Can anyone here verify that my path length is correct? Driver is 6.5 inches (meaning the center of the driver cutout) from the bottom panel and as far as I know the simulation matches this... Just someone put it into AKABAK (a shorter version) and his path length was different. Note 3/4 inch material.
Attachments
Well yes , sort of , the driver will see the voltage but it may not draw enough current to create the desired wattage if the impedance is high , and it takes both current and voltage to make watts (power) .. .
Nevertheless, with that said i will generally back off the voltage if i am exceeding the driver's xmax rating by much ... If it is just 1mm or 2mm over with one of these high excursion drivers i wont concern myself with it because it is not what you are going to get in real life anyway ... HR doesn't factor in things like suspensions with progressive tension, BL curve slopes, losses etc so just like many other curves in HR (like impedance and "acoustic power" response) the software tends to show exaggerated peaks because it is using a perfect zero loss model unless you use his filling function ..... Using some of David's virtual filling can give you an idea of how peaks and spikes in the graphs are smoothed over and mellowed out to some degree in reality .....
I am also interested to see if we can make the 8th order compound tapped beast work !! I already have a rough idea of how it could be arranged .. We could make it very similar to one of our single fold tapped pipe style boxes except the magnet side of the driver is enclosed in a chamber with a port leading up into the exit of the main pipe just a few inches away from the mouth/terminus of the cabinet .........The box would have to be taller than a regular transflex/tapped-pipe because we would have to make up for the path length taken up by the small chamber ... With the use of some mass loading we should be able to keep the box from becoming terribly tall though .... A double fold could also be an option to keep box height down .. ..
Last edited:
I'm more worried about thermal handling than excursion, all of your simulations over 64 volts are seeing about 600-700 watts at certain frequencies. I wouldn't hope for much past 65 volts if you want to have the driver last at high power levels. HT - fine, High level music usage -- no. Regardless I'm rather keen to try a simple TH alignment as suggested by someone since it has about the same average SPL as can be expected from this 8th order thing and it only requires 1 angled baffle piece and no ports. I'll get back to you with dimensions. Tapped horn has 2 dB more output from 35-50 and above 80 Hz, May need to learn to fold a bit to get the height down though.
Last edited:
Ok , here we go
I am pretty proud of this one
Version 3
Still a very simple design, and this one is 100% compatible with HR's segments, chambers and ports so this curve should be close enough to what you will get in real life
I plan to make this my final version of the ML-Transflex for the LAB15 special..
I will get a sketch drawn up for this thing tomorrow , dimensions are very similar, i just have to extend one dimension to allow for a few more liters of internal volume ...
- Great output
- Low group delay
- Excursion stays below 13mm at a full 58v (600w)
- driver is easily accessible without the use of a removable panel
- efficient use of cabinet volume, no wasted space
- simple single fold design, easy build, all straight panels, no angles
- acoustically shortened path by use of a mass loading constriction, which is a long vent at 50% of the main pipe's area, velocity should not exceed 20 m/s in worst case scenario in the real world.(calculated by multiplying the velocity at mouth (*2 for the 2:1 mouth/port area ratio)
- Very affordable driver $134 shipped, get em while they last!
- Woofer's motor is located in the mouth (the high velocity end of the pipe) which maximizes cooling of the voicecoil ! Which equates to reduced thermal compression when used at high SPLs for extended periods of time.. Longer life, and more output!
- well balanced bass output, just the right amount of damping.
Do you know the external dimensions of the revised enclosure?
The multiplier can be made more conservative, as long as a person is consistent and uses the same multiplier for all of his/her sims then they are getting a fair comparison between drivers & designs ..... I use 1.5 as my multiplier but a more conservative figure to use would be 1.3, so in that case a driver with an RE of 3.5 ohms would be considered a 4.55 ohm driver, and thats the number you would punch into the "load impedance" field within HR's Eg popup window ...........
Anyway, the RE/Impedance multiply method thing sounds weird i know, and its already been covered once in this discussion so i don't want to sound repetitive or hounding like the cantankerous old coot that im trying hard not to become in my old age ....
heheand Yep, the reverse taper pipe is a simple and effective option to reduce path length too, you should give it a sim to see if it is suitable for the SWS ...
Just tried it, working with different depths. Isn't really reasonable for a shorter length, needs too much dept to be "compact". Roughly 9.2 cu. ft. Has a massive spike at 39 Hz of 127 dB and 107 Hz of 131. With filters can be made 123 +- 1 dB pretty flat, so 1.5-2 dB for 50% more volume and required dsp.
Last edited:
The multiplier can be made more conservative, as long as a person is consistent and uses the same multiplier for all of his/her sims then they are getting a fair comparison between drivers & designs ..... I use 1.5 as my multiplier but a more conservative figure to use would be 1.3, so in that case a driver with an RE of 3.5 ohms would be considered a 4.55 ohm driver, and thats the number you would punch into the "load impedance" field within HR's Eg popup window ...........
Anyway, the RE/Impedance multiply method thing sounds weird i know, and its already been covered once in this discussion so i don't want to sound repetitive or hounding like the cantankerous old coot that im trying hard not to become in my old age ....
and Yep, the reverse taper pipe is a simple and effective option to reduce path length too, you should give it a sim to see if it is suitable for the SWS ...
I just don't see the use of a multiplication factor because as a speaker designer you have to design the speaker not to fail, that is why we have voltage limits and not watt limits, we set our voltage limit to where in our particular design with whatever impedance curve/cabinet displacement information we have available to keep it under the RMS power rating of the driver. You can also set a soft limiter that has a short attack/release to get a little more transient output out of the sub but that is splitting hairs
.Can someone explain the difference between when to use tapped horn mode vs ND mode for a tapered or straight pipe? Are they always ND? Is it a simple horn or something else because TH's sim with large peaks at fb and ~110 and if you switch to ND mode (for practically the same dimensions) things change all of a sudden and they flatten out. Obviously the software treats the boxes differently under different settings, what I'm trying to figure out is which mode to use when doing a reverse taper or a straight pipe.
I just don't see the use of a multiplication factor because as a speaker designer you have to design the speaker not to fail, that is why we have voltage limits and not watt limits, we set our voltage limit to where in our particular design with whatever impedance curve/cabinet displacement information we have available to keep it under the RMS power rating of the driver. You can also set a soft limiter that has a short attack/release to get a little more transient output out of the sub but that is splitting hairs
Its just noteworthy and even useful for the purpose of making fair comparisons and making sure that close to the desired amount of power is actually being applied to the model, it can make a difference when scrutinizing extremely small changes in output when attempting to optimize our cabinets and picking the very best drivers for every last decibel of performance that you can squeeze out of a design..Or comparing two different cabinets loaded with two different drivers...
In a real-world scenario (if one were nitpicky) an RE & Impedance on the high side would need more voltage as well in order to reach the desired wattage , BUT in the real world the difference of a couple of volts at this power level wont be detectable to anyone's ears ....
In real life nobody is really going to notice the difference between 53v and 59v (a difference of 1 decibel) but we will notice it in simulation and i think that is useful for optimizing things since we often do that process one hair at a time ...
Last edited:
Beau ,
The external dimensions will be very similar, i think i will try to keep the same width and depth, and just increase the height by approximately 2 inches to make room for the additional 10 liters of internal airspace
I didn't think it was possible either and i have been working with HR for more than a few years now.. ..I cannot believe that I hadn't noticed this before now .. Or maybe i did and just couldn't get it to work so i didn't think anything of it ...
I suppose the term "8th order" could be applied to this if a person considers a tapped-Pipe (transflex) or tapped horn to be an equivalent to a 6th order series tuned bandpass (and i do know that some people consider them to be) ... This twist on the design adds an extra chamber and port that encloses the side of the driver closest to the mouth , then the new port fires into the area thats still inside but not far from the mouth... That new set adds two more orders technically ... *shrug*
I guess a constriction/port in the main pipe would kind of seal the deal and make it fully official by defining the additional chamber & port set ..
Not sure how "picky" it will be , i suppose i could adjust driver parameters and see ..
Last edited:
Hi MMJ,
Only if the value of Qes is much smaller than the value of Qms to begin with.
Showing them "Donald in Mathmagic Land" would be a good place to start. I saw it myself more than 50 years ago, and have never forgotten it.
Donald in Mathmagic Land - Wikipedia, the free encyclopedia
Kind regards,
David
Only if the value of Qes is much smaller than the value of Qms to begin with
.Showing them "Donald in Mathmagic Land" would be a good place to start. I saw it myself more than 50 years ago, and have never forgotten it.
Donald in Mathmagic Land - Wikipedia, the free encyclopedia
Kind regards,
David
Hi MMJ,
The functionality has now been changed. Thanks again for the feedback.
http://www.diyaudio.com/forums/subwoofers/119854-hornresp-480.html#post4037350
Kind regards,
David
That video is fantastic! I saw it for the first time a few months ago with a friend of mine sent me the link to it on youtube .... I agree , it should be required viewing for every student
Excellent! Thank you for looking into that David , i hope it wasn't too much hassle .. .
Will both the wiz and main have the popup with the "prompt" switch on? or did you find another way?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.