Recap Resistor question

[Slim-Shaddy]

I'm FINALLY going to recap my main speakers, and I was wondering while I'm in there, should I do the resistors too? Also, what would happen if I changed the value of one of the resistors? The biggest complaint I have about the speakers is the fact that they are a bit weak on bass. There is a 5 ohm resistor going to the woofer. Would I get more bass without muddying the sound by putting a 4 or 3 ohm resistor in there instead?

[BrianT]

I'm FINALLY going to recap my main speakers, and I was wondering while I'm in there, should I do the resistors too? Also, what would happen if I changed the value of one of the resistors? The biggest complaint I have about the speakers is the fact that they are a bit weak on bass. There is a 5 ohm resistor going to the woofer. Would I get more bass without muddying the sound by putting a 4 or 3 ohm resistor in there instead?

Sorry I personally cannot help you.

But as Bob Caver say's TRY IT AND FIND OUT
and then let us all know

Brian

[rgpit]

Changing the resistor value may also change the xover frequency.

[Slim-Shaddy]

http://www.audiokarma.org/forums/attachment.php?attachmentid=249521&d=1294770546

here's the schematic...

[SunnyDaze]

I'm not an AK member so I can't view the schematic, but, I'm with Ron. Changing the value of a resistor can change the crossover parameters.

[Slim-Shaddy]

I think it depends on where the resistor is placed... that's where I get confused

[Slim-Shaddy]

I'm not sure how to attach a PDF file... we'll try this

[OldiesButGoodies]

changing that resistor would change the transfer function of the x-over (as sunny wrote),  but you may like the result.  So try it, specially if the change will be subtle (like 5 to 4ohms or even 3).  If it sounds god, that is all that matters.  Keep the old resistor in case you wish to revert.

[Slim-Shaddy]

Thank OBG. I may try it out. I just don't want to create a boost or gap in the FR between the woofer and low mid.

[schwarcw]

Hey Ed!

Have you ever tried to do a frequency sweep of your listening room with some test tones and a SPL meter?  You may have some nodes in your room that are either contributing factors or, the root problem for lacking a little bass.  This is a very common problem.  Your speakers, electronics, etc. may not be the issue.

[Slim-Shaddy]

Carl,
I've thought about it, but have never done it. I have an SPL meter (granted it's a cheapy from the Rat Shack), but no test tone generator. I'm going to recap regardless... The speakers are 30 years old, so it's past due. Since resistors are cheap, I'll probably replace them too while I have the board out. If it turns out that the room is the issue, is it resolved by moving furniture and adding sound absorption materials, or would I have to do some EQing?

[SunnyDaze]

The absolute foremost resource on those speakers is still alive and kicking. Email Roger Russell.

The truth of the matter is, in any circuit, when you change one parameter, all other parameters are effected in one way or another. See Mesh Analysis: http://en.wikipedia.org/wiki/Mesh_analysis

Changing the value of your resistor up or down an Ohm would have only a minor effect on the overall function of the crossover, but, I don't think that it would give you any more bass. It would slightly alter crossover points as well as change the overall impedance of the system, albeit most likely not very significantly by going up or down one Ohm. Assuming that the speakers remain in their current position, more bass would come from changing the T/S parameters of the low frequency drivers or changing the volume or configuration of the boxes.

If you REALLY want to know how much each of those values would change in the crossover network, you can build your system of linear equations using Mesh analysis. You can then throw your immense system of equations into MATLAB or LPSolve and find out.

Or you could just change them and see if you like how it sounds. 

[F1nut]

If you want to increase the bass response you should upgrade the inductors and leave the resistor values as is.

As for changing the resistors while in there, do it. I suggest using Mills 12 watt where the values permit.

[SunnyDaze]

Would upping the inductance of one inductor in a circuit have some side effects other than serving to increase bass output such as changing the frequency at which the signal is being filtered?

[F1nut]

You're not upping the inductance, you want the values to remain the same. You would replace the stock inductors with higher quality air core versions. Solen and Janzten are excellent choices. Since the gauge and DCR values are not noted, you'd need to have the stock inductors tested.