Resistors vs.peltz Autoformer- Differences

Resistor.... Q of the woofer and of the system will change.... QES and QTS will raise.  The woofer will want a larger box or want to head towards a sealed box rather than ported.  I've never really like what resistors did to the sound of the bass.... Of course,  it does raise the overall system impedance, but there is no free lunch.  
Be aware that depending on other criteria,  it is possible that you could get a sucked out mid range or a rolled off top end.... But,  its an inexpensive and easy experiment.  
I hope this helps,
Tim

Aside from the load impedance, wouldn’t adding a resistor in series with speaker driver affect the high frequency response of the driver, particularly in case of a single driver or a tweeter?

@kalali

Yes, adding a resistor in series will dramatically change the output impedance that is presented to the speaker. That can and in most cases will have major tonal consequences in various parts of the spectrum, depending in part on how the speaker’s impedance varies as a function of frequency.

Best regards,
-- Al

Thanks Almarg, et al.
@millercarbon,
Yes, I agree, getting the right equipment is the best approach. I was curious as to how either method worked, especially with regard to sound reproduction.
Given that Zu has signed off on the resistors, I would imagine they find any tonal differences to not be significant.

B

Given that Zu has signed off on the resistors, I would imagine they find any tonal differences to not be significant.

The only way I could see that working, is if the speaker was purposely over damped in it’s design, and all you do with the resistors is to ruin the damping factor (output impedance) of the amp so then bass is then becomes correctly damped (to suit the room maybe)? Whatever it is, it’s a wank, so are Autoformers, just get the right speaker or amp to do the job properly. 

Cheers George

I’m not sure if everyone is keeping in mind the distinction between series connection of a resistor and the parallel connection that is being suggested by Zu for some of their high impedance speakers. The effects of the two kinds of connections are of course completely different.

For one thing, the parallel connection being suggested by Zu will actually improve the damping factor, at least a little bit, rather than degrading it. The reason for that is that with a resistor connected across the speaker terrminals the impedance "looking back" from the speaker will be the parallel combination of that resistance and the output impedance of the amp. And the impedance of that parallel combination will be lower than the output impedance of the amp.

Also, Bob, I think you meant to address George in your previous post, not Millercarbon who has not participated in this thread thus far.  An understandable mistake, though, given the latter's posting frequency :-)

Best regards,
-- Al