I did a quick review of the scripts on this page and it looks like they are correct from what I have seen elsewhere, but it occurs to me that I really don't know if 'elsewhere' is correct, either.
I wonder if anyone else could corroborate by entering some known solutions and comparing the results.
Speaker Enclosure Calculations (NOTE: I edited the URL text because it was mis-leading people)
Thanks in advance,
Jeff
I wonder if anyone else could corroborate by entering some known solutions and comparing the results.
Speaker Enclosure Calculations (NOTE: I edited the URL text because it was mis-leading people)
Thanks in advance,
Jeff
Last edited:
They are a good starting point but often the published values for FS, QTS, VAS etc. for your driver are not quite correct. Most serious builders will end up breaking the driver in for a while and then measuring these values themselves. Then there are a number of other considerations like will you use a passive crossover if so this will change the driver's QTS or if you use some damping material in the box this will make the apparent volume of the box larger.
I am leaning towards a Vented design to extend the bass performance of a full-range driver, so there are not going to be any crossovers in the box. It's going to be a small driver (PS95-8, based on the blind ratings in another thread) and a smallish enclosure (~2.8 liters).
The plan is to 3D print the enclosure with a resin (haven't decided which one, yet), so I was hoping that the formulas were accurate. Not only would it be expensive to experiment, but I'm not familiar enough with enclosure design to know what to change.
I can accurately model everything, so it will be pretty straight-forward to subtract out the volumes used by the driver, amplifier, etc., which is why I was hoping that accurate numbers in will result in good performance out.
Jeff
The plan is to 3D print the enclosure with a resin (haven't decided which one, yet), so I was hoping that the formulas were accurate. Not only would it be expensive to experiment, but I'm not familiar enough with enclosure design to know what to change.
I can accurately model everything, so it will be pretty straight-forward to subtract out the volumes used by the driver, amplifier, etc., which is why I was hoping that accurate numbers in will result in good performance out.
Jeff
A few things to consider:
1- Looking at the product page on parts express, they've already done some modeling for both a sealed and ported enclosure for this driver. The size for the ported is closer to 3.2 liters. Any particular reason not to follow their recommendation?
2- Extended bass performance from a 3-1/2 inch driver is sorta relative, as there isn't much moving surface area to generate a lot of low frequency energy. Still, it depends on your usage and requirements for low frequency extension.
3- Driver efficiency is shown at 85.56dB@1Watt. There are more efficient drivers out there which could reduce power requirements and yield higher SPLs. Some of Faital Pro 3- and 4-inch drivers come to mind, which are rated at 91dB@1watt.
Regards, KM
1- Looking at the product page on parts express, they've already done some modeling for both a sealed and ported enclosure for this driver. The size for the ported is closer to 3.2 liters. Any particular reason not to follow their recommendation?
2- Extended bass performance from a 3-1/2 inch driver is sorta relative, as there isn't much moving surface area to generate a lot of low frequency energy. Still, it depends on your usage and requirements for low frequency extension.
3- Driver efficiency is shown at 85.56dB@1Watt. There are more efficient drivers out there which could reduce power requirements and yield higher SPLs. Some of Faital Pro 3- and 4-inch drivers come to mind, which are rated at 91dB@1watt.
Regards, KM
The PS95-8 got a lot of votes in a recent blind comparison here in DIYAudio.com and it is much more attractively priced than the two units which out-polled it, so I am starting with it. A Tectonic BMR driver is being tested in the next round and I may consider that, too.
Not looking to rock the room or to drown out the neighbors, but I do want the best performance I can get out of a modestly-priced remote speaker.
I will, however, take a look at the Parts Express page. Thanks for the advice.
Jeff
Not looking to rock the room or to drown out the neighbors, but I do want the best performance I can get out of a modestly-priced remote speaker.
I will, however, take a look at the Parts Express page. Thanks for the advice.
Jeff
Whom to trust is precisely why I started this thread. The link in the first post provides results based on the selected speaker's published data, but I don't know if it's correct.
I also don't know if Parts Express is correct. There is a YouTube video where an employee of another audio store presents a tutorial on speaker design that is roundly criticized in the Comments section and I don't know which side to trust there, either.
Whichever decision I make here will be criticized by someone (after all, this site is "by fanatics, for fanatics"). One person who replied to my post on another thread about using a horn in a smaller enclosure said it wasn't a "real horn" unless it was a quarter wavelength at the mouth (which is entirely too much for my wall, let alone the WAF).
Jeff
Trust is an odd concept. One could easily make a case that forums aren't to be trusted for the simple fact that anyone can post anything without having any knowledge. If the reader has no knowledge, they won't know the difference between a subject matter expert and a moron, sad but true.
In any case, the P-E spec noted that they used Bassbox6, which would also require plugging in the T&S parameters and then interpreting the results and fine tune it a bit.
I would also agree (with richie boy) that building a simple wooden box first would be beneficial and allow you to determine if your existing design is going to get you where you want to be.
On a separate note, which 3D printer are you using and have you decided on the material yet?
Regards, KM
That's why I am throwing it into a cauldron surrounded by 'fanatics'. I figure you all will burn away the chaff. 
I am considering the design of a re-sizable box (and wondering how well that would work for evaluating specific speaker drivers).
As for the 3D Printer I'd use, it depends more on the material I select and who is providing the service. So far, I've made some plastic and metal objects at Shapeways. Protomold is who I think of for making a mold and doing a production run.
The materials I am considering are in the attached spreadsheet (also provided as an image for those of you who don't want to download and extract from an archive).
Jeff
I am considering the design of a re-sizable box (and wondering how well that would work for evaluating specific speaker drivers).
As for the 3D Printer I'd use, it depends more on the material I select and who is providing the service. So far, I've made some plastic and metal objects at Shapeways. Protomold is who I think of for making a mold and doing a production run.
The materials I am considering are in the attached spreadsheet (also provided as an image for those of you who don't want to download and extract from an archive).
Jeff
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.