kstrain, do you want to say, that if i get the resonators right, there will be no other effect of the horn, which lets the sound be ugly? This is what i want to know: if a flat frequency response equals a good sound or if there are mechanisms in a tapped horn, which make the usage above normal passband not rewarding.
hm, what if i used 60db/oct linear phase filters? My current setup uses digital filtering, so i can avoid low order active crossovers.
hm, what if i used 60db/oct linear phase filters? My current setup uses digital filtering, so i can avoid low order active crossovers.
MaVo said:
Perhaps I understand your question a little better now.
"no other effect" - perhaps I'm forgetting something, but if the response is flat (and minimum phase) it should be like any other flat response. There are some big panels that could resonate unless braced.
On the other hand I'd be astonished if it can be done well enough in practice. I suspect modelling will not help so much, because the losses are not likely to be known accurately.
Ken
ok i have a problem
i made the horn, the top is ready to be screwed on, screws are spaced every 15cm so it will be plenty, now with the bottom side i glued and screwed, and then used sealant all around and up the side walls
now for the top.... i have to make it removable incase the driver ever blows or i will have to smash it open,
i need to seal the top side, but only with something that is airtight, but nod adhesive in any way
i was thinking of bluetack, but maybe strips of very thin rubber or foam would be better, any ideas?
i made the horn, the top is ready to be screwed on, screws are spaced every 15cm so it will be plenty, now with the bottom side i glued and screwed, and then used sealant all around and up the side walls
now for the top.... i have to make it removable incase the driver ever blows or i will have to smash it open,
i need to seal the top side, but only with something that is airtight, but nod adhesive in any way
i was thinking of bluetack, but maybe strips of very thin rubber or foam would be better, any ideas?
Is this a bad idea?
I have a tl. It was originally supposed to be a tapped horn (years ago) but that's a whole other story (the tap location is bad and I thought I'd try a reverse taper). Now that I can model what I did with Mr McBean's hornresp I can see how bad that design was. Thankfully it has been a great tl design, since I moved the driver to the outside of the box and added some stuffing.
So far this box has been -
1. a really bad reverse tapered tapped horn
2. 15 hz tqwt
3. 12 hz ml tqwt
4. under investigation to be used as a positive tapered tapped horn
Although there is nothing wrong with the box as is, it was always meant to be a tapped horn and it still might work. Since it would be free I've been thinking about trying it. I modelled all the drivers I have onhand and the dayton quatro 15 yeilds the smoothest curve - let's call it +/- 2 db from ~ 20 - 70 hz.
The reason that I'm asking if this is a bad idea is because this is not very similar to most of the designs being posted here.
1. not a high taper ratio - some of the designs I've seen here have a taper ratio as high as 1:13, mine is only 1:2.
2. the tuning frequency is at or very near the driver's fs
At this point I don't think either of these are bad things, but I'm open to opinions.
The tap location was chosen to kill the first problem harmonic at 95 hz. Using .5 pi space, the next problem harmonic is not so bad either, and could probably be beat down with only a 12 db/oct xo at 80 hz (or lower if the 70 hz bump is troublesome). The internal volume is 325 liters (11.5 cubic feet). 150 - 200 watts yeilds 125 db capability from 20 - 80 hz (in .5 pi space).
Overall, this is not the smoothest curve (could use some extra Le and maybe a touch of eq), and some designs using a 10 inch driver can do about the same output in a similar sized enclosure. On the other hand, overall output for my proposed tapped horn looks to be at least as high, if not higher than the same driver (dayton quatro 15) in a 6th order bandpass with similar measurements (11.5 cubic feet total volume).
Considering the extensive internal bracing the mods won't be easy but with the right tools shouldn't be too hard either.
Is it a bad idea?
I have a tl. It was originally supposed to be a tapped horn (years ago) but that's a whole other story (the tap location is bad and I thought I'd try a reverse taper). Now that I can model what I did with Mr McBean's hornresp I can see how bad that design was. Thankfully it has been a great tl design, since I moved the driver to the outside of the box and added some stuffing.
An externally hosted image should be here but it was not working when we last tested it.
So far this box has been -
1. a really bad reverse tapered tapped horn
2. 15 hz tqwt
3. 12 hz ml tqwt
4. under investigation to be used as a positive tapered tapped horn
Although there is nothing wrong with the box as is, it was always meant to be a tapped horn and it still might work. Since it would be free I've been thinking about trying it. I modelled all the drivers I have onhand and the dayton quatro 15 yeilds the smoothest curve - let's call it +/- 2 db from ~ 20 - 70 hz.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The reason that I'm asking if this is a bad idea is because this is not very similar to most of the designs being posted here.
1. not a high taper ratio - some of the designs I've seen here have a taper ratio as high as 1:13, mine is only 1:2.
2. the tuning frequency is at or very near the driver's fs
At this point I don't think either of these are bad things, but I'm open to opinions.
The tap location was chosen to kill the first problem harmonic at 95 hz. Using .5 pi space, the next problem harmonic is not so bad either, and could probably be beat down with only a 12 db/oct xo at 80 hz (or lower if the 70 hz bump is troublesome). The internal volume is 325 liters (11.5 cubic feet). 150 - 200 watts yeilds 125 db capability from 20 - 80 hz (in .5 pi space).
Overall, this is not the smoothest curve (could use some extra Le and maybe a touch of eq), and some designs using a 10 inch driver can do about the same output in a similar sized enclosure. On the other hand, overall output for my proposed tapped horn looks to be at least as high, if not higher than the same driver (dayton quatro 15) in a 6th order bandpass with similar measurements (11.5 cubic feet total volume).
Considering the extensive internal bracing the mods won't be easy but with the right tools shouldn't be too hard either.
Is it a bad idea?
Naudio said:is there anything to stop me making a few of these and selling them to my friends?
or maybe even to the local club? or will tom danley sue me?
Legally the position on patents is clear -- making stuff for yourself (i.e. not for profit) is allowed, selling it isn't.
In reality, whether Tom (or his lawyer) would come running after you would depend on whether you started to make a big business of it (losing Danley potential sales) or not...
Ian
just a guy, i think it looks quite nice. i agree with gm.
Naudio, i see it this way:
- making profit of friends is not nice to your friends, but to let your friends give you the production costs is obviously the thing to do. also, they should help you with the work. this way they will love their new subs much more.
- making a profit of it will be bad for the diy community. we live of the knowledge, which inventors like thomas danley give us for free. if we make money from their gifts, they wont share their knowledge next time they have something new.
Naudio, i see it this way:
- making profit of friends is not nice to your friends, but to let your friends give you the production costs is obviously the thing to do. also, they should help you with the work. this way they will love their new subs much more.
- making a profit of it will be bad for the diy community. we live of the knowledge, which inventors like thomas danley give us for free. if we make money from their gifts, they wont share their knowledge next time they have something new.
Absolutely, I am allready having fun preparing, and rather sooner than later, I hope, I will start building.
MaVo, I didn't realise the differences I was looking for was that subtle, but now I can see what you are driving at. My problem is that I don't master the tech. talk as yet, so I have a problem realising which driver has a stiffer suspension than a comparable driver. How do you define a stiffer suspension?
Regarding large Xmax, what is large Xmax, one way, or to put it differently, I guess there will be a minimum value for Xmax that it would be unwise to go lower than for inclusion in a TH? I've put 9 mm as my own lower limit.
I will let go now, in my quest for the suitable driver, if I only can get a grip on the stiffness issue. I is high time to get started with Hornresp, and we don't like each other much
buggsson said:
Choose fs, if the cone is relatively heavy for a given fs, that means that the stiffness must be high too. Don't worry about stiffness per se.
fs is determined only by mass and stiffness, more mass brings it down, more stiffness increases it, in fact it is fs^2 that changes in proportion to stiffness
Hornresp is the easiest way (except copying someone's design).
Ken
Thanks GM and Mavo. Initially I was a bit worried about the 2 bumps in response at either end of the bandwidth, but I'll likely use a plate amp to power it, which will likely have either a 12 db/oct rumble filter at about 25 hz or like the partsexpress plate amps it may only be flat to about 30 hz, so that should take a bit of the bite out of the first harmonic bump, and the second one can be easily controlled with the plate amp's 24 db/oct low pass filter.
To make the tl loud enough for serious spl movie watching in a moderate or large sized room at the current low tuning I would need at least one and maybe 3 more of them. That was the plan but I don't think the maw15 I was using is even available anymore. The quatro 15 I used previously is still available although I noticed that today it is sale priced at $106, not sure how much it goes for at full price now but I bought mine for $75 just a couple years ago (although the exchange rate was 40 percent back then).
The 8 pack price of diycable's new IB/dipole specific driver is $105 each, and with 22 mil xmax it's got over 2x the quatro's displacement. Weight is similar for these 2 drivers at ~ 20 lbs and CDN $ is at par with USD (for now). It's way too cheap now to do anything other than IB for VLF projects.
The tapped horn (and maybe even my imperial) may be due for some major remodelling, but the next REAL new project will be IB.
To make the tl loud enough for serious spl movie watching in a moderate or large sized room at the current low tuning I would need at least one and maybe 3 more of them. That was the plan but I don't think the maw15 I was using is even available anymore. The quatro 15 I used previously is still available although I noticed that today it is sale priced at $106, not sure how much it goes for at full price now but I bought mine for $75 just a couple years ago (although the exchange rate was 40 percent back then).
The 8 pack price of diycable's new IB/dipole specific driver is $105 each, and with 22 mil xmax it's got over 2x the quatro's displacement. Weight is similar for these 2 drivers at ~ 20 lbs and CDN $ is at par with USD (for now). It's way too cheap now to do anything other than IB for VLF projects.
The tapped horn (and maybe even my imperial) may be due for some major remodelling, but the next REAL new project will be IB.
i agree with kstrain, i also mostly look at fs. if i want a 20hz th, i would go for about 30hz fs, but it can differ. I think i will build a 20hz th with my 45hz 12 inch drivers, since they model fine enough for me. additionally, ts param are not so important, as you can change the horn parameters to make it fit to a certain degree.
one advice i would like to give is to keep the mouth size low, because the bigger it gets, the smaller will the benefit of a th over a normal frontloaded horn be. around 2 times the sd seems to be a good starting point.
one advice i would like to give is to keep the mouth size low, because the bigger it gets, the smaller will the benefit of a th over a normal frontloaded horn be. around 2 times the sd seems to be a good starting point.