Q&A # 293 - June 15, 2002

Staff

Q Are there any sound quality differences between coaxial and Toslink optical cables?

A I have not heard any differences, but it is time to run some objective tests with instrumentation, so we will do that and report on it.

Q In Q&A 281, you encourage someone seeking to run two center speakers from one to channel to "connect them in series" as opposed to parallel. Now, I'm sure this sounds like a dumb question, but would that also apply to surround speakers? I would like to be able to have "7.1" setup from a "6.1" receiver (two rear-center speakers).

A For mass market receivers, yes, you should connect the two speakers in series to the single amplifier output. With 8 Ohm speakers, that will give you an impedance of 16 Ohms instead of 4 Ohms, and your receiver will thank you for it. Note that series operation should only be done with identical speakers. This is because if the impedance of one speaker does not match the other (curve, not just nominal value) the voltage drop between the speakers will vary with their proportional impedance to each other, and they will both alter each other's frequency response. If the impedances are virtually identical, then the voltage drop will be virtually half across each at any given frequency, and the frequency response will change little between them.

Q I was told that if I have a subwoofer in my system, I should set all my speakers to "Small" and the subwoofer to "On" with the receiver bass management menu. This is supposed to reduce strain on the amp and speakers for producing bass, and therefore better sound quality is achieved. Do you suggest this? My main speakers are floor-standing and can handle bass (Mission M74). If I should set all my speakers to small (including mains), what crossover frequency should I set on the subwoofer (Yamaha YST SW-320). If on the other hand you suggest that I set my mains as "Large" on the receiver, then what crossover frequency should I set on the subwoofer?

A With bass management that has selectable frequencies down to 40 Hz, setting floor-standers to a low frequency can work nicely. However, most mass market receivers have a fixed crossover frequency at 90 Hz or 120 Hz, and this is too high. With my Theta Casablanca II, I use a 50 Hz high-pass crossover frequency for all the speakers, even though they are full range. I then have all my subwoofers set at 50 Hz low-pass. There are emerging receivers with variable low-pass settings, but most don't have this flexibility yet. Assuming your receiver is a fixed frequency type, use the "Large" setting for your speakers, and a 50 Hz low-pass setting on your subwoofer control panel.

Q I'm looking for some help finding guidelines/directions/methods for building in-wall speaker enclosures. I have a new house that is in the framing stage and (based on negotiations with my wife) would like to use in-wall and in-ceiling speakers for the home theater area. I will sorely miss my "real" speakers, and am trying to uphold sound quality as best I can.

A In-wall speaker technology is a field unto itself. Don't buy a driver that was meant for a regular enclosure and just install it in the wall. There are many factors to contend with. However, it is not going to be a problem for you if you do your homework, which it appears, you are already doing. Check out such sites as Sonance  (http://www.sonance.com), SmartHome (http://www.smarthome.com/speakers.html), AV123 (http://www.123av.com/Speakers.asp), etc., which can help. Don't rule out getting the speaker with its enclosure already built, but designed with the center-on-center distance between wall studs, and thin enough to be mounted there. That is probably the way I would go rather than trying to build the enclosure along with fitting it into the wall.

Q I bought XXX speakers a year ago on my somewhat limited college budget.  Now I have a bigger budget and want to get YYY speakers. Now, the XXX speakers do sound good but I am told that the YYY do sound better.  So  I took a listen at the local shop, and they do sound great but I can't  compare the two unless they are side by side which is impossible. Could you  possibly give me some reasons why YYY is better than my XXX? I have been told about better imaging, crossovers, cone materials, and better  vibration and resonance control of the YYY. I listen to some classical  music but mostly hard rock, and techno like Crystal Method.

A I replaced the brand names you mentioned with the XXX and YYY because your situation applies to all brands. There are lots of things that go into a product design, including parts quality. But, it is more than that. Modular appearance is a marketing thing that everyone is getting into these days, to compete with the XXX line of speakers you have now. In general, the small modular speakers are more oriented for consumers who have limited space, such as an apartment, or just don't want to have big speakers overpowering the look of their living room. Sometimes, the modular speakers are priced pretty high, because they spend money in high profile magazines to advertise them to people who are busy and on the run all the time. It is not necessarily so, but can be the situation. My suggestion to you is, now that you have heard so many opinions on what is best, you take your XXX speakers into the dealer showroom, and have your sales rep set them up next to the YYY. Take some of your favorite CDs with you, and have him switch back and forth between the two sets while the music is playing. Listen to some other brands and models while you are there. You never know what might strike your fancy.

Q Are there any progressive scan DVD players for under $500 that do not have the chroma bug?

A The Panasonic RP56 is under $200 and does not have the chroma bug. In fact, Panasonic players have never had it. The Apex 800 does not have it and it is under $200. Neither do the JVCs. Also the new Samsung 721M kind of does not have it most of the time (there is a bug, and that will get fixed soon). The Denon DVD-1600 we tested recently, passes that test in that price range, and has DVD-A. I am sure more are to follow. Several manufacturers have been sending us their preliminary production runs of new models for our comments. Some have passed, and some have not. We are hoping the problems we found can be corrected before they release them to production.

Q I just recently compared two different receivers, a Yamaha 800 and an Integra 6.2. My question is that when using the sub output on both receivers the Yamaha seemed to put out twice the bass compared to the Integra which seemed to be very weak on the bass end of things. Does this seem normal? Or should the sub-out produce close to the same level of bass? The speakers I am using are Paradigm Monitors, with a PDR-12 subwoofer.

A The output of the subwoofer jack will depend on the crossover frequency it is using along with other factors of bass management. Some will add all the bass together from all the channels regardless of whether or not you have the speaker setting to "Large" or "Small". Others only add the bass into the subwoofer pre-out for a channel where you have selected "Small". The difference in bass output is normal.

Q I feel as though I've gotten myself in mess with my current speakers and subwoofer. My front speakers are Polk RT2000Is. The center and surrounds are smaller Polk speakers as well, and the sub is a Mirage BPS-410. My problem is how to set up my system for proper operation. If it matters, I am using a Sony DA777ES receiver, which seems to offer plenty of options to tweak.

Currently I have the Polks configured as the manufacturer suggest, using the supplied jumpers to send a signal from the speaker wire to the powered subwoofer section instead of using an RCA cable. The sub pre-out jack on the receiver is connected to the LFE input on the sub which bypasses the sub's crossover. In the past I have experimented by running the subwoofers on the Polks from the receiver's sub pre-out. Which is best?

I do own a Radio Shack sound level meter to calibrate the system, but how do I adjust the level on subwoofers in the Polks so that those speakers are balanced, and then how do I adjust to sub to blend in the system properly?

Presently, I have the main speakers set to "Large" on the receiver, and the center and surrounds set to small with the crossover set to 80 Hz.

A The RT2000s are full range speakers. Leave them set to "Large" on the receiver, and use the subwoofer pre-out from your receiver to the subwoofer. Don't connect the speaker jumpers on the speakers to the subwoofer at all. Set your subwoofer crossover to 50 Hz.

� Copyright 2002 Secrets of Home Theater & High Fidelity
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