HPM-100 Makeover
- Thread starter Wayne1
- Start date
Wayne1
Speaker Butcher
You are absolutely correct, dnewma04. The calibration was completely wrong on the RTA program. mea culpa
I was checking the response of the crossover and I kept getting the same graphs.:worried:
I'll remove those and re-do them later.
The crossover point on the stock is 3kHz. The new crossover is 1.5 kHz.
Sorry for the screw-up.
Not on my account, I hope.
There's no saying that what I got measuring them is "right," either. We certainly found similar and significant response anomalies in the same locations within the spectrum.
It's all good, and all instructive.... :yes:
Wayne1
Speaker Butcher
Zilch,
The calibration of TrueRTA was wildly off. I should have guessed something was wrong by that monstrous dip at 1kHz.
I have used TrueRTA for years to position speakers in rooms and adjust sub woofer EQ at the listening position.
This is the first time I have tried to use it to actually measure a speaker's performance. I also just upgraded to the latest version. I am sure there are little bugs I need to work around. I'm just sorry that I posted erroneous data.
dnewma04,
The "WayneLab" for measuring is my daughter's bedroom. While she is away at college I have turned it into speaker central. The Behringer ECM-8000 mike is on a boom and as close to level with the tweeter as I can manage. The mike is located 1 meter from the cabinet. The base of the cabinet is 22" off the floor. The tweeter is 1 meter off the floor. The speaker is "aimed" out the door to a large open area.
The mike is plugged into a M-Audio DMP3 pre-amp which also supplies the phantom power. The pre-amp goes into a Sound Blaster Audigy 2 USB. True RTA version 3.4.1 is what I have on the laptop.
The calibration of TrueRTA was wildly off. I should have guessed something was wrong by that monstrous dip at 1kHz.
I have used TrueRTA for years to position speakers in rooms and adjust sub woofer EQ at the listening position.
This is the first time I have tried to use it to actually measure a speaker's performance. I also just upgraded to the latest version. I am sure there are little bugs I need to work around. I'm just sorry that I posted erroneous data.
dnewma04,
The "WayneLab" for measuring is my daughter's bedroom. While she is away at college I have turned it into speaker central. The Behringer ECM-8000 mike is on a boom and as close to level with the tweeter as I can manage. The mike is located 1 meter from the cabinet. The base of the cabinet is 22" off the floor. The tweeter is 1 meter off the floor. The speaker is "aimed" out the door to a large open area.
The mike is plugged into a M-Audio DMP3 pre-amp which also supplies the phantom power. The pre-amp goes into a Sound Blaster Audigy 2 USB. True RTA version 3.4.1 is what I have on the laptop.
Wayne1
Speaker Butcher
Better RTA pictures
I spent some time working on measurements today.
Here are some better RTA pictures of the speakers that are a bit more accurate showing the differences that I heard last night.
Stock
Modded
Both
Low Frequency (mike was placed 1/4" from woofer)
Stock
Modded
Both
I spent some time working on measurements today.
Here are some better RTA pictures of the speakers that are a bit more accurate showing the differences that I heard last night.
Stock
Modded
Both
Low Frequency (mike was placed 1/4" from woofer)
Stock
Modded
Both
See the published factory curves on the back of the speakers.
HF should climb up ~8 dB above 1 kHz.
Set the L-pads to max and see if that happens. :yes:
What did you do to "fix" it?
What is your calibration standard?
Wayne1
Speaker Butcher
Zilch,
TrueRTA auto calibrates. You can have it calibrate for whatever soundcard you are using. It also has mike calibration files.
In my case, the power to the mike pre-amp came out. The computer "freaked" and lost calibration. I had to power re-cycle and re-calibrate for each test I wanted to run. Part of the problem using a consumer RTA.
I finally finished the second cabinet today. I first installed the No-Rez. I ran a quick WT3 sweep. with the stock crossover. I will post that tomorrow.
Gibsonian was correct in stating that the foil inductors had a greater effect on the WT3 response than the cabinet dampening.
I am just about finished with this project. It was fun.
Next up some Boston Acoustics Makeovers :beer:
TrueRTA auto calibrates. You can have it calibrate for whatever soundcard you are using. It also has mike calibration files.
In my case, the power to the mike pre-amp came out. The computer "freaked" and lost calibration. I had to power re-cycle and re-calibrate for each test I wanted to run. Part of the problem using a consumer RTA.
I finally finished the second cabinet today. I first installed the No-Rez. I ran a quick WT3 sweep. with the stock crossover. I will post that tomorrow.
Gibsonian was correct in stating that the foil inductors had a greater effect on the WT3 response than the cabinet dampening.
I am just about finished with this project. It was fun.
Next up some Boston Acoustics Makeovers :beer:
I am suggesting that your high-frequency measurements above 1 kHz may not be accurate; they are very different from my results measured RTA, MLS, and Sinusoidal, and they do not resemble the factory curves.
I would be very surprised to learn that HPM-100s can be dialed flat to less than 2 dB from 1 kHz to past 20 kHz.
Turn the L-pads to max and remeasure to verify that your RTA is responding in that range....
I would be very surprised to learn that HPM-100s can be dialed flat to less than 2 dB from 1 kHz to past 20 kHz.
Turn the L-pads to max and remeasure to verify that your RTA is responding in that range....
What is the measurement being done? Are you using steady state pink noise with mic at the listening position? 1m? Are you gating to get pseudo-anechoic?
Z, a steady state pink noise in room would probably drop down the high end a bit relatively speaking. Although if that were the case I'd expect more rolloff above 10 or 12kHz or so.
Ray
Z, a steady state pink noise in room would probably drop down the high end a bit relatively speaking. Although if that were the case I'd expect more rolloff above 10 or 12kHz or so.
Ray
Here are my 1/6 octave in-room RTA measurements:
Even though they were taken with bypassed L-pads, they approximate the factory curves well:
Complete findings:
http://www.audiokarma.org/forums/showthread.php?p=1801956#post1801956
Hi Wayne, I was disappointed to see this thread finish when you were so close to the end. The impedance/phase angles graph back on page 1 seemed to indicate your mods would present a more consistent load to valve amplifiers than the original crossover.
I'm not overly happy with the sound from my untouched mint HPM 100s and hope that this thread continues and you can respond to the last posts in this thread.
I'm not overly happy with the sound from my untouched mint HPM 100s and hope that this thread continues and you can respond to the last posts in this thread.