Q&A # 132 - August 14, 1999

Staff

Q I haven't made any extensive testing whether cables make a big difference or not so I'm in neither camp yet. I purchased the Magnepan 3.6 and just received the speakers this Saturday. They sound awesome by the way. I was hooking up the crossover box to the speakers and noticed I had to use 4 little nodes to attach the box. The diameter of those little nodes appears to be 1/10" and appears to be made from stainless steel or silver, I couldn't quite tell, they were so small. The speaker wires are then attached to the crossover box. If I'm using megabuck speaker wire and the signal crosses those nodes, does the signal default to the lowest common denominator in the system? Also the speakers have fuses for the woofer panel and the ribbons, so I'm also assuming the signal passes through that as well.

A I doubt that the nodes are silver. They are probably nickel plated. As to the various pathways, the sound will be affected by each item in the path, but it isn't "choked up" by the weakest link. As long as the high performance cables are, say, 95% of the path, and the inexpensive connections are short, the sound will have only a marginal degradation by the inexpensive section. The same goes for the fuses. They are not exactly high performance speaker path, to say the least, but they are only about an inch in length, so, again, they will cause just a slight effect.

Q I am currently using the DSP-A1, equipped with Cinema EQ and Center EQ menu parameters. I have also just upgraded my center channel speaker to Polk's top-of-the-line CS1000P (with built-in subwoofers). My goal is to finally have a center channel that does not sound boxy in full range (or limited range for that matter). I have heard that the Center EQ is supposed to help with bass loading on RPTV screens. However, there is absolutely no guidance on how one would go about compensating for this effect. The manual says to adjust Center EQ and Cinema EQ together. However, the manual fails miserably in describing how or why one would do this. Can you shed any light on this odd subject? I am sure most receivers have similar features, probably just called something else. If you can give some general guidance on how to adjust these two parameters, and what the adjustments do, I would be extremely grateful. Withnot knowing, I fear I am not getting the most out of my system.

A The DSP-A1 Center GEQ is a Graphic EQualizer for the center channel only. It lets you modify the response in five different frequency bands to compensate for the effects of the TV screen in the 100 Hz and 300 Hz regions, but also to compensate for nasality in the 1 kHz region, harshness in the 3 kHz region, and tizziness in the 10 kHz region. Cinema EQ is for balancing tonality among all the speakers, including the center, but it adjusts response at 1 kHz and above (16 bands to choose from), and does not have bands below 1 kHz to select. Because the GEQ has selections at 1 kHz, 3 kHz, and 10 kHz, its effects overlap those of the Cinema EQ, so that is why they suggest you adjust them together. What I did was adjust only the 100 Hz and 300 Hz bands of the center channel with the GEQ, and use the CInema EQ for adjusting everything else. I used a DTS music CD to make the adjustments, and focused on music that had voices (singing).

Q I am using an Adcom 545 amp (100w) and want to upgrade to 5 channel. Do I need to stay with Adcom in order to maintain timbre matching? Also how close in watts should the front three channels be to the rear channels?

A Amplifiers are pretty generic in tonality, so you can get any brand that suits you. What you do have to be concerned about is sensitivity and power. If the sensitivity and power for the front channels are higher than that for the rear, you will end up with a situation where the volume is much higher in the front, and you will have to use the channel volume controls to reduce it substantially in the front or increase it in the rear to maintain balance.

Q I am planning to upgrade my home A/V system. I currently have a newer mid-range Pioneer A/V receiver with AC-3 rated at 100WX5. I have been told that going to a high-current amp will make a significant improvement, even if it is rated at a lower wattage (say 70). Do you agree? My dilemma is this. I have a set of 4 Ohm AR-9 speakers I want to use as mains, 8 Ohm Cerwin-Vega D-3 surrounds and an 8 Ohm center. I also have a powered subwoofer. What are the ramifications of running 4 and 8 Ohm speakers in this system. I have to replace the 8" woofers in the D-3s anyway. (Believe it or not, someone actually stole just the woofers and left the rest of the cabinets intact.) Should I replace the 8 Ohm woofers with 4 Ohm? By the way, any tips on selecting replacement woofers?

A The term high-current usually refers to the ability of an amplifier to drive low impedance loads, such as 4 Ohm speakers. Using 4 Ohm speakers with receivers is generally not a good idea, because receivers don't have very big power supplies. However, in your situation, you will be using 4 Ohm speakers in just two of the channels. It would have been better to have them in the rear, where the signal is not so intense. You will need to adjust the front left/right volume control carefully, and it should be OK. As to the woofers, you should use 8 Ohm, not 4 Ohm since the originals were 8 Ohm. You might try getting in touch with Cerwin-Vega (http://www.cerwin.vega.com) about replacement drivers. Otherwise, use drivers from one of the many driver suppliers, such as Madisound (http://www.madisound.com/).

Q In the final Q&A for 20 July, the writer referred to using a budget DD/DTS receiver with 6 channel pre-outs, with the aim of connecting high quality outboard amps later. What happens, then, with DVD players such as the Philips DVD860 which includes 6 channel analog output for DD, DPL and stereo? If you want to use existing outboard amps with this DVD player, what is required as the control unit?

A If DVD players had master volume controls on them, you could connect their analog outputs to a five-channel outboard power amplifier and the subwoofer. Another alternative would be to use an outboard amplifier that has individual volume controls for each channel. There are several models of amplifiers that have such controls. However, this would prevent you from switching sources easily, which is one of the functions of preamplifiers. So, the best method is to connect the analog outputs of the DVD player to the analog inputs of the receiver (called pre-ins), and the pre-outs of the receiver to the outboard power amplifier. I suspect you may have confused the various pre-outs and pre-ins, as to their functions. If your receiver has DD and DTS decoding built-in, you just use the digital output from your DVD player to one of the digital inputs on the receiver, rather than using analog outputs from the DVD player to analog inputs on the receiver. But this does not affect the use of the pre-outs on the receiver, which can always be used with outboard power amplifiers.

Q I'm using a California Audio Lab Icon MkII CD player, and now I want to upgrade using a separate D/A converter. I have choices such as CAL's own GAMMA D/A, or MSB LINK DAC etc. My player presently uses Siltech's 4/56 as interconnects. I've heard a lot about MSB and even CAL's ALPHA DAC.  My player retails for $995 U.S. Based on my player and wire, which DAC would be a good upgrade to match my ICON MKII as a transport.

A Adding an outboard DAC to a player is not as simple as just buying a good DAC and connecting it. Unless the outboard DAC can synchronize its operation with the output from the transport, you could very well end up with worse sound, even if the DAC is a good one. So, proceed with caution. Only make the change if you are unhappy with your present sound. If you get an outboard DAC, I would suggest going with the CAL. This will increase your chances of a proper match. Be sure to use a good digital cable for the connection.

Q I'm using a Pioneer SPD07 DD & DPL decoder and there is a feature called Crossover where there are crossover points of 100 Hz, 150 Hz, and 200 Hz. The bass at my main speakers is down to 20 Hz, center 38 Hz, rear 40 Hz, and sub 18 Hz. I set all my speakers to LARGE. As such :

(1) which crossover point should I choose among the 3 given by my decoder?

(2) there is an LFE channel attenuation level of 10 dB then 0 dB, then off. The recommended is 10 dB, but it states that if this is chosen, the front 3 channels output is required for the subwoofer. What does this mean? At present I've chosen the 0 dB.

(3) When playing DD, one has to choose the subwoofer mode. The decoder provides NONE, MODE1 (Subwoofer output only), and MODE2 (subwoofer output + Left, Center, Right channel bass). Which is the correct choice and what does MODE2 mean? At present, I chose MODE1.

A The crossover settings mean the point at which you want signals to be sent to the subwoofer vs. the other channels. Setting your speakers to Large will cancel the effects of the crossover settings. If you set any particular speaker to Small, then the frequencies below the crossover setting will go to the subwoofer, and the frequencies above that setting will go to the speaker set to Small. Since you have all your speakers set to Large, don't worry about the crossover setting. But I would leave it on 100 Hz anyway. As to question 2, I have no idea. You have done the right thing in setting it to 0 dB. This will give you no alteration in what is coming from the DVD player. For MODE2, this sends the front left/center/right bass, along with whatever bass there is in the LFE to begin with, to the subwoofer. This would be used when you have small front speakers. Since your speakers have good bass response, your setting of MODE1 is the right one.

Q Presently I am using my DVD player (Toshiba SD-3109) to play audio CDs. I know that you have not reviewed this player, however, you did review the SD-2108. Well, the SD-3109, has HDCD for audio CDs. The SD-3109 can be purchased for $399. If I invest up to 2 to 3 times as much on a CD player ($800-$1200), would the quality of the music improve 2 to 3 times, or would the improvement be 10%, 25%,100% or somewhere in-between?

Additional Info:

Pre-amp/pro: B&K Ref20

Power amp: B&K 5000II (5x125)

Main speakers: B&W 602

Rear speakers: B&W 601

Center speaker: B&W: CC6

Sub: Velodyne VA-1012X

Nordost speaker cable

Straight Wire interconnect.

A The first DVD players were not very good at playing CDs. There are a few DVD players now that are pretty good, specifically the ones with dual lasers. However, they are close to $1,000 in price. The 3109 will be fine for DVDs, but you would be better off with a dedicated CD player or one of the dual laser DVD players to handle CDs.

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