Alright, I will try to give you all the info I have on this issue and describe it to my best ability. Because it has been a mystery to @jReave and myself.
I have taken the last four months or so to build my speakers after designing for a few months. Pictures attached below.
I am now onto the testing phase for the drivers and everything was looking good up until I was testing the tweeters. Essentially, the FR would start ramping up +5dB around 4kHz, which is nothing like the data sheet.
The tweeters are the:
Dayton Audio RST28F-4 1-1/8" Reference Series Fabric Dome Tweeter 4 Ohm
Even the impedance testings where all over the place.
It was deemed that I got a bad batch of the tweeters. I had Parts Express test a batch form their inventory and they got good results. So they sent me those new ones to use now.
So, now I put one of the new tweeters in my tower and have now gotten a slightly better FR, yet similar results to what I got before. Picture attached.
The green trace is the new tweeters I just measured. The blue trace is the measurements from the bad batch tweeters. The red trace is the .frd file I got from Parts Express' tests.
Essentially, there has to be something wrong with my testing set up. So, let me lay down the setup I have now. Parts Express didnt even have anything to say about it.
- I have the speakers off the ground on a small table, they lead to a Denon DRA-297 receiver with the "Pure Direct" button on, which will bypass any internal EQ.
- I then have a DBX RTA measurement mic that leads into my Focusrite Scarlett 2i2 Gen2. The mic also has a calibration file I use on the software.
- I am using the Room EQ Wizard software on my Mac Book Pro and have set up all the calibration SPL and sound card stuff.
- I am testing in my basement where the walls are about 7-8 feet away, with blankets/foam mattresses/quilts on the walls to dampen the room further. I also gate my responses by 3ms to get rid of any wall reflections.
- I have checked for any internal EQ on my Mac and there is nothing.
- I have also measured a different Dayton tweeter I have laying around and got very close results to the spec sheet.
So, why are these tweeters being a mystery?
Any ideas would be greatly appreciated and if you need any more clarity on something. Please let me know!
I have taken the last four months or so to build my speakers after designing for a few months. Pictures attached below.
I am now onto the testing phase for the drivers and everything was looking good up until I was testing the tweeters. Essentially, the FR would start ramping up +5dB around 4kHz, which is nothing like the data sheet.
The tweeters are the:
Dayton Audio RST28F-4 1-1/8" Reference Series Fabric Dome Tweeter 4 Ohm
Even the impedance testings where all over the place.
It was deemed that I got a bad batch of the tweeters. I had Parts Express test a batch form their inventory and they got good results. So they sent me those new ones to use now.
So, now I put one of the new tweeters in my tower and have now gotten a slightly better FR, yet similar results to what I got before. Picture attached.
The green trace is the new tweeters I just measured. The blue trace is the measurements from the bad batch tweeters. The red trace is the .frd file I got from Parts Express' tests.
Essentially, there has to be something wrong with my testing set up. So, let me lay down the setup I have now. Parts Express didnt even have anything to say about it.
- I have the speakers off the ground on a small table, they lead to a Denon DRA-297 receiver with the "Pure Direct" button on, which will bypass any internal EQ.
- I then have a DBX RTA measurement mic that leads into my Focusrite Scarlett 2i2 Gen2. The mic also has a calibration file I use on the software.
- I am using the Room EQ Wizard software on my Mac Book Pro and have set up all the calibration SPL and sound card stuff.
- I am testing in my basement where the walls are about 7-8 feet away, with blankets/foam mattresses/quilts on the walls to dampen the room further. I also gate my responses by 3ms to get rid of any wall reflections.
- I have checked for any internal EQ on my Mac and there is nothing.
- I have also measured a different Dayton tweeter I have laying around and got very close results to the spec sheet.
So, why are these tweeters being a mystery?
Any ideas would be greatly appreciated and if you need any more clarity on something. Please let me know!
