Finally a simple and transparent video explaining the confusion surrounding impedance - As someone getting into high end audio this element has been one of the hardest concepts to apply because of how manufacturers list impedance, but I never knew that until now!
What about a 4 ohm nominal impedance but drops down to 2 ohms at 90hz with just over -45° of electrical phase? Still fine on any old amplifier? Does output levels become an issue with low impedance dips with negative phase?
My impedance curve om my midbass shows 1 hump on 75 and one on 150. When i mesure frequency responce i also get gain in 75hz and 150hz. My goal is 75hz hump and then somewhat flat response upwards. I use a sub under75hz so dont worry about that. When i put a longer port in, the lower hump goes lower but the upper peak stays the same. I dont want the upper peak at all or get the upper peak lowered to 75 and the lower peak probably landing at 35 hz or so. To adjust the upper peak, do i have to adjust the size of my cabinet?
Hi. We don't really support DIY speker building, and without more information it would be difficult to give you a correct answer - but I will try to give you some pointers: The resonance frequency/port tuning of the speaker is basically the saddle between the two peaks. This resonance frequency is defined by the cabinet size as well as the port diameter and length. When you are increasing the length of the port, you are lowering the tuning frequency, moving the saddle downards. The peaks in the impedance response does not necessarily correlate with peaks in the frequency response, although it sounds like it does in your case. You would need to simulate the response to figure out which combination of box and port would work optimally, and depending on the driver you won't necessarily be able to reach your goal. But, your goal is the frequency response, not the impedance response. The impedance curve is the means to and end, not the end itself. In a ported cabinet you will have two peaks no matter what, but two peaks in impedance does not equal two peaks in frequency. If you have frequency bumps, that's what you need to solve. A sealed cabinet will have only one impedance bump, which will be defined by cabinet size (and stuffing). This may or may not work better in your scenario where you have a subwoofer. That is the art of speaker building - you don't really know before you try it, or at least simulate it.
Finally a simple and transparent video explaining the confusion surrounding impedance - As someone getting into high end audio this element has been one of the hardest concepts to apply because of how manufacturers list impedance, but I never knew that until now!
This was a fantastic video. Thanks for sharing.
Great video! I have the same model of amplifier (Yamaha A-S801?) featured in the presentation. Very happy with my Evoke 30’s. 🔊🔊
Interesting stuff on the impedance switch on the amplifiers..
What about a 4 ohm nominal impedance but drops down to 2 ohms at 90hz with just over -45° of electrical phase? Still fine on any old amplifier? Does output levels become an issue with low impedance dips with negative phase?
My impedance curve om my midbass shows 1 hump on 75 and one on 150. When i mesure frequency responce i also get gain in 75hz and 150hz. My goal is 75hz hump and then somewhat flat response upwards. I use a sub under75hz so dont worry about that.
When i put a longer port in, the lower hump goes lower but the upper peak stays the same. I dont want the upper peak at all or get the upper peak lowered to 75 and the lower peak probably landing at 35 hz or so. To adjust the upper peak, do i have to adjust the size of my cabinet?
Hi. We don't really support DIY speker building, and without more information it would be difficult to give you a correct answer - but I will try to give you some pointers: The resonance frequency/port tuning of the speaker is basically the saddle between the two peaks. This resonance frequency is defined by the cabinet size as well as the port diameter and length. When you are increasing the length of the port, you are lowering the tuning frequency, moving the saddle downards. The peaks in the impedance response does not necessarily correlate with peaks in the frequency response, although it sounds like it does in your case. You would need to simulate the response to figure out which combination of box and port would work optimally, and depending on the driver you won't necessarily be able to reach your goal. But, your goal is the frequency response, not the impedance response. The impedance curve is the means to and end, not the end itself. In a ported cabinet you will have two peaks no matter what, but two peaks in impedance does not equal two peaks in frequency. If you have frequency bumps, that's what you need to solve.
A sealed cabinet will have only one impedance bump, which will be defined by cabinet size (and stuffing). This may or may not work better in your scenario where you have a subwoofer. That is the art of speaker building - you don't really know before you try it, or at least simulate it.