Thanks for your comments.
As you suggested I might need more amps
or different amps as others suggested.
Gathering all the advices, I will have experiment a lot
and think a lot about the changes.
Thanks for your advice and encouragment.
You are right. Measurement will help a lot and should be
the beginning of the project.
I checked that the harshness is not from mids.
It is more like prominent treble rather than noise or distortion.
Thanks for the Yamaha NS-10M trick information.
I will try this method can help.
By the way, the above tweeter is sensitivity 88.94dB.
Can I use it with changes only in tweeter crossover?
I hope to avoid the situation in which I have to change
the midrange and/or bass crossover to reduce the gains.
This was one of my original question in this thread.
What sensitivity is ok? what DCR is ok? something like that.
If you measure your tweeter, you will know what sensitivity it is, and therefore what is needed..
In theory, it won't work, if the speaker is actually 93dB.
The RST28f looks like a good one to try. If you can set it in place, cover the gap around the perimeter with painters tape.
The tweeter impedance doesn't really matter.
In theory, it won't work, if the speaker is actually 93dB.
The RST28f looks like a good one to try. If you can set it in place, cover the gap around the perimeter with painters tape.
The tweeter impedance doesn't really matter.
Last edited:
This would bring you close to a complete overhaul in which case you’d have to wonder other speakers wouldn’t be a better idea.
If the output transformer is inside the feedback loop, the level variations due to speaker impedance changes should be less of a concern.
It’s not that hard. You only have to measure mid and high range. Install REW and read the manual to get acquainted with the basics of performing a measurement. Connect your PC to the preamp and hook up the mike. Set gain on the preamp low. Run REW and see if things are working. A noise signal and a fast sweep are safer than a slow sweep, as the latter always starts at frequencies you won’t hear and you will be inclined to turn the volume way up.
You should hear the measurement signal and see that the microphone picks it up. Adjust the volume to a moderate level. Place the microphone on a stand or boom and position it at about 0,8 to 1m from the speaker, at tweeter height. Or, if you prefer, at listening height. Do test measurements. If REW is OK with levels, perform the measurement. If you like, post the impulse response here, so we can assist with interpreting the result.
You may go into information overload. Best to go back to basics and keep the speaker as stock as possible or could end up in tears.
Borrow a different amplifier with tone controls to see if it makes a difference.
The easiest is to increase the 2R7 resistor to increase the attenuation. Another easy method is leave the crossover as is but add a 15R resistor parallel to the tweeter after C2. This will give some attenuation and help dampen the tweeter.
Other thing to consider as well is the source, cables and room. I hope you find a good outcome as they look like a great speaker.
Borrow a different amplifier with tone controls to see if it makes a difference.
The easiest is to increase the 2R7 resistor to increase the attenuation. Another easy method is leave the crossover as is but add a 15R resistor parallel to the tweeter after C2. This will give some attenuation and help dampen the tweeter.
Other thing to consider as well is the source, cables and room. I hope you find a good outcome as they look like a great speaker.
Third option: Improve the compatibility of your chosen amp and speakers. This could be achieved by an impedance correction in parallel to the speaker. Maybe the aforementioned RC circuit is already enough. Maybe not. Measurements and some learnig may be needed.
Regards
Charles
This will change the crossover frequency. And the crossover is of the third order and very sensitive to the change of impedance. If the tweeter is going to be attenuated there, then the L pad must go to maintain as much as the same impedance as before. On the other hand, a larger resistor in front of the filter will not change the cutoff frequency, but the tweeter attenuation will increase the response gap between tweeter and mid. That's why I said a crossover revision would be needed.
As a reference, here are the technical and owner's manuals + spec-sheet.
Crossover frequencies are 380 and 3.000Hz
Crossover frequencies are 380 and 3.000Hz
If the sensitivity of the mids is actually above 93 dB
If the specs account for peaks or trying for best published
numbers. Which is likely.
It would be minimal to no padding needed for the tweeters
Luckily the documentation is good from the pdf posted in post #91
The mids are already padded very slightly. So the factory crossover
is already padded and has component locations to fine tune any padding
needed.
Look as if one mid is crossed lower , which is good for vertical.
It could be somewhat not as painful to fix the high Q on the high pass.
and change the lowpass to blend with, new tweeter added.
Least it is not a complete shot in the dark, no reverse engineering is needed
the documentation is good.
Last edited:
Yes, you are right.
Actually, I found it was already in the morning yesterday
while I read the recommendations and advices and hence
I had to go for work without sleep. I was reading all the
advices repeatedly several times because I found them
quite instructive to me and could understand many of
them at my first reading.
With time, I will try many thing one by one.
But, I will try with simple and basic things first keeping
your advices in mine.
I am generally of patient nature. So, I usually change
just a little bit and then hear the sound for weeks or
months to determine the results.
From this weekend, I will first study how I can measure
with the mic and will then try to make very slight tweak
with the crossover by increasing the value of 2.7ohm
resistor. I also think that might something I can do first.
I agree that room and cable are also important issues
as well as the section of tubes. In particular, I always feel
that analog cables play important role particularly in
the high frequency region. So, I will constantly think
about this issue.
I see.
But, as you and others advised, I will first learn
the measurement techniques from this weekend.
I will also install the REW software you mentioned.
After that I will reread what you advised to tweak
the tweeter crossover. After the experiment,
I am going to decide whether to go for new tweeters.
At this stage I will consider RST28F.
the F response of the BW is really unimpressing.
The designs from diy audio magazines like hobby hifi or klang und ton look usually much better(!)
I am pretty sure that linearizing with dsp on axis will make the tweets sound as they should!
They seem however to be 2 db too loud.
The designs from diy audio magazines like hobby hifi or klang und ton look usually much better(!)
I am pretty sure that linearizing with dsp on axis will make the tweets sound as they should!
They seem however to be 2 db too loud.
People here gave me a lot of instructive comments.
I am reading them multiple times to understand
and memorize. Since I cannot try everything at once,
I will try learn and test one by one with time.
I will begin with speaker measurement from this weekend.
Your above explanations are very helpful in understanding
the overall procedures. Thanks a lot for kindly explanations.
Also, regarding feedback loop and the frequency response
issue, I am relieved to hear that.
There is no bad design of crossovers only with B&W, but also with others. It's an enigma to me, they have all the necessary equipment, they have engineers, and they throw out errors again. Mainly mainly deal with exterior design that attracts the audience, less with being technically correct. What madness. 😁
I see. I will take note of your advices regarding EQ.
Regarding acoustic measurements, I think you are 100% right.
To be frank, I was so daunted by the concept of measuring
speaker sound 'at home' that I was very reluctant to try.
But, I also know that it inevitable make a try for my case.
So, I will try to learn how to measure but always with
your caution in mind.
It is difficult to measure large speakers, but you are primarily interested in the response of medium and high frequencies, and that part is not large. The tweeter and two mid drivers are relatively close. You can measure at 1m in the axis of the tweeter, at 1.5m, at the listening position, out of axis, etc. You have gating in the measurement to turn off everything below 200-300Hz to make measurement more realistic above 1kHz, etc. I say again, download Holmy Impulse, it's the easiest for the first time. REW is much more complicated because there are many options.
Thanks for your comments.
I hope so.
I guess there are some reasons for somewhat
less than ideal measurement results. Different
measurement setup might have resulted in
different results.
However, I feel that the measurement results
seems to support what I am actually hearing.
I owned these speakers for very long time.
Over decades, there were people saying
similar things as I. They also thought treble
sounds a little loud.