Q&A # 272 - January 18, 2002

Staff

Q I have a pair of 12" 1000 watt Rockford Fosgate Hx2s in my room. I have everything set up right, but I was wondering, will the speakers be louder in dBs, if I ported the box they are in? The box is one single wooden box with the speakers facing out sitting right next to each other, but there is a wooden wall in between the two speakers, in the center. If porting the box anywhere, whether it be to the outside, or in between the speakers inside the box would make a difference, I am curious.

A Whether a speaker enclosure is ported or sealed is a factor in the overall speaker design goals, not just how loud it can play. The stiffness of the cone is part of the design, ported or sealed. When a speaker driver is used in a design plan, the driver's Thiel parameters are consulted, which are a bunch of numbers that specify the driver's characteristics. For example, look at these specifications for the NHT 1259 12" subwoofer driver (http://www.speakercity.com/nht_1259.shtml). The Q values in the specification column determine the optimum size of the enclosure and whether sealed or ported would work best.

Your Rockfords might play louder if you cut a port, but it would undoubtedly compromise the sound in other ways. It could lose some deep extension, and it could produce more harmonic distortion. It might become boomy and lose bass tightness too. A port is more than just a hole. It has to be the right size, and usually there is a tube of a specified length attached to the port on the inside. So, I suggest leaving the speaker enclosure as is.

Q I recently swapped out my Anthem MCA-5 amp for a Parasound 2205AT. I was told by my dealer that the Parasound has a "high bandwidth" and will easily pick up any AC noise (i.e., it needs clean power). I'm finding out that he is apparently correct. I tend to like to run amplifiers directly to the wall as I find that my Monster HTS3500 seems to do horrible things with music when I plug amplifiers into it (decreased soundstage, lack of midrange/midbass bloom, slightly digital "analytical sound; these artifacts are apparent even at relatively low volumes. I've heard other people complain about this, unfortunately AFTER I bought the Monster).  With the Anthem plugged into the wall, I heard absolutely no hum coming from the speakers. The Parasound on the other hand causes the speakers to emit a noticeable hum. When I plug the Parasound into the Monster, the hum is noticeably reduced but the overall musicality of the system suffers (as described earlier). Do you have any suggestions besides installing a dedicated electrical outlet (did I mention I live in an apartment and unfortunately the system shares the same circuit as my two aquariums with power compact fluorescent lights and filters along with my computer and all of the room lights)? Do you think the Rotel RLC-900 would be sonically neutral yet reduce the hum?

A Fluorescent lights and incandescent lights on dimmers can cause lots of noise to get into AC lines. In your case, it may be a simple ground loop that is causing the problem. Some amplifiers are subject to ground loops while others don't seem to be. I would suggest getting balanced power to connect your system. The most economical ones can be purchased from companies like Balanced Power Technologies, reviewed HERE, but if you prefer something more substantial, try the Smart Theatre Systems GC120, reviewed HERE, the Equi=Tech 2Q, reviewed HERE, or the PS Audio P1200, reviewed HERE. Since you are connecting power amplifiers, get the 1,000 watt or higher wattage version of whichever unit you buy.

Q I am looking for something I can put between my VCR and Pro Logic Receiver that will keep the volume from going up during commercials.

A The problem here is that commercials pay for TV programming, and something that reduces the power of commercials to communicate their messages to consumers is frowned upon by the TV industry. That is why you don't see gadgets on TVs that keep the volume at a preset level, which would not only be useful for commercials, but also for keeping the same volume when you switch between different channels.

Q I've got a new Toshiba 36" TV and DVD player (not progressive scan). I currently have them linked via an S-Video cable setup (as I do my satellite receiver). My question is, would the ColorStream component video cables produce better video than the S-Cables?

A First, ColorStream is only a marketing term that Toshiba uses for component video. Secondly, component video cables use the same kind of conductors as S-Video cables, but with component, you have three conductors (besides ground), while S-Video uses two. But, yes, component video will give you a better picture. If your player has component video outputs, and your TV has component video inputs, use them.

Q In your review of the Panasonic DVD RP-56, you mention that although there is no DCDi or other markings indicating the use of the Faroudja FCI2200 de-interlacing chip, the player does indeed incorporate that chip. When I opened the cover of a Philips DVD Q-50, I could see "SAGE" printed boldly on the chip, but no such labeling on the chip in the Panasonic unit.  Should I still be confident that the Faroudja chip is used? (i.e., what markings betray this?) I tried calling Panasonic to confirm this, but was told that they will not release such information to me.

A The main thing is the performance. If you get the DCDi performance, their chip technology is present. I have often encountered the lack of markings on chips. It is just one of those things that involves manufacturing rather than showing logos to consumers. The marketing of DCDi is something just now beginning to be presented to consumers by putting DCDi logos on the front of the players.

Q I have been having a very hard time choosing a receiver. At first, I was looking at the Integra (9.1, and 8.2) and the Denon (5800, and the 4802), and just can't decide on which company, and then which model. Then I found out that Integra is made by Onkyo (I just didn't realize), so if I go with Integra, why not go with Onkyo (989 or the 898), because of the price. Now here's the thing. I'm kind of on a budget (I say kind of because I'm willing to spend more if the features are that much better, i.e., 9.1 instead of 8.2, but if the higher model is just higher powered with a few more inputs, then I'll go with the 2nd model). So, here is what I'm looking for, and hopefully you can help: 1) It needs to be upgradable; 2) I'm not too concerned with power or inputs and outputs (just something within reason, with enough digital ins/outs without going overboard); 3) It has to be 6.1 or 7.1 with at least 6-multi-channel analog inputs; 4) It would be very nice if it could convert video (S-Video to composite or vice versa); 5) I would be willing to pay much more if it converted to Firewire (I also do video editing, and my camera is Firewire-equipped); 6) Surround formats are important (thus the ability to upgrade). Years ago I bought a Yamaha 2070 (which I love), which was a little costly, but is now outdated. I would hope that my next purchase would have a little more "staying power".

A The Integra units have larger power supplies, so if you are not going to buy outboard power amplifiers, then get the Integra. Otherwise, the Onkyo units should be considered, with the idea that you might get an outboard power amplifier down the road. Many receivers let you connect composite and S-Video sources with everything going to the S-Video monitor output. Just check with the receiver's specifications and also ask the dealer. Request a demo just to be sure. Firewire is for a complete digital video signal, including the sound that goes with it, not just playback of sound. Future receivers could very well have the processing to take a digital camera's input and output the video to your TV while playing the digital sound track through your speakers, but that is down the road a few years, I think. It might be through Firewire, or DVI, or even SDI.

Q Presently, my system consists of the following Carver components: CT-17, TFM-55, TFM-35, TFM-25, one (1) Silver 7T and a set of AL-III speakers. I am using the TFM-55 to power the ribbons and TFM-35 to power the subs on the AL-III. My plan is to upgrade the CT-17 to a DD/DTS processor/preamp to take advantage of the TFM-25 for surrounds and Silver 7T for the center. My question is: with a budget of $1500, what would you recommend for surround and center speakers that match the power of the TFM-25 and Silver 7T, respectively, and match (tonality) with the AL-III?

A The Carver AL-III speakers are ribbons with a cone woofer in the base. Ribbons don't have enclosures per se, and thus, they have a tonality all their own. You will need to get more ribbon speakers, or planar speakers, to go with your AL-IIIs. Eminent Technology (http://www.eminent-tech.com/) makes speakers that have planar technology, which are similar to ribbons, and they are priced reasonably. You should also look at Magnepan speakers (http://www.magnepan.com/1-800-474-1646/index.html).

Q First, I'd like to say that you guys Kick-Butt!

As the founder and CEO of my own web site (ComputerJobs.com since 1995), I  can say without doubt that you guys have created a truly valuable Internet service among many miserably created, over-hyped, VC-funded disasters that were just trying to make a quick buck. You also kill your printed competitor's magazines hands down!

Second, I'm stumped trying to find out if Component Video Inputs on receivers (Re: Denon AVR-4802) are capable of handling HDTV material. I don't have HDTV yet (DishNetwork requires a second dish set to an alternate satellite), but want to upgrade my AVR-3600 to a 4802 so that I can run my component video signals through the receiver instead of directly to my Sony 7" CRT projector (VPH-D50HTU) which has BNC-type jacks for HTDV and other high-res sources (like my new XBOX!).

Here's the problem: The manual for my Sony projector gives different specs for the component video inputs based on the type of source, and I have no idea what the differences are or if a receiver can correctly handle/process them. For example, the manual states the following based on the type of source: (also see
http://bpgprod.sel.sony.com/bpcnav/app/99999/12/97/49338.99999.print.BPC.html  for the same specs on Sony's newest projector).

Input A:

Analog RGB / Component : BNC
R / R-Y : 0.7Vp-p �2dB positive, 75Ohms terminated
G : 0.7Vp-p �2dB positive, 75Ohms terminated
Y / G with sync : 1Vp-p �2dB sync negative, 75Ohms terminated
B / B-Y : 0.7Vp-p �2dB positive, 75Ohms terminated

HDTV (Y/PB/PR) : BNC
Y : 1Vp-p �2dB, 75Ohms terminated
Tri-level sync: � 0.3Vp-p
Bi-level sync: 0.3Vp-p
PB/PR : �0.35Vp-p �2dB positive, 75Ohms

HDTV (GBR): BNC
G with Sync: 1Vp-p �2dB, 75Ohms terminated
Tri-level sync: � 0.3Vp-p
Bi-level sync: 0.3Vp-p
B/R : 0.7Vp-p �2dB positive, 75Ohms terminated

My specific questions are:

Is the Denon AVR4802 capable of correctly handling ALL of the above with its component inputs? Should I bother to learn what these specs mean or if they have any impact on anything in my system? What setting do I choose when using your run-of-the-mill HDTV signal: HDTV (Y/Pb/Pr) -or- HDTV (GBR)?? Why does my Sony reference the same physical RGB BNC-type inputs as: R and Cr/R-Y/Pr, G and Y, B and Cb/B-Y/Pb?

I'll send you guys a bottle of Jack Daniels and one of the best CDs you probably never heard if you guys can answer those last two questions!

A HDTV needs at least 150 MHz of bandwidth in the receiver to be passed on to your TV or projector without signal loss. The Anthem AVM-20 that we just reviewed has a bandwidth pretty close to that (120 MHz), but mass market receivers generally don't come anywhere near that (40 MHz typical). So, for your Denon, you should consider going direct to the projector, or get a high-end video switcher.

Choose the setting that matches the output of your HDTV decoder (Set Top Box or Satellite Receiver). If your HDTV decoder outputs either standard, I would suggest RGB, as this involves one less conversion.

The jacks are labeled indicating they accept multiple standards. When you group them this way, they make sense:

R/G/B (RGB (HV)) VGA Style Input
Pr/Y/Pb (Analog Component Video)
Cr/Y/Cb (Digital Component Video)
R-Y/Y/B-Y (Another way to name Component Video)

� Copyright 2002 Secrets of Home Theater & High Fidelity
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