like pop/rock recordings. Having said that, the PMC OB1i doesn't short change excellent audiophile grade materials either. There's also a certain PRAT factor going here, which makes every CD, an enjoyable listening experience.

The OB1i, being the biggest speaker to yet entered service in to my room for the past 2 weeks or so have made me feel the smaller speakers that I was using to sound edgy all the time by comparison. It'll be hard to revert to those smaller speakers.

I later hooked up the Krell S300i integrated amp(review to come next) to power the PMCs. Rated at 150W @ 8 ohms, the Krell was truly up to the job of powering the 87db sensitivity OB1i. With the Krell amp, I found the perfect synergy for the PMC OB1i. The speakers were already performing admirably with the Pass Aleph, now truly comes to spectacular life. The bass was immediately tighten, to the point that when compared to the Pass Aleph, which the bass notes does tend to miss a note here, and lag a bit there. Only in direct back to back comparison with the Krell, that I realised the Achilles heel of the Pass Aleph. With the Krell amp, the transient response and dynamics headroom was a major sonic draw card. I found myself looking for all the most dynamic sounding CDs to play on this system. The PMCs can take a lot of punishment with no complains.

One thing I really enjoyed with the Krell/PMC combo was the kick drums and percussion instruments. The kick drums really have the realistic kick ass, rocking quality that will please even the hardest of rockers. Having said that, the PMCs can also sound sublime with more sentimental paced music. All said and done the PMC is an all round performer of the highest order, irregardless of music genre. It just gets to the heart of the music and allows it to flow out naturally.

Another look at the PMC OB1i.

I am really impressed by the PMC OB1i. They're big, yet comfortably fit in to small rooms and bring down the wall boundaries. They can sonically disappear almost like a mini monitor and when partnered with a grippy amp(i.e. amps that have high damping factor) the PMCs really come in to it's own. The OB1i is also sonically transparent enough not to favour any music genre, which means excellent musical all rounder.

If you've RM$25k to burn on nearly full range speakers, and plan to house them in to small or medium sized rooms, I really think the PMC OB1i is a top contender indeed, based on my experience of it in my small audio cave. I highly recommend it.

PMC speakers sold by AV Designs, contact James, tel no:03-21712828

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