Bass Horn

[Dr.db]

Hey folks,


me and a couple of friends are planing to build a little PA for outdoor use.

The Tops are JBL: 2402,2260 & 2*E-110(frontloaded horn)
The amp for the bass-section is an old and heavy(80lbs) Bose 1800 with aprox. 250.w @8ohms....
The subwoofers shell be running down from 40hz up to 150hz....
Cause of the little power we got the subs must have a very very high sensitivity!!

Im not shure which drivers to use and which enclosure will fit best...? :dont-know
....i thought about using 2226 in the 4530 scoops.
But I recon they wouldn't go deep at all and sensitivity isn't that good too.?!?
The usual sensitivity of the 2226 is 97db. Is it 103db in the 4530 scoop?
How about a 4520 with two E-140 !? Would that be 106db?


Which other horns would be better for my use ?


Thanks a lot for your help!!!
Best whishes from germany,
Olaf

[Zilch]

http://www.audioheritage.org/vbulletin/showthread.php?t=24695

[jcrobso]

The horn loading tends be a little more efficient than the driver's direct radiation so crossing over at 150 is a good idea. Over the years subs in big boxes have replaced bass horns, mainly because of the size of bass horns.
For the same size box you can get two 18" drivers and get down to 30hz. Horn loading gets you the most db per watt, John

[jbl4ever]

http://www.jblpro.com/pub/obsolete/low_frequency_enclosures2.pdf

[Dr.db]

Horn loading gets you the most db per watt, John

So horn loading is the only possible way for me.
Since I got just 250.watts @ 8ohms...


Is there any sense in using old E-140 or E-145 instead of new 2226 ?

These speakers shell reproduce up to ~150hz, above 150hz the E-110 will get
on... So does the 2226 a better job then the E's? Or does a E-140/145 has a higher efficiency ?





Would you guys build a 4530 or 4520 when powering with 250.watts??




Thanks a lot so far!!!
For the links and for the ideas :)

Olaf

[CONVERGENCE]

Hey folks,


me and a couple of friends are planing to build a little PA for outdoor use.

The Tops are JBL: 2402,2260 & 2*E-110(frontloaded horn)
The amp for the bass-section is an old and heavy(80lbs) Bose 1800 with aprox. 250.w @8ohms....
The subwoofers shell be running down from 40hz up to 150hz....
Cause of the little power we got the subs must have a very very high sensitivity!!

Im not shure which drivers to use and which enclosure will fit best...? :dont-know
....i thought about using 2226 in the 4530 scoops.
But I recon they wouldn't go deep at all and sensitivity isn't that good too.?!?
The usual sensitivity of the 2226 is 97db. Is it 103db in the 4530 scoop?
How about a 4520 with two E-140 !? Would that be 106db?


Which other horns would be better for my use ?


Thanks a lot for your help!!!
Best whishes from germany,
Olaf


The 4520 and 4530 are short throw rear loaded bass horn that become direct radiators above 150hz. Recommended speaker 2205. No sensitivity gain.

The 4560 and 4550 are front loaded horn long throw with a 6db sensitivity boost above 100 Hz. Recommended drivers are 2220 and 2205.

......................................

[Dr.db]

Thank you.


Which enclosure (horn) and driver do I need for sensitivity gain below 100hz ?
....it should be well over 100db/m/w
....Size does not matter a lot

[CONVERGENCE]

Thank you.


Which enclosure (horn) and driver do I need for sensitivity gain below 100hz ?
....it should be well over 100db/m/w
....Size does not matter a lot


None ,only the 4560 and 4550 will add 6db above 100hz.

[Dr.db]

And how much amp-power is ideal for one E-140/145 ?

Sine-Power! ...not music-, peak-power or whatsoever....





Could I simply build the hornmouth of the 4560 aprox. 50-60cm deeper to achieve sensitivity gain from ~70hz instead of 100hz....!?

[subwoof]

The rear loaded scoops *do* add sensitivity - the peak is around 60hz. Look at the JBL graphs ( note the zero line ). the boost is much lower in frequency than the 4550/60


:o)

[Hoerninger]

A bass horn up to 150 Hz should be frontloaded and should have horn support for its lowest part too, no bass reflex.
When driven with a compression chamber the results are improved efficiency and a smoother frequency response.
The response shown below is for a room corner. When driven in front of a wall there is a slight roll off and above 100 Hz increased peaks and lows, but still good for usage. The sound pressure level will be decreased by 3 dB of course.

Just an example which might be possible.
___________
Peter

[Dr.db]

The rear loaded scoops *do* add sensitivity
- the peak is around 60hz. Look at the JBL graphs ( note the zero line ).


How much?
What sensitivity do the scoops have at 60hz eg. 100hz ?

Sorry for asking soo often, but it's quiet important for me to know...



And thanks to Hoerniger for the simulations!!!

[paragon]

Sieh das nicht so eng. Die 4530 geht bei Eckaufstellung bis ca 40 Hz runter. Das Lautsprecherchassis ist hier nahezu egal. Die Lautstärke ist allemal groß genug. Ich habe diese schon in einer Discothek gehört, reicht locker, laut und tief genug. Die 4520 geht noch ca 10 Hz tiefer bei gleichen Bedingungen.
Die 4530 steht bei mir in einem 12 qm Raum in den Ecken. Geht tadellos.

[Dr.db]

@Paragon
Hallo,

die Bassrutschen werden ausschließlich draußen eingesetzt, dort gibt es leider nirgends Ecken...
Ob die Lautstärke groß genug ist....!? sehr relativ...
Ich frage deshalb so akribisch nach dem Wirkungsgrad; denn wenn dieser nicht größer ist als wie bei einer regulären Reflex-box dann muss ich mir beim bauen nicht die Arbeit mit dem Horn machen ;)

Besten Dank & Schöne Grüße,
Olaf


@Paragon
Hello,

the scoops will run outdoors only, there aren`t any corners at all.
If soundpressure will be enough....!? ....quiet questionable...
I`m hanging onto this question(if sensitiviy is higher than Reflex/vented), because if this isn't so, I won't have to spend plenty of time building scoops when bassreflex will have same sensitivity ;)

Thanks alot & Whishes,
Olaf

[Paul D]

This site has some interesting designs for horn subs. I built a lab 12 sub which is a similar design and it had high output to about 30hz. Some of these designs use the 2226 or cheaper alternatives.

www.billfitzmaurice.com (http://www.billfitzmaurice.com)

[Hoerninger]

I have made a simulation for the JBL 4530 based on this plan (http://www.audioheritage.org/vbulletin/showpost.php?p=9988&postcount=4) with the speaker JBL 2226H.
Front chamber 37 l
throat area 505 cm^2
horn length 164 cm
mouth area 3243 cm^2,
combined response of horn and speaker standing on a floor without walls.

For comparison there is a rough frequency response of the 4530 with the speaker 2205 (http://www.jblpro.com/pub/obsolete/low_frequency_enclosures2.pdf).
____________
Peter

[Dr.db]

Looks like 2~3db gain between 70hz-150hz....!? Right?

[Hoerninger]

For the simulation I have choosen the combined responses from the cone and the horn mouth. The path lenght difference was choosen with 0 cm.
The first picture shows the horn with the original 2205, the second with 2226.

For the first two simulations there is a amazing conformity of the lowest two frequency dips compared the response shown in post 16. The simulation must show deeper cuts as the program does not take care for different path length from the cones back to the horn throat.
Additionaly the simulation shows that the maximum at about 250 Hz is a bit lower than that at 700 - 1000 Hz.
The simulated response above about 350 Hz must be taken with a grain of salt, as the program assumes the cone to behave like a rigid piston. Nevertheless the abrupt fall off at about 700 hz can be seen in the simulation too.

At 46 Hz the simulated response is 6 dB down compared to 70 Hz.

In the third simulation the horn is not assumed to be in a corner (0,5 Pi) but standing free on a floor (2Pi). The differences are obvious.

The data entry field for the 2226H working in a corner is added.
____________
Peter

[Hoerninger]

Same horn with JBL 2226H but front loaded and standing in a corner.
The back chamber is choosen with 55 l.
The volume between cone and throat is reduced from ca 34 l to 3 l.

The grey graph showes the result for 2Pi.
____________
Peter

[Dr.db]

Thanks a lot Peter!!!


I believe the simulations show me I gotta go with the 2226h in a frontloaded horn.
This one does go as deep as the usual scoop but with strong midbass performens in addition :)

The frontloaded application seems to be capable to run up to 300hz without any issues. :bouncy:





Please excuse me for this silly question;
Do I interpretate the simulation of the frontloaded JBL 2226h right!?
Will it produce 101db @ 50hz with 1watt input at 1meter distance...? :help:



I wish everyone of you an enjoyable weekend!!
All the best,
Olaf

[Hoerninger]

The frontloaded application seems to be capable to run up to 300hz without any issues. :bouncy:

It seems to be, at least the simulation shows it. The mass of the cone is relatively low to support this.

Care for the bends in a folded horn.

A horn is no sausage!

A good horn is straight - or there are reflectors,which reflect(!) the sound to the mouth and not backwards. A curved bend will produce unpredictable cancellations at the higher frequencies.
Dr.Bruce Edgar has made some investigations which are published in Speaker Builder 3/93 p.13.
A legalized copy is at Volvotreters site with "The Monolith Horn, page 2":
http://www.volvotreter.de/dl-section.htm
And Electro Voice patented something regarding reflections in 90 degrees bends.

The California horn has reflectors and they are angled the right way. It delivers far more than 300 Hz with a light cone.


Will it produce 101db @ 50hz with 1watt input at 1meter distance...? :help:
Oh ja! That's the theorie - place another speaker aside and you will experience it :) . But due to the low distortions the horn will not sound "loud".
I am shure you have read the sound impression regarding the Paragon XXL.
____________
Peter

[hmolwitz]

If you are looking for that last octave outdoors, with modest power, you really need a dedicated sub horn.
Steve Schell built this http://audioheritage.org/vbulletin/showthread.php?t=16913&highlight=big

Folds and bends are way less critical in a sub horn due to the wavelengths involved.

I built a similar compression loaded sub horn, and found it very effective at producing substantial bass for a modest investment in chipboard. I used a pair of Altec 3156 to drive mine as they were available.
Harry

[originaltubino]

Same horn with JBL 2226H but front loaded and standing in a corner.
The back chamber is choosen with 55 l.
The volume between cone and throat is reduced from ca 34 l to 3 l.

The grey graph showes the result for 2Pi.

This is very very interesting to me. I have a pair of 2226 I'd like to use in a 3-way. I've got tractrix-horn loading from 200-800, and am looking for horn-loading below that. Would you please share the dimensions of the horn to yield that graph? Or if it's easier, perhaps you could share the Hornresp file? I can PM my email address. I'm a total novice with hornresp, but I think I have enough determination to learn what I need from it.

[subwoof]

The JBL front loaded horns do NO benefit below 100Hz...

The rear loaded horns DO.

Size matters and the basics of physics do too.

The length, mouth size and flare cannot be mitigated...

read read read

[Hoerninger]

Would you please share the dimensions of the horn to yield that graph? Or if it's easier, perhaps you could share the Hornresp file?

This horn does not exist. It is a simulation to compare a frontloaded horn with a backloaded horn.
The ideal horn dimensions are those of the 4530 simulation (post #19).
The throat chamber volume Vtc is changed from 34000 cm^3 to 3000 cm^3 with a throat chamber area Atc = 880 cm^2.
The back chamber is choosen with Vrc = 55 liter and a depth of Lrc = 20 cm.
Due to the increased volume this simulated horn will be slightly bigger than the JBL 4530.
Additionally the horn needs a new folding! This is not difficulty but VERY time consuming until all dimensions fit well. And it is completely DIY, there are no experiences so far, it is completely on your own risk.

Btw have you noticed post no.11?

It is easier to build something you can rely on. I can fullheartedly recommend this horn (http://audioheritage.org/vbulletin/showthread.php?t=11909&highlight=xxl), I have built, tested and stressed it. It works fine. Four of them standing freely on a floor made the helicopters from "Ride of the Valkyre" in the film "Apokalypse Now" more than alive.
The dimensions are in such a way that it is not very neat for a living room in case WAF is of importance. The only restriction for me has been that it fits into the elevator.
____________
Peter

[Hoerninger]

If you are looking for that last octave outdoors, with modest power, you really need a dedicated sub horn.
Steve Schell built this http://audioheritage.org/vbulletin/showthread.php?t=16913&highlight=big

Folds and bends are way less critical in a sub horn due to the wavelengths involved.

This is quite a different animal!
I have been fascinated by this design and it inspired me to another simulation (http://audioheritage.org/vbulletin/showthread.php?t=14848). Luckily Steve Schell chimed in. He said " ... beginning to fall by 80Hz.", which indicates, that bending has a restrictive influence on the upper limit.


Folds and bends are way less critical in a sub horn due to the wavelengths involved.
Fully accepted. The thread starter Dr.db demanded "from 40hz up to 150hz " at the beginning but now he seems to be taken with 40Hz to 300 Hz.
For 300 Hz you should care for the bends IMHO.
____________
Peter

[Dr.db]

@hmolwitz (http://www.audioheritage.org/vbulletin/member.php?u=2549): Thanks for the link!! :)


@subwoof (http://www.audioheritage.org/vbulletin/member.php?u=285): You mean the scoops and original frontloaded JBL`s?
Usually frontloaded horns (like the California) should be able to produce below 100hz... If the hornlengh is bout 2meters... right? Or did I get you wrong?


@Hoerninger (http://www.audioheritage.org/vbulletin/member.php?u=2191): 150hz is enough, I just said it would be able to even handle 300hz.... for those who need that.

[OLDGEN]

i have loaded JBL D130 into my 4520 (http://www.stageaccompany.com/vintage/docs/4520s-4495s.pdf)
and bass is terrible, with my tube amplifiers, with SE or PushPull.

[louped garouv]

i have loaded JBL D130 into my 4520 (http://www.stageaccompany.com/vintage/docs/4520s-4495s.pdf)
and bass is terrible, with my tube amplifiers, with SE or PushPull.


you should have a very good mid bass though, right?
just missing the lower bass extension?

[OLDGEN]

my measurement is my ear, and now I feel I have enougt bass, low-mid, etc.:bouncy:

anyway tomorrow I will check with my soundgenerator

[pos]

i have loaded JBL D130 into my 4520 (http://www.stageaccompany.com/vintage/docs/4520s-4495s.pdf)
and bass is terrible, with my tube amplifiers, with SE or PushPull.

you should have a very good mid bass though, right?
just missing the lower bass extension?

I think this is a language barrier problem with the word "terrible":
For example in french you would use "terrible" to mean tremendous or fantastic. Quite different from the english meaning ;)
I don't know where Olden is from but I guess the meaning is the same in his country, as he seems satisfied with the bass he gets.

Buy the way Oldgen, where did all your UREI monitors go?

[hjames]

I think this is a language barrier problem with the word "terrible":
For example in french you would use "terrible" to mean tremendous or fantastic. Quite different from the english meaning ;)
I don't know where Olden is from but I guess the meaning is the same in his country, as he seems satisfied with the bass he gets.

Buy the way Oldgen, where did all your UREI monitors go?

So - he actually means "terrific" (GOOD) not "terrible" (BAD):applaud:

No flames meant - just wading in the waters of language issues ...

[OLDGEN]

sorry for my mistake.

[jcrobso]

i have loaded JBL D130 into my 4520 (http://www.stageaccompany.com/vintage/docs/4520s-4495s.pdf)
and bass is terrible, with my tube amplifiers, with SE or PushPull.

D140F or other JBL bass drivers would work better. John

[OLDGEN]

I have JBL 4xD140 and 4xD130B too, I am plaining to try them.

[louped garouv]

I think this is a language barrier problem with the word "terrible":
For example in french you would use "terrible" to mean tremendous or fantastic. Quite different from the english meaning ;)


sorry for my mistake.


ah. makes perfect sense now...

[m8o]

Not that this thread really needs this (a lot of very well informed folks here), but some really good info & pertinent "rules of thumb" & formulas under here
http://www.diyaudio.com/wiki/index.php?action=find&find=Bass+Horn+FAQ
especially the FAQ.

[Dr.db]

Thanks all of yous!!

Nice to read this.... Currently Im too busy to start buidling.. and still Im not shure wich one it will be :)



Regards,
Olaf

[paragon]

Measured with HiFish AC at 2.5 m distance where i hear.
4530 with 2205A Bass, 2441 with 2397, 2402 and 2405.

[OLDGEN]

D140F or other JBL bass drivers would work better. John

you have right!:banghead:
I have four JBL D130B (old from the years 50') they were not good in the 4520, and after I have changed for my 4xE-140, and the bass is amazing:bouncy:
I have 4xD140, but they need some reapir, and after I'll try.

[paragon]

Ich hätte die "Rutsche" weiter nach oben gezogen damit man die Verstärkungsleisten nicht mehr sieht.
Außerdem hätte ich die E140 mehr vermittelt, damit sie optisch schön symetrisch sind. Und die Kugelecken müssen weg. Ansonsten hätte ich die auch gern bei mir zuhause !:applaud:Super !
Vieleicht kann das jemand übersetzen ?

[OLDGEN]

Ich hätte die "Rutsche" weiter nach oben gezogen damit man die Verstärkungsleisten nicht mehr sieht.
Außerdem hätte ich die E140 mehr vermittelt, damit sie optisch schön symetrisch sind. Und die Kugelecken müssen weg. Ansonsten hätte ich die auch gern bei mir zuhause !:applaud:Super !
Vieleicht kann das jemand übersetzen ?

I would have " Rutsche" far upward pulled thereby one the reinforcement borders any longer does not see. In addition I would more have obtained the E140, so that they are optically beautifully symetrisch. And the ball corners must away. Otherwise I would have also gladly with me at home! Super! Perhaps can that translate someone?

the corners are very usefull when I change the speakers, minimum 5x in a week:blah: my backside is not happy with this moving-turning job:banghead:
if you have any idea to try some woofer, I am interesting:bouncy:

[paragon]

Good translation.;) Rutsche is shute or shoot or skid...
In my 4530 i used a Becker 915 A 16, JBL 2205A and JBL K145.
There is no difference i can hear in bass response use the 2205 or K145.
But there was a great difference between the Becker and the JBL, because the Becker had a high Qts. So, there was more upper Bass with the (very cheap) Becker driver.

[OLDGEN]

D140F or other JBL bass drivers would work better. John

YOU HAVE RIGHT!!
The K 140 is better choice
here is my other SCOOP, installed with 4 X JBL K 140, I like these new toys:-) I ma using with my MINI SE 2x2 watts Tube amplifier
http://tubeguru.hu/audio_tube_amplifier_SE/%22GREEN%22_MINI_Project.html

[Lee in Montreal]

What are the main differences between the K140, and the 2205 and 2225 for which the 4520 were designed? I run my 4530s with 2225s. If I had the room, I would use a pair of 4520s with 2225s.

[Fangio]

Good translation.;) Rutsche is..
(Bass-) Rutsche(n) = Scoop(s), both nicknames for the same enclosure type although the initial meaning of both words is somewhat different.


What are the main differences between the K140, and the 2205 and 2225 for which the 4520 were designed? I run my 4530s with 2225s. If I had the room, I would use a pair of 4520s with 2225s. K140 & 2205A were using alnico magnets, 2205H & 2225H have the later ferrite counterpart. In my understanding the K140 was designed for the musical instrument line, and not intended for playback.

Depends on your goal – for restoration, and for the sake of originality of vintage scoops I'd try to find and use the 2205A. The 2225H (or it’s successor 2226H) are the later, further developed woofers, they both will handle significantly more power.

[paragon]

Lee,

There is no difference in bass response. You may use all this drivers. Sound is very similar.
I use the K145 and compared it to the 2205. No difference.

Hallo Florian, wie gehts ?

Eckhard

[Fangio]

Gut, danke der Nachfrage. ;)

Some data yet, for comparison.

[Lee in Montreal]

Thanks Fangio for the clear chart.

BTW Isn't the K140 a guitar amplifier driver with pronounced upper mids?

[paragon]

Yes it is, but if you use it as a bass driver with max. crossover at 800 Hz there is no difference compared to the other drivers.:)