Help the uninformed

[arthurs]

Could someone give me a simple, layman's explanation for the following and reccomend settings?

Crossover

High Pass

Low Pass

Peak Limiter

LFE Level

My system is as follows:

B&K 7250

B&K Ref30

RF-7 fronts

RC-7

RSW-15

RB5II surrounds

MonsterPower 2600

Samsung 43" DLP

Theater is in a good size and acoustically solid room.

I like pronounced bass delivery in both movies and music, and am wondering how the settings of any of the above affect my sound.

Thanks for any help

[shoe11]

Looks like someone had some fun with a Tweeter card!

I'll take a shot at this one. You'll notice on your sub that you have a switch for low pass or LFE. Use LFE for movies, and a recommended setting is 80mhz within the receiver for the crossover. Use the low pass for music. For the low pass crossover with the RF-7's, I keep the RSW-15 set at the minimum 40hz. Given that the 7's go very low by themselves, you'll really want to play around with your settings to find the bass output which makes you most happy. High pass shouldn't come into play with your setup and the only thing I've heard regarding SPL is that in HT mode you should calibrate each speaker to the same volume level. Perhaps the more HT oriented people on here can expand on that one for you.

~shoe

[WMcD]

The general problem is that tweeters can only reproduce high frequency music. Woofers can only reproduce the low frequencies. Also, it is best that they only be fed with the frequencies they reproduce.

Typically a speaker box (system) has connection directly from the amplifier, yet the box has a tweeter and woofer. So there has to be something in the box to divide up the input into high and low frequencies. In the old days it was called a "divider". The new name is "crossover".

The elementry set up we're talking about has two filters. One is a "high pass" which passes through only frequencies above, say, 2000 Hz. The output is connected to the tweeter.

The other is a low pass which only passes frequencies below 2000 Hz.

The frequency of the crossover, both the physical circuit, and the results, is 2000 Hz. This is where the signal input to the box crosses over from the woofer to the tweeter, as you go up in frequency. So you can see the term "divider" is very accurate too.

Our discussion so far assumes that the output of the amp is full range. Also it assumes, a bit, that the signal recorded on a CD or LP is wideband and has both bass and treble. There may well be a left and right channel recorded, but that is why there are two boxes, left and right.

In modern DVD's (And SACD and DVD-A) there are actually six channels recorded. Left, Center, Right, Left surround, Right surround, and low frequency effects. It is 5.1 channel recording with the 0.1 being the LFE. It gets a 0.1 because it is not full range, while the 5 other's are.

Now you have to be very careful. Many home theater speaker set ups are called 5.1 also. But this refers to the speakers only. The subwoofer is indeed the 0.1. Now you'd think the channels recorded and the speakers, correspond to each other. But not so. In fact the early "Dolby" surround HT receivers and multispeaker systems were fed off of what was actually just a two channel source (two tracks on VHS tape) and then did some amount of processing to divide it up to synthecize 5.1 channels.

An HT receiver is much more sophisticated that just a "direct feed through" from the recording to the speakers. More below.

Going back to the speakers. Very typically the center and surround speakers are small. Sometimes the L and R. Why make the 5 speakers with good bass response if the bass can be sent to the subwoofer.

Therefore, regardless of the input to the HT receiver, it is going to divide up the frequencies so that all the bass below 70 Hz (typically) is sent to the sub. At least that is one setting in the HT receiver amp. The rest above 70 Hz go to the appropropriate speaker L,C,R,LS, RS.

There are all sorts of settings on menus. For example, if you tell the HT receiver there is no sub, it should send low frequencies to any of the 5 speakers which are, on another menu, set to "large". Setting to "large" says it can reproduce bass. That includes bass from a regular old CD, or the LFE.

On the other hand, if you do have a sub, and the main L R speakers are set to small, the sub should get both the LFE on the DVD, and also the bass recorded in the 5 other channels on the DVD.

The above may require close reading. The industry has really allowed some confusion because we have 5.1 recordings on DVD, and there are 5.1 speaker systems.

Limiting circuits are sort of like an automatic volume control. When the signal gets too strong, it turns down the volume, automatically. There is much art to how fast this thing should turn down the volume, and then, if the peak subsides, how quickly it turns it back up.

You may see this in settings for "night time" on the HT receiver. When the bad guy is blown up, the circuit turns down the volume so the wife and kids are not awakened. Or maybe that is dad when the kids are watching.

Perhaps some others can give you specific settings which are appropriate to your HT and speakers.

Gil