April 30, 2001
Subject: Biwiring vs. biamping
I'm using two Krell KAV-250a amps as
dedicated monoblocks to drive a pair of B&W Nautilus 802s in biwire mode. Using this
approach, the KAV-250as are rated 1000Wpc into an 8-ohm load.
The B&W 802s are rated 8-ohm nominal (3-ohm minimum),
crossover frequencies are 350Hz and 4kHz, and they have a 91dB sensitivity rating. B&W
also recommends a maximum cable impedance of 0.2 ohms.
The Krell KAV-250a amps can also be used in a biamp mode,
albeit with a lower power rating (each channel 250 watts into 8 ohms and 500 watts into 4
ohms).
The B&W manual indicates the 802s are capable of being
driven in a passive biamp mode. And I remember reading the B&W Nautilus 801 Stereophile
review that recommended driving those speakers in a biamp mode to get the most out of
them.
I've read a number of very complimentary reviews of the
KAV250a, but always in the stereo mode. I haven't been able to find any information on
whether anyone driven the B&W 802s with the KAV-250as (or any other amps) in a biamp
mode. What were the perceived advantages over biwire mode? I'm also trying to determine if
the reduction in watts/channel in the biamp mode would result in less dynamic range.
I'm also considering using true monoblocks in a biwire mode
(Krell FPB 250Mc'), but their considerable expense is a deterrent. My listening room is
only 15' X 18', but the ceilings are 12' high and the listening room is really part of a
much larger open area in the center of the house. So I believe I need to use rather
large-wattage amps to achieve live listening levels. I use my system for both critical
listening as well as home theater, so I'm very interested in achieving the best sound
possible within my financial constraints. I would very much appreciate your advice
regarding biwiring vs. biamping, particularly if the biamp mode resulted in using less
power/channel.
Len
Hi Len:
Passively biamping your speakers will prove a
revelation to you. While the 802s do want a lot of power, I should think that a
Krell KAV250a would do quite nicely. So unbridge the Krells and try it. Best of
all, the experiment will be quite cheap to try -- especially if you can borrow the second
set of speaker cables from a friend.
Let me know what you think after you've tried it.
ATB...Wes
April 26, 2001
Subject: Crossover frequency
I'd appreciate if you could help
provide me an answer to the following question. I recently purchased a pair of PSB Alpha
Minis. I'm running them using an Infinity subwoofer that I purchased a while back. My
question is how to set my sub's crossover frequency to match the Alphas. The specs on the
Alphas list a response of 68Hz-21,000Hz and a LF cutoff -10dB of 55Hz. Also, how should I
set the volume control on the sub? Any help you can provide is greatly appreciated.
Jonathan A. Zalkin
Hi Jonathan:
You're asking for a simple answer to a complex
question. What prevents a simple answer from working is the room you're listening in and
the positions of the speakers and woofers relative to one another and relative to you.
Here's my suggestion. Start by playing the PSBs
full range -- don't use the subwoofer's high pass filter. Set the subwoofer's crossover to
about 60Hz and experiment with Hz increments higher and lower. When you hear the woofer
doubling the speaker, turn the crossover frequency down 5Hz. And once you've established
the crossover frequency, back off the sub's output until you no longer quite hear it.
That's roughly where you want to leave it, although small adjustments may continue to be
necessary.
ATB...Wes
April 23, 2001
Subject: Combining the best qualities of two systems
I have a question for the "Ask
Wes" column that I was hoping you could answer. I have a modest system -- B&W
DM602-S2 speakers driven by a Yamaha RX-596 two-channel receiver, fed by an old (about 12
years old) JVC CD player, all connected with Monster Cable (there is also a Music Hall
MMF-2.1 turntable in the system, but I am concerned with CD sound here). A relative of
mine has a system that is even more plebian in pedigree -- a late-'70s or early-'80s
Technics receiver (wooden enclosure, silver face, analog tuning -- you know the deal)
driving a pair of old, large (10" woofers) three-way Marantz floorstanding speakers
that a previous owner had modified by installing Pyle tweeters and Infinity crossovers
(mounted on the outside of the back of the cabinet). His source is a Nakamichi CD-4 CD
player.
I am actually quite happy with the performance of my system
-- for the price it has a clear, open sound with good definition of detail, but my
relative's system has a certain richness to its sound, a certain lush, unhurried,
laid-back quality that mine seems to lack. It is most apparent on acoustic jazz, which
happens to be the kind of music I listen to the most.
Can you recommend something I can do to gain some of the
best qualities of his system without sacrificing the best qualities of mine? I can do
approximately one upgrade per year, up to $1k (US) per upgrade.
Thanks very much in advance!
Regards,
Tony
Dear Tony:
Beats me -- I would expect your relative's system
to sound awful, but perhaps he knew what he was doing when he hacked his loudspeakers.
Sometimes, some systems just have a certain synergy that you'd never be able predict in
advance. I'm listening to a $3500 system consisting of the Sony SCD333ES, an Arcam A-85
integrated and a pair of Epos M15 floorstanding two-ways that just sounds shockingly good
-- far better than anything I would have ever expected at this price point. Who knew?
Your 602s are a great loudspeaker, so you probably
aren't hearing even a tenth of what they're capable of. I'd look at your source -- perhaps
the Sony SCD333ES would be a great solution. It sounds great on CDs and plays DSD SACDs
that sound better than anything you've ever heard. And after that, think about replacing
your Yamaha -- but bring home anything you're thinking about buying and compare it to your
Yamaha. That unit's a classic with surprisingly good sound. If you trade it in, be sure
it's a trade up.
ATB...Wes
April 22, 2001
Subject: Speakers with Musical Fidelity A3 amp
I am planning to get the Musical Fidelity A3 amp with a set
of Linn Ninkas or Rega Jura speakers. I have auditioned Audio Physic and Sonus Faber
Concertos also. Are there any other speakers I should audition that, in your opinion, rock
with the A3 before I take the plunge?
Please advise.
Sanjay
Dear Sanjay:
Those are all solid choices that'll work well with
the A3. Let me know what you end up with and what tipped the scale for you, OK?
ATB...Wes
April 21, 2001
Subject: Room set up
I've been following your career through the many stereo
publications you've been affiliated with. I am going to finish my basement soon and need
some advice about audio-room design. Dimensions of room: the maximum ceiling height is
approximately 8 feet. Maximum width is 13 feet, and length is up to 25 feet. What is the
optimum size within these restrictions? Should I use special dry wall or double thickness
with insulation between layers? The floor is concrete now. Is concrete with area rug good,
or is fully carpeted better? Should I have 45-degree corners to eliminate corner trapping
of bass? Or use Room Tunes and keep square corner angles? Your advice would be greatly
appreciated. My system includes a Teac T1 transport, EAD7000 D/A converter, Audio Research
LS5 preamp and Bryston 4Bst amp. My speakers are Acarian Alon 5 Mk II, my interconnects
are Cardas Cross and Golden Cross. My speaker cable is Acarian Systems Tri-wire.
Anxiously waiting some guidance,
Dr. David Stern
Hi Doc:
As you have probably guessed, there is still some
controversy over the proper way to build a dedicated music room. I suggest you give Carl
Marchisoto at Acarian Systems a call and talk to him about building the room to best show
off his loudspeakers. Carl's a very smart guy and will give you lots of good -- and
good-sounding -- advice.
ATB...Wes
April 20, 2001
Subject: How to judge without listening -- Musical Fidelity
A3CR
I read your review on Musical
Fidelity A3CR power amp, and I was also recommended this amp by a friend of mine.
Unfortunately, this amp is only sold here in the US by Audio Advisor (a patron of your
site).
Now, my question to you is, most audiophiles stress the
importance of auditioning the system before one buying it; with the MF A3CR only sold
through online mail order, how can I judge this amp, such as the sound and build quality?
Your comment and reply is much appreciated.
Regards,
Sam
Hi Sam:
If you're lucky enough to have a helpful dealer
nearby, you should patronize him and take advantage of his knowledge and services -- which
should include demo loans. If you don't have such a dealer in your area, you need
to use other avenues to find out about the gear you might like to own. This includes mail
order outlets, such as Audio Advisor. Audio Advisor and certain other mail order vendors
offer 30-day satisfaction-or-your-money back guarantees, which allow you to audition gear
for the price of shipping the gear to and from your house. That's not free, but for those
items you are seriously interested in, it offers a way for you to be sure before you
commit. Also, Audio Advisor has announced that Musical Fidelity components will be sold
via brick-and-mortar dealers.
ATB...Wes
April 19, 2001
Subject: Shahinian Obelisks
I've been scouring the web for help
without success so far, but...
I am listening to a Meridian CD through Naim amplifiers and
Shahinian Arc speakers. I recently heard the Obelisks and decided immediately that this
was the next step. The obvious hurdle, however, is the price, so I have decided to try my
hand at making some. The woodwork is no problem. The electronics (if I had a diagram) are
not much of a problem as I'm OK with a soldering iron. The problem is finding someone who
can identify the bass/mid/tweeters used in the Obelisks and who can provide a crossover
diagram.
Any answers or pointers in the right direction would be
gratefully accepted.
Thanks
Wyn
Hi Wyn:
I have to assume that you have no qualms about the
niggling intellectual property issue of Shahinian's patent either. Sorry, I can't help you
there -- there are plenty of DIY designs made freely available. Why don't you make one of
them instead of ripping off a trouper like Dick Shahinian? Stereos sound better with good
karma, you know.
ATB...Wes
April 18, 2001
Subject: To upgrade or not to upgrade
I have a couple of questions I'm hoping you may be able to
help me with.
I've been thinking about (wondering if I can) upgrading my
turntable. It is an older Denon DP 3000 direct drive with a Mas (?) tonearm and a cheap
($30) cartridge. I guess what I really want to know is if it's worth upgrading (or
possible to), or would I be better off saving the $500 to buy an MMF-2? My other quick
question is: Have you ever heard of Belden speaker wire? A buddy who used to sell stereo
gear gave me some and although it sounds better than the regular zip cord, I've never
heard of it before. He says it's supposed to be good stuff though. Is Belden 9184
shielded?
Thanks for your time and great website,
John Anderson
Hi John:
My experience with Denon TTs is that they're not
all that easy to successfully modify. Sell yours and use the money towards your purchase
of the MMF-2, which will reward you with better everything.
Belden is pro-audio cable and yes, it is well-made
stuff. I've used a lot of it, especially for carrying digital data. According to Belden's
website, 9184 uses an aluminum foil/polyester tape/aluminum foil shield for a two-pair
solid core 22AWG tinned copper wire set.
ATB…Wes
April 16, 2001
Subject: Review of Sony CDP-CX400
I have just read your November 2000
review of the Sony CDP-CX400, having unsuccessfully looked for a review of the CDP-CX450,
of which I own two. I find interesting your comment that you would like to load info
directly from the Internet like the Pioneer does. I previously had two Pioneer 300-CD
changers, which I gave away when I couldn't use TitleTrack Jukebox and CDDB on my
Mac to download info, and bought the two Sonys instead. Using a Slink-e device, I have
been able to automate the input of information quite successfully. On the other hand, I
have been searching for user comments on the features of the CDP-CX450, as I have become
quite frustrated trying to program the units for random play. I can successfully play
random selections from a single CD, but the units shut down after playing a single
selection when I have stipulated that I wish random from all CDs. Based on my previous
experience with other Sony products, I halfway expect that some features don't work the
way they are promised to. Are you familiar with these units at all?
And one other comment. I normally listen to classical
music, and don't find it the least bit offensive to listen to multiple movement works in
segments. It is not much different from the programming at a concert, where portions of
many works may be heard in an evening. I also find it eliminates the effect of my mind
expecting to hear a specific selection following the current one just because the music
programmer arranged them that way.
I would be interested in your comments on the CDP-CX450.
Margit
Hi Margit:
I discovered the Slink-e myself and have been using
it for a while now. It answers the majority of my questions concerning multiple
mega-changers, but, like you, I find the existing software to be a tad glitchy. I'll cover
some of this in my review of the Slink-e, which will be posted on May 15th. Stay tuned.
ATB…Wes
April 10, 2001
Subject: Audio burnout
I'm suffering a bit of burnout with
my current system. I'm just about at the point now of selling off all my current gear and
starting from scratch. The system I've been thinking of putting together consists of
Dynaudio Contour 1.3 Mk II speakers, Musical Fidelity A3CR preamp and power amps (liked
your article, had a listen and loved them), and my old trusty Meridian 506 18-bit CD
player. What are your thoughts on this system? I know the Dynaudios need a fair amount of
current and power to make them jump, so I thought the Musical Fidelity would provide that.
On the front end, do you think it would be worth keeping the Meridian and adding the
Perpetual Technologies duo to do upsampling and interpolation or get rid of it altogether
and get an SACD player? I have about 400 CDs that I like to listen to.
Thanks in advance
Anthony Colbert
Dear Anthony:
Audio burnout is a major problem that seldom gets
discussed. Your system seems as though it should sound quite good, so I'd look at what
you're trying to achieve with it. Relax, play your favorite CDs without any expectations.
Do this for a month without worrying about soundstaging or depth of field or anything
other than how much you like your favorite discs.
At that point, audition an SACD player and see if
you don't respond favorably to it. Buy (or borrow) a DSD-recorded SACD for the audition.
If it inspires audio-lust, buy it and don't look back. If you get a strong
"ehhh" reaction, order the Perpetual pair on spec and try that.
Either way, you'll get an improvement in your
system, but only you can judge which sounds better to you.
ATB...Wes
April 5, 2001
Subject: Tubed preamp hiss
Hello, Wes. I'm a longtime subscriber
to Stereophile and The Abso!ute Sound and an admirer of your contributions
to both. After years of reading, auditioning and saving, I have finally pieced together a
system I am 99.9% happy with. You have had something to do with some of these choices (you
may recognize some components that you have given favorable reviews to over the years). My
system consists of:
- Music Hall MMF-5 turntable
- Linn Genki HDCD CD player
- VTL Maximal tube preamp
- Proceed HPA-2 250W dual-monaural power amp
- Magnepan MG1.6/QR speakers (biwired)
My problem is with the preamp. The Maximal was purchased
used. It is about 12 years old, looks to be in fine shape and mostly sounds great. It has
what looks to be a cheap after-market power cord hard-wired to it, and I am hearing a hiss
through the speakers when the Maximal is in the audio chain. Is it likely that the power
cord is the culprit, or are one or more of the tubes going bad (or something else I
haven't thought of)? If it is the power cord, do you recommend a particular brand that
could be hard-wired?
Thank you for your advice and your devotion to the audio
community!
Craig Provonsha
Hi Craig:
The power cord is an unlikely candidate, but after
12 years, a tube change is probably in order.
ATB...Wes
April 1, 2001
Subject: Amps
I have had Apogee Stages powered by a
Krell KSA-150 for a number of years. I have managed to acquire the subs to make a
MiniGrand. Question: What should I use to power the subs? Should I switch the Krell to the
more efficient subs and seek a new friend for the Stages? If offered the choice of either
a Krell KSA-250 or a KAV-250 at similar prices, which would you opt for? What is the
difference? Or should I go for something else?
Secondly, any opinion of the Infinity IRS Epsilon. I heard
a pair the other day. They sounded similar to Apogees. How would you rate the MiniGrands
versus Epsilons? Though I could not do a direct comparison, I am intrigued at a possible
purchase. Would Krells be appropriate companions or would "softer" C-J be
better? (I know that tubes are meant to be better but replacements would be a
problem/hassle.)
Thank you for your advice/time.
Anthony Mulliner
Dear Anthony:
I've heard the MiniGrands sound good, but they are,
by all reports, a bear to set up properly. If you can get the subs to blend seamlessly
with the Stages, you're a set up wiz!
If the subs are more efficient and you're happy
with the Krells, I'd say look for an amp to drive the subs -- any decently powered
solid-state amp should do.
As to your second question, sorry -- I haven't
heard the Epsilons.
ATB...Wes
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