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silvertone
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What's the story with Rockport Technologies?

I live in the Dallas area and have not found a dealer yet to hear the Mira's in person. I have heard these are just as good as the Wilson WP8's..Are these speakers as good as the hype surrounding them?

I saw an older review from JA on one of their models, but looking at the graphs it appears that the high frequencies are rolled off, hence giving a false sense of softness and warmth. Can anyone comment on the engineering quality behind this company. Many thanks in advance.

rupert
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Re: What's the story with Rockport Technologies?

I've heard them and would highly suggest an audition.

Fremer reviewed the Antares model a while ago, and liked it a lot.

BTW, if flat frequency response is the main criteria , the Wp8 is out-another post has it 15 db up at 80hz (similar to JA's measurements in WP's review)

jkalman
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Re: What's the story with Rockport Technologies?


Quote:
BTW, if flat frequency response is the main criteria , the Wp8 is out-another post has it 15 db up at 80hz (similar to JA's measurements in WP's review)

If you are referring to my room measurements, that isn't a W/P8 issue it is a room mode. There is a wave reinforcement between 60-80 Hz in my room. It happens with any speaker I place in that position in my room. The following measurements are considered fairly representative of the speakers measurments by Wilson Audio I believe (at least the NRC of Canada has been mentioned by Wilson Audio in the past as being more representative of real world use with how they measure their speakers than other methods being used), as they are taken at 6.5 feet away in an anechoic chamber (the listening window measurement in particular might be most useful). Here is the link: National Research Council of Canada measurements of the W/P 8.

As you can see in the measurement link, the frequency response is only around +2 dB (or less) above the sensitivity of 91 dB at 80 Hz. Thus, it is only +2 dB (or less) off a flat frequency response at those frequencies without room mode interference at a distance of 6.5 feet.

You might be interested in reading about the NRC as well, to get a sense of what they do for all industry in Canada! NRC link.

To be more specific, my tray ceiling is around 9' high and the soffit is around 7' 4" high. The two of those together, plus the +2 dB FR on the W/P8 combine to make that lovely slope seen in my FR graphs. The 9' area creates a reinforcement at 62.8 Hz and the 7'4" dimension creates one at 77.4 Hz.

Also, my other major dimensions (my room is irregular so it gets more difficult than a simple rectangle problem with modes) are 18' and 33'. So the first mode on the 18' dimension is 31.4 Hz, the next is 62.8 Hz. The third mode on the 33' room length is 68.5 Hz.

So there are three modes in almost the same exact spot in my room due to the dimensions. The FR in the 60 Hz to 80 Hz region would be a lot worse if my room weren't also irregular in shape! I am considering using some kind of parametric EQing to fix the issue. I really don't have any other choice, as this problem is a function of the room.

jkalman
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Re: What's the story with Rockport Technologies?

My bad, four not three, modes clustered in a close area. BTW, I moved the seating position back and managed to balance out the reinforcement a little better with the surrounding FR by raising other areas of the FR around it up more. I'm still in the process of moving the mic around and taking 1" increment ETF5 measurements between the 1.1:1 to 1.25:1 listening position distance from the speakers (actually, to be truthful, I didn't even start until responding to this thread, I got lazy....). I don't see it geting much better though, since it is a room mode issue made a lot worse by two room dimensions sharing a common multiple (9 and 18) and consequently reinforcing each other at a certain point where the wave lengths are too large to easily fix with treatments. Imagine how much worse it would have been though, if my room were 100% rectangular and not irregular, at least because of this, the higher frequency room modes get broken up a bit.

Elk
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Re: What's the story with Rockport Technologies?

I can't imagine there is any speaker out there that is either plus or minus 15dB within its range of reproduction when measured probably.

I haven't heard the Mira's but I would love to - they look great.

Jeff, take heart that at least it is not a trough in your frequency response - you can never fill these in no matter how much you through at them. I recall you were interested in trying the Rives unit for the bass. Have you done so?

jkalman
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Re: What's the story with Rockport Technologies?


Quote:
Jeff, take heart that at least it is not a trough in your frequency response - you can never fill these in no matter how much you through at them. I recall you were interested in trying the Rives unit for the bass. Have you done so?

Yeah, it is a consideration still. I was sort of hoping to keep the two channel equipment section completely pure. I do have the Meridian room correction for the surround setup, though they use notch filters that likely aren't as extreme as parametric EQ. I can do two channel sound through the Meridian as well and compare the two systems and see if I like the difference between them enough to push it further. If I keep the two channel setup pure, it still leaves me without frequency response correction for LPs... And, if I use the Meridian for the LPs it will digitize the signal before outputting it again in analog, LOL... Oh well.

The bass management crossover alone on the Meridian 861 helps with the really bad mode reinforcement at around 60-80 Hz, and helps with the nulls as well a little by balancing out the signal.

The other solution, that would require that I use the Sub30s as a pass through, is to use the Sub30 EQs instead. That would give me three parametric EQs per main speaker at 80Hz and below. The issue with this is that I would then have no way to listen to the Watt Puppy 8s on their own without subs....

This is the bass management and non-bass management comparison.

I don't want to hijack this thread, so I will post this in my W/P 8 thread as well in case anyone wants to respond further with any ideas. God knows, I could always use more options to consider!

BTW, I should mention, that comparison might look better now if I redo the sound measurements as I have fine tuned the levels and distances since that was originally taken. Also, it added a null as well in the above comparison, so perhaps you just can't win in these situations.

Elk
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Re: What's the story with Rockport Technologies?

Interesting stuff.

But yes, back to the Miras!

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