Did I do this correctly? Results in Hornresp don't match WinISD

I copied the TS specs from WinISD to Hornresp. The models match fairly well except the port is only 9.7cm long in Hornresp while it is 27.3 cm in WinISD This seems like a huge difference. I did change the model to represent a MLTL in HornResp.

Can someone please check my work?
Lavoce Model.PNG
 

GM

Member
Joined 2003
I copied the TS specs from WinISD to Hornresp. The models match fairly well except the port is only 9.7cm long in Hornresp while it is 27.3 cm in WinISD This seems like a huge difference. I did change the model to represent a MLTL in HornResp.
FYI/FWIW, the current version of WinISD apparently isn't known for very accurate vent designs and MLTL versions of the same alignment will have a shorter vent due to its 1/4 WL TL pipe action damping the vent; the main acoustic reason for using a MLTL or other types of vented TL alignment.

In short, do the comparison in HR to find both the BR and MLTL vent specs.

Also, if wanting folks to check designs, please attach the appropriate doc, so we can just download/install to view the entire project.
 

GM

Member
Joined 2003
Thanks for the replies.

You're welcome!

OK, what you attached doesn't match your posted FR at all, but I'm using the latest version [5310-210913], though doubt it can account for the major differences.

Regardless, shifting the driver down to L*0.349 from the top [L12 = 46.06 cm] per MJK's MLTL design theory matches up 'close enough' once the 6.7 cm offset listed in 'chamber/path' is deleted and can be improved a bit more by changing it to 85.94 cm [rev.L23] + 12.4 cm [L45] = ~98.34 cm.
Assuming you're not using a floor firing vent, it's more accurate to use the offset driver, vented TL in the 'Help/Input Wizard' to accurately place the vent somewhere near the bottom.

In short, max acoustic loading is with the driver at the top, so it lowers it as it's moved down to the next pipe odd harmonic, ergo less pass band 'ripple', so if wanting the driver at the current height with otherwise ~the same response, then it has to be somewhat taller to put the driver at L*0.349.
 

GM

Member
Joined 2003
Will I be able to get rid of this stuff, circled, with some stuffing? What works best at these frequencies? I also need this to have a good response to about 1500 Hz. I assume that the model is not accurate above a certain frequency?

Yes, but it will need to be what some of us consider excessive as it will roll off the bass too much unless backed up hard against the floor/wall junction or in a corner, though positioning here normally has more flexibility.

HR's Loudspeaker Wizard [LW] is based solely on typical polyfil [pillow, etc., stuffing IIRC] evenly distributed within one's [adjustable] input. My 'forever' fave is OC 703 duct board based on the pioneer's [Altec] damping choice for most cab alignments.

Correct, T/S theory 'peters out' at the driver's effective upper mass corner [Fhm]:

Fhm = 2*Fs/Qts'

[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor

[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.

Above Fhm', the driver's effective inductance [Le'] governs its HF response, so with the WAN2300's tiny ~0.7 mH it will in theory be nominally flat on axis out to ~1140 Hz, though by design may not be even remotely accurate, such as a proper [mid] bass horn driver, so just a FWIW/YMMV and why proper measurements are required by 'somebody'.
 
I updated Hornresp. I changed the model between the export and the screenshot. So that is why they don't match. It has been a few years since I have used Hornresp. Both the driver and the port will be offset from the line. I don't know how to model this. Do you have a link to a how-to for this?

The design of the speaker is only in my mind at this point. But I have a few constraints. Tweeter will be a Selenium D220Ti and the woofer is the Lavoce WAN123.00. I own both of these. This is basically an econowave type design.

I want to front port the speaker. This limits where I can put the driver in the line. Unless you have some idea of how I can set it up differently?

The last thing I ran into is that the speaker will not fit in the line as originally modeled. The speaker needs to be 33cm wide (id) to fit the driver and about 16cm deep so the driver vents are not blocked. So L1=528. I am trying to play with the model to keep the box as reasonably sized as I can with these limits.
 
HR's Loudspeaker Wizard [LW] is based solely on typical polyfil [pillow, etc., stuffing IIRC]

Just to clarify, Hornresp doesn't care what type of absorbent filling material is used. All that matters to the program are the values specified for airflow resistivity (Fr1) and thickness (Tal1) of the material. As a useful indicator though, when the airflow resistivity value is less than 1000 mks rayls/m the amount of Polyfill equivalent to the specified material, whatever that may be, is given in kilograms.
 

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