Don't think that these are as problematic as you read on these forums. THe studies which tell you that these cchanges in the signals are audible are very controlled. Our ears are very forgiving when there is actual multi-tone music being played back.
I did a front loaded horn subwoofer that a few commented would have such massive group delay it would be horrendous. When they listened to it, a totally different story.
Now for midrange, if you are worried and you feed your speakers a signal via a computer you can use Rephase to make corrections. And there are a few stand alone DSP boxes that will accept the correction files as well.
My only guarded thoughts are to make comparisons be sure to do it blindfolded A/B/X type testing. It can be very humbling as to what you truly can hear, and what you believe that you hear.
Mark
The Hornresp Power Compression tool simply changes the driver voice coil dc resistance value Re to take into account the specified increase in voice coil temperature above 20 degrees Celsius (the resistance of the voice coil increases with temperature).
Hornresp does not care what value of Eg is being used. Input power is not a factor, only the voice coil temperature.
I changed the rear chamber volume to 0 and the schematic looks more similar to the one you showed me now.
VAS for tweeters -is it possible to measure that with a tiny weight and a tool such as Dayton DATS? I am considering buying one of those.
Yes you can calculate a tweeters Vas but you need a small sealed volume to put the tweeter against. This volume will cause a shift in the impedance and you can then calculate the Vas. So, basically a cup of know volume. Relatively small, maybe 50 to 100ml that seals perfectly to the front of the tweeters face plate. Do your Test as if it is against a sealed test enclosure.
Mark
I suggest you do "Watch" on top of page and go for none email notifications - you only have to visit the site once a day to keep track of active threads. As a bonus you will have a cleaner inbox in your mail
I did a lot of unsubscribe (by hitting Watch button and the immediately resubscribed by hitting the button again - choosing notification without email.
Happy up-2-date forum surfing!
//
Ah! Do you happen to know if Dayton DATS has that kind of calculator built into the software?
Well, nothing ventured, nothing gained. I just set it up as you suggest. Now I can only blame myself!I suggest you do "Watch" on top of page and go for none email notifications - you only have to visit the site once a day to keep track of active threads. As a bonus you will have a cleaner inbox in your mail
I did a lot of unsubscribe (by hitting Watch button and the immediately resubscribed by hitting the button again - choosing notification without email.
Happy up-2-date forum surfing!
//
Mark
It should have either a sealed box option or a mass loaded option. I do not use DATS. I use the system by Smith & Larson. But the measurement principles are the same. You are looking to create a shift in the impedance via a kknown method of either resistance to movement via a constriction of a known air volume in front of the diaphragm, or a known mass addition. Both methods end up creating the changes required.
Mark
With regards to back chamber volume...in the mid bass horn I proposed on previous page, hornresp suggested an optimal Vrc which was smaller than what would be required for the driver to fit into.
I adjusted the volume so the driver would fit into the chamber and this resulted in a "still ok" but less linear response.
One solution to maintain the small volume suggested by horn resp would be to design a shorter chamber with the magnet of the driver sticking out, but not sure this is a viable option.
As I write I also wonder if Vrc is the volume of the chamber + the volume of driver (cone + magnet).
So, if supposedly my driver (magnet + cone) occupies a volume of 1liter, a Vrc of 1 liter means I have to design an enclosure of 2 liters.
On such small volumes this makes a big difference.
I adjusted the volume so the driver would fit into the chamber and this resulted in a "still ok" but less linear response.
One solution to maintain the small volume suggested by horn resp would be to design a shorter chamber with the magnet of the driver sticking out, but not sure this is a viable option.
As I write I also wonder if Vrc is the volume of the chamber + the volume of driver (cone + magnet).
So, if supposedly my driver (magnet + cone) occupies a volume of 1liter, a Vrc of 1 liter means I have to design an enclosure of 2 liters.
On such small volumes this makes a big difference.
In the schematic I posted I simply removed the rear chamber from your design to place the focus on the horn profile itself. The mouth area of the conical horn you have specified is far too small for the horn to be suitable for use as a midrange speaker. It will act more like a resonant pipe.
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Thank you for the explanation.
Can you give me a few tips on what the clues to look for are when designing a bass reflex enclosure to know that the cabinet is well optimised for a given driver? Can I for example look at the two electrical impedance peaks to be of approx the same amplitude, in combination with particle velocity of the port not exceeding like 17 m/s at high power with or without filters applied? Are these (or other) more important aspects than trying to get a flat'ish frequency response? When I try to design a cabinet around a driver and pay too much attention on the FR plot I can sometimes see different electrical impedance peak amplitudes for example, makes me wonder if something in my simulated cabinet is bad.
All crossover softwares are based on Thiele-Small parameters which are (normally) not available for compression drivers, and not sure if these parameters can be used to design crossovers for horn loaded cone drivers.
What (if any) software would be suitable to design a 4way crossover for speakers with a direct radiation woofer, a front loaded mid-bass, and compression drivers on the mid-high and tweeter ?
What (if any) software would be suitable to design a 4way crossover for speakers with a direct radiation woofer, a front loaded mid-bass, and compression drivers on the mid-high and tweeter ?
XSIM and VirtuixCad (https://kimmosaunisto.net/Software/VituixCAD/changelog2.html) are often mentioned and have their own threads. I fine tuned a BSC filter for my full range TLs some years back using XSIM but have not done anything more complicated than that. The three-way speakers I assembled long ago came with the crossovers already neatly made so had to put up with any faults.
You're welcome.
I think others are better qualified to comment on how to design bass reflex enclosures.
That would only be relevant for an extremely slow sine sweep, I think. The voice coil can only have one temperature at the time, and the temperature varies slowly (time constants of at least several seconds, minutes or more for big ones). Frequency dependence of power compression would only be relevant for frequencies similar to the thermal time constants of the driver. You won't get a frequency response curve for power compression, or at least the frequency response of the heated Re would be flat above 1Hz.
I think the Hornresp approach is the best that can be done for a simple simulation. You will see how the system compresses at a certain temperature, but Hornresp can't help you to find the temperature or what produces it. To get more accurate, you would need to know the time constants and thermal resistance and capacity of hte system, and probably do a time domain simulation feeding it with a band limited noise or music signal. This could give a time curve of power compression. Maybe Klippel can do something like that, the system can at least measure the driver time constants.
Hornresp Update 5460-230408
Hi Everyone,
CHANGE 1
Two further refinements have been made to the operation of the File Import and File Export forms.
When a file name is highlighted in the export list it is now copied up to the text box for editing if required before the file is exported.
The search string in the text box when the Import or Export form is closed is now retained and displayed the next time that the form is opened.
CHANGE 2
Sound pressure and particle velocity values are now given at S4 in Horn 2 for CH2 designs that do not have stepped segments.
The 'New CH2 Model' PDF file attached to Post #13,442 refers.
CHANGE 3
The cautionary 'S1 < Sd' message that is sometimes displayed on CH2 and CH3 designs that have no throat chamber has been corrected to read 'S2 < Sd', and the corrected message will now also be displayed on CH1 designs that do not have a throat chamber.
The 'New CH2 Model' PDF file attached to Post #13,442 refers.
Kind regards,
David
Hi Everyone,
CHANGE 1
Two further refinements have been made to the operation of the File Import and File Export forms.
When a file name is highlighted in the export list it is now copied up to the text box for editing if required before the file is exported.
The search string in the text box when the Import or Export form is closed is now retained and displayed the next time that the form is opened.
CHANGE 2
Sound pressure and particle velocity values are now given at S4 in Horn 2 for CH2 designs that do not have stepped segments.
The 'New CH2 Model' PDF file attached to Post #13,442 refers.
CHANGE 3
The cautionary 'S1 < Sd' message that is sometimes displayed on CH2 and CH3 designs that have no throat chamber has been corrected to read 'S2 < Sd', and the corrected message will now also be displayed on CH1 designs that do not have a throat chamber.
The 'New CH2 Model' PDF file attached to Post #13,442 refers.
Kind regards,
David