bass horn with 128h

[kawmic]

I'm looking for drawings of bass horns with 128h speakers.
Obviously this is a high-end project. So, it should be linear between 30 and 100 hz.
Size doesn't matter!! (no annoying wife;))
Don't know a whole lot about the theory about bass-horns. But, please specify the increase in effeciency and curves so i can see the frequency response.
Kindly Michael

[Mostlydiy]

Hi Michael,

I can´t give you a concrete plan for a bass horn, but I could give you an advice regarding the driver. I have no first hand experience with the driver but by looking at the T/S parameters, this driver seems to belong in the vented box department. Low Fs, low BL and a little bit to high Q. I know you said the size of the horn wouldn´t matter but if we are talking 30Hz then we also are takling around 1m3, probably even bigger. Ive been in bass horn thoughts for a long time but been put of mostly because the size issues.

/Moslty

[Lee in Montreal]

Linear (flat) down to 30Hz means a 5.75m long horn path (half wave). I am sure you have other options to reach your goal.

[kawmic]

ok, what if i restrict size to, 2.5-3meters wide and depth to 3meters and hight to 1meter?
as i said before, i don't care about size. if i have to build the cabinet in my room above the livingroom, i will;)
all that matters is the sound.
PS: i have 4 128h's

[Lee in Montreal]

all that matters is the sound.
PS: i have 4 128h's

Then sell your 128h and get drivers suitable for a horn. ;) BTW Why a horn?

[kawmic]

because of their sensitivity (91db). i wanna use 128h's because i love their sound;)

[more10]

Michael

Swap the 128h for something better suited for horns, or pipes. The fs is a bit too low. If you want to reach 30 look for a driver with fs around 35-40 Hz. Check out the hornish pipe (http://www.audioheritage.org/vbulletin/showthread.php?33531-My-30-80-Hz-2226-quot-horn-quot) I made for the 2226.

[kawmic]

Ok. i don.t like 2226's. i wanna use my 128h's. what do you suggest then? should i strive for lower bass, say 25hz?
what about a cab with 2 or more 128h's?

[Lee in Montreal]

because of their sensitivity (91db). i wanna use 128h's because i love their sound;)

You wont like their sound outside of a bassreflex cabinet. It seems you are pretty new at "all that" and I suggest you read a bit about the principles and requirements of horn loading. The internet is your best friend.

[kawmic]

why can't i use 128h's?

[Lee in Montreal]

why can't i use 128h's?

Reread previous posts. Especially post #2. It was kindly explained right from the beginning by Mostlydiy. BTW Have you also gathered the T/S parameters for your 128 to verify if it can be used in a horn? Have you read about horn loading?

[kawmic]

yes i have all parameters. where do you suggest i read about basshorn principles?
and if i use a unit with higher fs, wouldn't that affect the deep bass?

[Mostlydiy]

Michael,

When I were new to horn loading speaker I asked a similar question at Romys site and the answear "You have to do your homework". I was kind of annoyed by the reply put the more I studied horn principles the more I realised that its quite a complex design. I would advice you to learn to use Hornresp and play around with it. Its quite hard to get into but its a wonderful tool when simulating horn enclosured coupled with different drivers. When you are familiar with the program you will see for yourself why the 128 isn´t very well suited for hornloading. I belive that there is a several hundred sites long thread about that software on diyaudio.

/Mostly

[kawmic]

so i'm gonna look for a program called hornresp?

[kawmic]

ok, i found it. thnx for all your help;)

[more10]

if i use a unit with higher fs, wouldn't that affect the deep bass?

When building a horn, you should look for a driver with higher fs than the horns low cut-off. You also want a driver with low Q, a low Q driver will work below fs in a horn. You also want high BL, typically above 20.

A true horn will be very large, typically 2 cubic meters for a horn reaching 25 Hz and placed in a corner. In order to make the horn smaller it can be made more like a pipe, with a much smaller exit area, like the ones I linked to above. This type of horn will be bandwidth limited, but since you only want to reach 100 Hz, this might be just what you are looking for. But these "horns" doesn't like drivers with typical horn parameters, they like higher Q and lower Bl.

Since you are Danish, you can understand my thread Hornteori @ hififorum.nu (http://www.hififorum.nu/forum/topic.asp?TOPIC_ID=82144), it has links to a lot of interesting horn stuff, especially the writing by Bjørn Kolbrek.

Mårten

[more10]

You also want to use a driver with a reinforced cone in a horn. The forces on the cone will be much higher in a horn than in a BR or a closed box.

[Lee in Montreal]

Why not simply build a pair of bass reflex cabinets with two 128h in each? The mutual coupling will add 3db in efficiency which could help those low efficiency drivers. Bass reflex cabinets are very easy to figure and take less space.