Hello
If you can get a 10db decrease in noise for less than $20's in part expenses it's well spent. Even if don't have a noise issue it doesn't hurt the system overall.
Rob 🙂
So the general consensus seems to be that resistors aren’t going to have a deleterious effect and might even improve the SNR. There does though seem to be some debate about whether its better to put them on the input of your amp (assuming an active crossover) or put them on the input to the tweeter.
If your amp doesn't have a gain control you can add input resisters to pad the amp. The compression driver will need to be padded to match woofer/midrange. Resistors here will reduce overall system noise in the CD's bandwidth.
My amps have gain controls so I lower the unput sensitivity as well as a passive resistor pad on the CD as part of my overall system gain structure. This is in my analog active 4 way system.
Rob 🙂
Maybe that happens when adding a resistor to an existing crossover, to avoid response problems however when you measure and have a response target in mind, you can use whatever works.
The exception would be with regard to distortion, which some attend to and others don't worry about. In this case the source impedance is a factor.
Let’s say your tweeter is 6dB more sensitive than you mids / woofers. If you either, use an amp on the tweeter that innately has 6dB less gain than your other amps, or if all the amps have the same gain but you pad down the tweeter amp by 6dB, then why would you also need to pad down the tweeter ? What am I missing?
It depends for example typically it can be quite a bit more than 6dB Look at the rated 111 dB in the spec and the actual mounted to the 2380. It's about 115 dB. Now you are going to have to apply EQ to flatten the response and depending on how that works out you can still have more than 6dB to account for to level match the drivers.
Looking at the graph mounted on the 2380 you would target the 100dB line if you were just using the CD and no added tweeter as an example, Using a tweeter you could loose less level and cross at say 7K or so. Using a tweeter you obviously are going to require a lot more padding.
With my set-up I applied the EQ added a pad and still needed to trim off some level. My gain structure set for best S/N so unity in the active crossovers on the midrange and CD and over all EQ.
The driver that determines the overall sensitivity are my woofers at 98 dB It's an all active system so you have a lot of flexibility with the various gain stages
If you don't need both don't use both. That said I would always use the pad on the CD first and amps as a fallback.
https://www.lansingheritage.org/html/jbl/specs/pro-comp/2450.htm
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Padding on the line level (before the amp) doesn't reduce amp noise but padding on the speaker level does reduce all noise (including amp noise) coming from the electronics. Of course you need higher Wattage resistors for speaker level padding.
Padding the CD even gives some protection. Unless we’re talking about an integrated system, as in: amps in speakers, I’d always use that solution. With discrete components someone will err sometime somewhere.