Please help v/confused!

 

Mathyou
Unregistered guest
OK

I'm about to buy the Cambridge Audio Azur 640a. I have a MS308 sub to connect to it and am not sure of the best way. I know the 'daisy chain' system is one way, amp-sub, sub-speakers.

The 640 also has a pre-amp out, which the bloke in richer-sounds says can also be used to power the sub. But he said that I would only need to take a line from either the left or right of the pre-amp on the amp to either the left or right on the sub inputs.

I tried to explain to him my concern that this would mean that all the sub level frequencies that are in the channel not being use would be use would be lost. He wasn't having any of it and said it would be fine! Is this true? Surely it can't be right?

So the only thing I can think of is that I should use 2 sub phono cables and use both left and right outs and send them to the left and right (which my sub happens to have) of the sub.

I've never heard of this being done so just wanted to ask everyone here if I'm way off base or not? Please help!!!

Kind regards,

Matt
 

J. Vigne
Unregistered guest


The low bass frequencies that would be handled by the sub are mixed into mono. If you hear the bass apparently coming more from one side or the other, what you are hearing is the upper harmonics of the bass note. Beneath 125Hz, bass is increasingly non directional in nature due to the size of the wave front for a low bass note. Spreading the bass over both channels is a hold over from the days of vinyl. In the digital recording format it is still done to give more dynamic range and even power distribution to the low bass which are the most dificult frequencies to deal with in many ways. If you prefer to connect both channels you can certainly do that. Possibly the bloke was trying to save you the cost of a second cable.


 

Silver Member
Username: Varney

BirminghamEngland, UK

Post Number: 183
Registered: Sep-04
So where exactly does a sub connect to on the amp? Does one need a special amp, which is geared to take a sub?
 

J. Vigne
Unregistered guest

Who's that question directed to, Varney?


 

Bronze Member
Username: Ca_convert

CardiffUK

Post Number: 24
Registered: Jan-05
My question is why even use a sub? if you need a sub, why bother buying an amp of the 640's ability..?? Save yourself some cash you won't hear any different..
 

Silver Member
Username: Frank_abela

Berkshire UK

Post Number: 280
Registered: Sep-04
Another way of solving this problem is to use the high level input of the Sub. Most subs have two types of input - Low level and High Level. The Line level is Low-level. The High Level input of the sub connects three wires to the speaker terminals of the amplifier - one ground (either of the black terminals), and two positives one for the left positive speaker connection and one for the right positive speaker connection.

When you set up the sub, you change its volume and frequency values to integrate subtly with your speakers. Although the sub receives a full-frequency signal, it'll filter out frequencies above the value you set at setup time.

A sub can be useful if you're using bass limited speakers, but also if you're using full-range speakers. Most full-range speakers don't go below 50hz. Many higher-end full-range speakers don't go below 35hz. If you use the sub to fill in below this, then you will get an extended frequency response even further down. A good sub can go down to 18hz - a really good one can go down to 12hz. If properly setup, you will hear a difference, and bizarrely the difference won't just be in the bass! When setup correctly, subs seem to open up the midrange and treble lending more air to the proceedings. I don't know why this is, but it's something I've observed on many occasions.

Regards,
Frank.
 

Bronze Member
Username: James_the_god

Doncaster, South Yorkshire England

Post Number: 17
Registered: Jan-05
No matter how much you're willing to spend on a sub, there's no point in investing hundreds on one that could go deeper than 18hz because you simply can't hear anything that low. Plus no songs have the frequency that low unless ure driving around town in a Black BMW with 15 inch super woofers and extra subs installed everywhere.
Mathyou, your MS308 is pretty much perfect for a small subwoofer (but still big) and good for getting that extra 25-35 hz for some music etc and i know that sub can handle 35hz-stick with it, but im afraid i can't give you any help on the daisy chain connection thing!

James
 

Bronze Member
Username: Ca_convert

CardiffUK

Post Number: 35
Registered: Jan-05
The average (sic) human ear cannot hear much below 35-40Hz. Below this is feel rather than hear, but arguably ULF will generate harmonics perhaps even within the human body etc that replicates that sound. The Low E on a bass guitar is approx 100 Hz (go on someone tell me Im wrong - I'm extrapolating from A on a a treble clef at 440Hz).

My point is that most cheap subs (less than £500-£600) are more likely to "slow" the sound down, since they are incapable of maintaining the rhythmic tempo of the music, either through inferior design, or lack of amplifier control.
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