Brief Impressions: MBOW1 DIY speakers designed by Dennis Murphy
Aug 12, 2004 at 7:22 PM Thread Starter Post #1 of 3

ooheadsoo

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General First Impression
Even with my current amplification chain (wooaudioI and power section of NAD integrated that none of you bought) these speakers are detailed, detailed, detailed. The very first thing I noticed was that the presentation was completely different from my NHT Pro powered monitors. The NHT Pros have a ZZZZZIIIIIIIIINNNNNGGGGGG up top, I guess similar to grados. The mbow1's lack that zing, so when I first heard them, I though to myself..."THAT SOUNDS WRONG!" Well, it turns out, something was shorting inside the cabinet and the tweeter wasn't working!
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But back to my point, when I had the tweeter working, I had to do a double take to make sure the tweeter was working. Where was the ZZZZIIIIIIIINNNNNNGGGGGG? No zing. was seriously wondering if I had wired the xover correctly at this point. But strangely, all the details were there...in fact, more detail than I had ever heard with this amplification chain. After taking a step back from the NHT Pro's perspective, I realized that the mbow1's were making all this detail with absolutely no zing up on top.

General highs/tweeter impressions
Now does this mean that highs are not extended? Not at all. I fired up Stan Kenton's "Maynard Ferguson," Maynard Ferguson's "Maynard Ferguson." Arturo Sandoval's "Maynard Ferguson," (the best version) and it was all there. Fired up some string stuff like Antares' rendition of John Mackey's Breakdown Tango. Violin is smoother and more natural sounding up with re: to the upper harmonics. There is definitely more texture with solo strings like violins and cellos than I am used to. Not even close to what I heard with Stuartr's vinyl setup over at Orpheus's joint at the last SoCal meet, but definitely more than what I heard with my own setup, and I had believed that my current setup was incapable of producing more detail and texture! Voices have lost their harsh edge compared to the NHT Pros. Definitely less sibilance with the mbow1.

Imaging
Imaging is a step beyond what the NHT Pros did. Firstly, the NHT Pros were no slouch in imaging. Everything always floated firmly between the speakers except for stuff that was panned hard left or hard right. There's no way, IMO, that headphones can match this kind of imaging. The depth from the mbow1's are even more pronounced and tantalizing. I struggle to hear depth from my NHT Pros. A lot of it has to do with my setup, no doubt. I have my speakers stuck in the corner of my room. I have treated the front and left walls with rigid fiberglass panels and it has helped a lot to clear up room/reflection related imaging issues, but depth is not a strength of my system. With the mbow1's depth is more apparent. I don't exactly hear stuff coming from 20 feet beyond my rear wall like some people say they hear from their speakers, but the relative distances are more clear than before. In some cases, I can walk up to my speaker and have completely no idea where the sound is coming from. I normally set 1m from my speakers and the imaging is stunning. They were stunning with the NHT Pros as well, for that matter, but it's slightly different with the mbow1. Sometimes I can put my ear an inch from one speaker and the sound still sounds like it's coming from 6 inches away behind the plane of the speaker's baffle. When playing a mono test tone, I can put my ear right on top of the speaker and it's still coming from the middle between the speakers.

Sweet spot
I've always considered sweet spot to include imaging, but apparently most people only consider the tonality. Well, my cabinet's baffle edges were rounded over on all 4 edges to reduce diffraction problems. Tonally, I can move around all over the place without a great change in the tone of the speaker. If you look at the graphs here: http://murphyblaster.com/content.php?f=MBOW1.html you can see that the dispersion of the woofer and tweeter are both excellent and the xover has caused no anomalies. It sounds that way too. I can move a lot and the tonality of the instruments does not change significantly. As for the imaging sweetspot, it is also slightly different. I believe it is due to the extraordinarily good dispersion of the Hiquphon OW1 tweeter. With my NHT Pros, if I moved an inch to the left, the center image would shift to the left by, well, I'm projecting here to the plane of sound behind the speakers so it's not accurate, say, 3 inches. With the mbow1, if I shift to the left an inch, the center image only shifts about 1 inch. The right image never completely detaches from the right speaker. This combined with the larger sweetspot makes me a happy DIYer. It's still perhaps not the locked in the center imaging I have heard from speakers with differently loaded dispersion methods like an effective wave guide, but it's very very good. It's also been a while since I listened to something like that so I'd like to listen again some time and form a better informed opinion.

Bass
Here's a real anomaly. According to the designer of the speaker, he tuned the box to 70hz and the port to around 57hz. He has measured and can hear close to no output at 50hz.

When I first tested my wiring of the speaker, I thought the bass was boomy. Two things: at that time I had not yet applied any cabinet damping and the speaker was on the floor near the corner of my room. I applied blackhole5 and got my speakers up into position once I finished them. The boominess is now gone but the bass is on the warm side. I tested the bass performance of the speakers using pure signal generators and warble tones to reduce room loading. The bass starts to go down in level around 70hz, but BARELY. It's basically flat out to 50hz, ALMOST flat out to 40hz, and significantly down by 35hz, but still making viable output. Most impressive. In fact, I have the feeling that the designer of the speakers doesn't quite believe me
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I had a HECK of a time integrating my subwoofer without muddying up the bass too much. My sub only goes flat to about 32-33hz before dropping off like a rock! *sigh* Now I need a better subwoofer. I find this to be astonishing bass output. I chalk it up to two things, my wooaudio-I preamp, my NAD amplifier's power section, and probably the most important factor, my room. In fact, I still hear the same bass anomalies on the mbow1's that I heard with all the rest of the speakers I have ever heard in my system: null of at least 5db at 95hz - 110hz, peak of over 9db at 140hz - 160hz. The detail of the bass is slightly more eloquent with the subwoofer off. I had to really dial the sub down to get it in balance. I think I have it tuned now where the depth of the bass is enhanced by the sub but clarity is not overwhelmed. However, in my room with my amplification, the bass performance in deep and extended enough that you could get away without a sub for most musical performance. You've got to hear this to believe it. I used my brother as a pair of impartial ears and he hears what I'm hearing. The test track I use to test bass transient response is "Flim" from The Bad Plus. To test adequate bass extension and impact for classical music, I use the big bass drum hits on Verdi's Requiem from BAS's test disc. For more impact on more modern music, I use Keiko Matsui's "Dream Walk" which has a deep grooving bass line right at the beginning.

Dynamics
Slightly more microdynamics than with the NHT Pros. Leading edges on piano sound more defined. Still, I'd reserve judgement on this section until I get better amplification. This NAD is sounding pretty darned good right now. The question is, "how much better can it get?"

Concluding B.S.
I don't know how much true value my new DIY speakers have (mbow1,) but they are very nice speakers. Cost of parts alone were around $630 but I could have cut a few corners on some things. I decided to go all out on the x-over and I spent way too much money on the crappy paint finish that I botched. It's a lot better than my NHT Pro powered monitors, IMO, which originally retailed for about $1300. I mean, for those of us that care about the details and nuances of music, it is A LOT better. I'm eager to hear how these speakers will sound on some cheap solid state amplification because my wallet is now empty and I want to sell my more expensive gear
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What's wrong with the speakers? Bass is still a bit on the warm side. Depth is not like 20-40 feet deep like I have heard some people claim with their speakers. Perhaps with more experience, I could point out more faults. I'm fairly sure that more detail could be brought about with different amplification.

Thanks go out to Dave Ellis, Dan Wesnor, Danny Richie, and, of course, Dennis Murphy.

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Aug 12, 2004 at 11:56 PM Post #3 of 3
Thanks! I'll keep that in mind about the polyurethane...but at this point, it's "live with it" or "sand the crap out of it and start over with bondo city." The finish is really quite bad, especially the cabinet that I had someone help me work on because I was impatient after over 18 hours of hand sanding and wanted to start building my xovers
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Not a slam on him. I may wax it in a few weeks (this is auto paint after all
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