Your enclosures look simply stunning with that Teak veneer. Your supplier did a good selection for you, and your work applying it is spot on. I'm loving this process. Thanks for keeping us in the loop on your project.A couple more shots of the veneer, this was after the second coat, the flash really shows contrast between light and dark that the eye does not. My phone still does not do it justice, it almost glows.
The seams and grain continuity really turned out better than I hoped. This was my first "real" veneer project.
I was wondering when we would hear from you again. The speakers look great. Thanks for the update. Keep us informed as you dial in the crossover frequencies.
Sure would be nice to have an active crossover to use to immediately dial in the correct xover frequencies, then all you'd need to do is build the appropriate passive to match those on the active.
GeeDeeEmm
I will never claim to have everything figured out, but I have researched this to death and have a game plan. That game plan will work until I get hit in the face, then I will adapt.
The reasoning behind separating the low from the mid and highs, each with 4 ohm loads is so that the speakers can either be run off a single 8 ohm amp or split into two 4 ohm loads for two amps is so that down the road whomever ends up with these speakers has the option to run it with a single amp or multiple amps. Two 8 ohm speakers in parallel will present 4 ohms to the amp. The 4 ohm low and 4 ohm mid/high in series will present 8 ohms to the amp, thus enabling a conventional 8 ohm amp to play the speaker without fear of damage to the amp. I have to change the binding posts so that when the bridges are in place it runs the speakers in series instead of parallel.
Three 8 ohm speakers in parallel will present 2.7 ohms to the amp, dangerous to most amps.
https://geoffthegreygeek.com/calculator-speakers-in-parallel/
The crossover isolates the drivers in such a way that the amp only see a single driver. So, three 8 ohm drivers (low, mid, high), results in an 8 ohm speaker system.
gdmoore28 raised a good point about determining speaker impedance.
Speaker impedance is not a single, fixed value. Speaker impedance will vary over the speaker's frequency range. The impedance of three drivers, each operating over a different frequency band, are not combined as described in your link when determining the total speaker impedance. Calculating impedance for a speaker of multiple drivers is much more complicated and depends upon the specific frequency of interest and how the crossover is wired.
This I understand, and there are many other things to be learned.
The link you provided is for speakers, not for individual drivers that are connected to a crossover where only one driver operates at a time depending upon the frequency. That is, only the woofer is being driven at bass frequencies. At higher frequencies, the woofer can be considered to have a very high impedance. But that is when the mid-range driver kicks in. For the frequency range of the mid, the amp only sees the impedance for the mid-range driver and its portion of the crossover circuit. And a simple first order filter for a tweeter has a capacitor in series with the tweeter. Below the crossover frequency of the impedance of the tweeter circuit increases to infinity at dc (a capacitor blocks dc). As the frequency increases to the crossover frequency for the tweeter, the impedance seen by the amp for the tweeter will decrease to somewhere around the nominal impedance for the tweeter driver.
Agreed, somehow I missed that he was referencing complete speakers and not individual drivers.
Also, depending upon how you wired in the L-pads, that will also affect the impedance. So, too, will any attenuating resistors in the crossover circuit.
L-pads are between the crossover and the driver.
See https://www.avforums.com/threads/ohms-problem-diy-speakers.1578046/#post-16226293 for another explanation of how an amp sees only one driver at a time for a 3-way speaker with passive crossover.
Thank You! The entire purpose with this project is to learn. Responses are in body of quote.
Do you have any idea how to do what I am trying to do, make the speaker safe for most amplifiers that expect to see an 8 ohm nominal load, or will it be a 4 ohm nominal load no matter what because the woofer is a 4 ohm? It won't matter with the active crossover but the goal was to have it so it could be used safely by any normal amplifier.
I pulled out my multi-meter and the woofer with the 100 hz LPF is giving 4.3 ohms on both the left and right, the mid/tweeter gives no ohm reading, no short but no actual measurement on any of the Ohms settings. The meter is not really meant for this, it is a Klein MM100 that I got when I was doing the electrical on the house and it has issues.