Looking for extreme low loud bass...el pipo, horns,...

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Greets!

Bottom line, low tuned TL or multiple driver IB, with the latter preferred since there's a trend to ever lower content being added to the LFE channel. I saw a measurement awhile back with a near DC cutoff in one of those animated movies, so a bunch of mass loaded drivers in a IB manifold seems the way to go and XO this sub around 35-40 Hz to a somewhat more compact dual driver bass corner horn (or two ;)) such as the LABhorn to get the high res/SQ/'slam' of the most audible portion of the LFE's BW.

GM
 
Greets!

Thanks, I try as best I can.

On what? there's already a horn one and I defer to the 'Cult of the Infinitely Baffled' on all things IB. Regardless, I'm not going to potentially waste my time writing something instructive that just anyone can change without my knowledge/permission.

GM
 
Thank you SO much GM !

Finally some actual numbers I can work with.... now if I could just understand all of these numbers completely, so that I might be able to make any neccessary tweaks.

Correct me if I'm wrong, but I believe the "Alpha" set up you provided the numbers for, is a "half wave" pipe ? ...and of course the Omega is a quarter wave, which is quite workable, but not as efficient.

So back to the Alpha, as I think I can deal with a pipe (or two) of 146 1/4"......

Just a few concerns;

1) What is the actual tuning frequency of this design ? Or, more importantly, how much 20Hz to 25Hz bass will I get with this set up ? {remember, I will be using this set up, in conjunction with a HT that already includes a 12" powerd sub woofer, that should be able to handle mid base, down to 40Hz sub base just fine... I'm really only wanting to reinforce the lower end (40Hz and down)... big time ;-)

2) My sono tube will have to be 10" diameter. The chart shows calculations for a 9.7" diameter pipe. What adjustments do I need to make with the length, amount of stuffing, etc, to keep the performance equal ?

3) Is it advisable to attach a 10" pipe, right flat to the face of a 15" sub (no small enclosure in between, but rather, a flat face plate, with a 10" hole in the center of it) ? I guess this might help to prevent the sub from bottoming out so easily, huh ?

Thanks again GM,
Peace,
Fish
 
Disabled Account
Joined 2004
hum hum, excuse me guys...
should i start a new thread and let you talk in between you ?
It is very cool that you exchange all this info, but id like the thread to stay focussed on my questions :confused:
i mean, the discusion is going here and there...i just dont get it. Should i read all this talking, is it relevant to my questions ? i just dont know !!

i dont have any 18 inches sub, i only have a 12inch one and that is what i want to use, nothing else.

The only thing i understand now is that a horn can get very big if you are not specific enough with your question/spec.

thanks.
 
Should i read all this talking, is it relevant to my questions ?
You mean you didn't already? I think you should, if you read between the lines there is a lot of relevant information to be found.

You can also read the diyaudio wiki about horns.

Basically it comes to this; If you do mind cutting a >20 ft^2 gap in your floor next to the wall/corner, make a TL. I doubt there aren't a few dozen threads about designing one.

Is there any calculators tha i can download and enter my sub specs and "fo" wanted, then it returns most of the dimensions to build the horn ??
Hornresp, but you need more information. Designing a horn won't be easy anyway.

Wkr Johan
 
Disabled Account
Joined 2004
I didnt wanted to sound rude and make every one shut off, i just feel that my question is lost. You can talk as much as you want, i am not the one who can decide about this, but when someone takes its time to start a thread, my thougth are to respect the person and not "hack" the thread with question given into questions.

i read in between the line and there is more info that i need, which is totaly confusing.

I have more questions but i feel that it is going nowhere. Continue to talk in between you guys.

:whazzat:
 
i will try the tl for sure asi have all the material to do it, but i would like to get some idea with my Alpine sub spec, what box dimensions it could be for the horn type.

this sub driver is quite inefficient. 83db 1 watt one meter, If loud is the aim, their are a lot of speakers out there that are much much louder! so if a big bass is important to you, get a different speaker.


Now a 32hz wave is aprox 34 ft, 1/4 of that is ball park 8 ft, a 12 inch pipe, 8 ft long has a volume of aprox 180 litres (does your woofers vas match within x4 ?)

The other serious way of deep deep bass that was mentioned by G.M is the infinite baffle, or extremly large sealed box (up to 4x Vas), compound loaded in a push pull configeration is very nice.

i only have a 12inch one and that is what i want to use, nothing else
Well a big sounding bass is going to be very hard to do with this speaker, why did you buy it in the first place? does it look pretty?

Both of these designs are very simple to build and get right, they are not rocket science, Bass Horns on the other hand are! speaker efficiency is obviously important for filling a big room, not just a car boot and would suggest that you look for one thats over 90db at 1w @ 1metre or invest in one very expensive amp!

The only thing i understand now is that a horn can get very big if you are not specific enough with your question/spec.

no, they are just huge, it has nothing to do with specifics

Out of curiosity, what do you expect to hear between 15 to 25 hz, what music or movies do you listen to? big on pipe organ music perhaps?


I didnt wanted to sound rude and make every one shut off,
well you were and we have! :xeye:
 
Cameron Glendin said:
this sub driver is quite inefficient. 83db 1 watt one meter, If loud is the aim, their are a lot of speakers out there that are much much louder! so if a big bass is important to you, get a different speaker.

I agree with Cameron. In your first post you mention 1000W power handling. This means a big, heavy voice coil and likely lots of power compression at that level.

1000W gets you a 30db increase in SPL. That's 113db/W/m and you'll not get close to that in reality due to power compression. If you start with 98db/W/m sensitivity (there are some 15" drivers that reach this figure), you only need around 30W to reach the same SPL.

High power handling reaches a point of diminishing returns.
 
98db/W/m sensitivity (there are some 15" drivers that reach this figure),
Yes there are lots of good efficient big drivers that get to that level of sensitivity and even higher.
The one factor they have in common is an Fs of between 30Hz and 50Hz and a few even higher.
It's that efficiency vs size vs bandwidth compromise.

Using these type of drivers is great for conventional bass that rolls off above 30Hz and lower if equalisation is used.
For sub-bass use these big drivers need a lower Fs or lots of post equalisation power.

A low efficiency driver does not necessarily have a wider bandwidth, but most wide bandwidth subs are of necessity less sensitive.
 
It's actually very different,

To get 98 dB/W/m the driver has to have an efficiency of 3.98%, this driver has an efficiency of a mere 0,1%.

For a driver with a Fs of 28 Hz to get 3.98%, that would mean Vas has to be 10 times larger (~320 liter/11.9 cu. ft) and Qts 4 times lower (~0.15), than this Alphine.

The Alphine is great for low bass from a relative small enclosure, but if you want it to be loud better stay within 3 ft of it. Just put the opening under your seat ;)

The two most common designs I know, for raising the in-box efficiency would be a bandpass or a horn.
The only horn that's going to get low enough with a relative small mouth would be a Tapped horn.
But if you're up to it you might get nice results with a conventional BLH or FLH.

Wkr Johan
 
Greets!

Actually, with a mere 19.1 mm Xmax it can't to any LF of note without some serious box gain since it's excursion limited to ~40 W, so for this reason a tapped horn isn't viable either. As I previous noted it really wants a huge BLH, but I imagine the floor cutout size would be completely unacceptable even if in a corner, so best IMO to return it to the car's trunk where it was designed to be.

GM
 
Actually, with a mere 19.1 mm Xmax it can't to any LF of note without some serious box gain since it's excursion limited to ~40 W, so for this reason a tapped horn isn't viable either.
Ok, you lost me here :xeye:

Excursion limited to ~40 Hz based on what? Isn't a tapped horn providing neccesary gain as does a BLH? Do you expect a full blast at 15 Hz. Do you suggest to get the frequency response flat down to 15 Hz or do you incoorperated roomgain? (No attacks, just wandering).

For certain drivers I've never seen better predicted low-frequency performance than in a tapped horn, for a given size. I might be completely wrong here but I think a BLH and a tapped horn have a lot in common, which makes it all the more suprising you suggest one, while outruling the other.

Wkr Johan
 
pat allen said:
hum hum, excuse me guys...
should i start a new thread and let you talk in between you ?
It is very cool that you exchange all this info, but id like the thread to stay focussed on my questions :confused:
i mean, the discusion is going here and there...i just dont get it. Should i read all this talking, is it relevant to my questions ? i just dont know !!

Greets!

Well, I was trying to 'kill two birds with one stone' by giving you some of what I consider pertinent info by answering Fish Chris's Qs, but judging by your 'thanks, but no thanks' response you just proved the old adage 'no good deed goes unpunished' :(, so I asked Fish Chris to start a new thread and have a moderator transfer all the impertinent posts lest we overload you with too much data.

Hopefully this will occur soon, but in the meantime, what specific Qs do you have that hasn't been answered?

GM
 
Greets!

~40 W, not Hz. Yes, it does up to a point, but if you look at TD's tapped horn WP there's gaps in the excursion plot like a too small horn has that will bottom out this driver at relatively modest SPLs down where box gain is most needed. A proper BLH OTOH will have a gain inversely proportional to frequency all the way to the desired F3, but the price you pay is a ~basement sized M = ~0.5 hyperbolic labyrinth with a ~9 Hz Fc.

No, I ignore room gain for the most part because in my experience there's isn't much down low due to a typical home's structure being little more than an acoustic power robbing mechanical damper. I'm sure a home in Quebec is pretty solidly built, so won't be as bad, but assuming it will take up all the 'slack' is a 'crapshoot' at best, so plan for the worst and hope for the best since it's better to attenuate than be caught 'short' IMO.

As always though, YMMV.

GM
 
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