jonjin

Horn project - stupid questions

461 posts in this topic

For the resident experts,

Just collected my Altec 416s to go into a future Onken bass cabinets. It's recommended to cross-over at 550Hz.

What I'm confused about is which is more important in deciding the midhorn? The actual horn itself or the driver? Most driver maunfacturers I've seen (JBL, TAD) etc recommend crossing over at 600 Hz or 800 Hz. But is it okay to put them into horns that go below that (eg 270Hz) and expect them to be okay?

Sorry if the question is wrongly worded. If there's any websites I should read, let me know... this will hopefully be a long term project that will keep my idle fingers busy!

JJ
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[b]jonjin wrote: [/b][quote]For the resident experts,

Just collected my Altec 416s to go into a future Onken bass cabinets. It's recommended to cross-over at 550Hz.

What I'm confused about is which is more important in deciding the midhorn? The actual horn itself or the driver? Most driver manufacturers I've seen (JBL, TAD) etc recommend crossing over at 600 Hz or 800 Hz. But is it okay to put them into horns that go below that (eg 270Hz) and expect them to be okay?

Sorry if the question is wrongly worded. If there's any websites I should read, let me know... this will hopefully be a long term project that will keep my idle fingers busy!

JJ
[/quote]

Both horn and driver are important. Generally, as compression drivers are designed for high power PA use, at domestic power levels you can get away with playing them lower - at reduced power, so for every octave, de-rate by 50%. But...that doesn't mean they will sound any good playing lower.

As a rule of thumb, the driver should be crossed at least 0.7-1 octaves above Fc, the cut-off frequency of the horn. So, for example, a 500Hz horns you would need to cross at an absolute minimum of 800Hz or so, and 1kHz would be better. Below that the horn does not load the driver and diaphragm excursion increases sharply - this can cause damage. You will likely hear the diaphragm "clacking".

If you want to cross at 550Hz, you will need to put the driver on a 300Hz horn.


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JJ, also download a copy of hornresp and have a play:

[url]http://www.users.bigpond.com/dmcbean/[/url]
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[b]i_should_coco wrote: [/b][quote]JJ, also download a copy of hornresp and have a play:

[url=http://www.users.bigpond.com/dmcbean/]http://www.users.bigpond.com/dmcbean/[/url][/quote]

Thanks, I'll have a read when I'm at home... lots of things for me to learn. How are you getting on with your own project Pete?

JJ
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[b]jonjin wrote: [/b][quote][b]i_should_coco wrote: [/b][quote]JJ, also download a copy of hornresp and have a play:

[url=http://www.users.bigpond.com/dmcbean/]http://www.users.bigpond.com/dmcbean/[/url][/quote]

Thanks, I'll have a read when I'm at home... lots of things for me to learn. How are you getting on with your own project Pete?

JJ
[/quote]
Erm... :oops: Slowly... very slowly.... :?

Have sent some horn info to you e-mail as well.
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[b]jonjin wrote: [/b][quote]Okay, so I'll need a 300Hz horn. Any recommendations for driver?

JJ[/quote]
Vitavox S2 :D.

Depends how much you want to spend, really. At the more sensible end of the scale, JBL 2420s or LE85s perhaps?
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[b]i_should_coco wrote: [/b][quote][b]jonjin wrote: [/b][quote]Okay, so I'll need a 300Hz horn. Any recommendations for driver?

JJ[/quote]
Vitavox S2 :D.

Depends how much you want to spend, really. At the more sensible end of the scale, JBL 2420s or LE85s perhaps?
[/quote]
How much is a clean S2 these days? Prices still mental?
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[b]anubisgrau wrote: [/b][quote][b]i_should_coco wrote: [/b][quote][b]jonjin wrote: [/b][quote]Okay, so I'll need a 300Hz horn. Any recommendations for driver?

JJ[/quote]
Vitavox S2 :D.

Depends how much you want to spend, really. At the more sensible end of the scale, JBL 2420s or LE85s perhaps?
[/quote]
How much is a clean S2 these days? Prices still mental?[/quote]
Too much....
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hi JJ

the problem of S2 is not only the price, but you would need some patience to find a pair. They do not come up very often for sale at ebay. I have seen only 5 pairs in 2 years. The price today is about 1300 pounds. Hifi works has 3 units, but is asking 900 pounds per unit, which is above marketprice.

[url=http://www.hifiworks.co.uk/images_fullsize/s2.jpg]http://www.hifiworks.co.uk/images_fullsize/s2.jpg[/url]

Vitavox S3 does use the same diaphragm as S2, and seems to sound good as well, according to someone i know, that had both drivers. There is a pair at ebay for sale right now, and these do not go so expensive.

A other alternative is the Radian 950pb. I have compared it directly to S2, and it sounds wonderful. It is a 2" driver, goes lower, and higher than S2, and makes it suitable for 2way configuration. Used on a 65cm/27" round tractrix horn, crossed as low as 300hz, it sounds stunning, and no tweeter needed. Fc of this driver is 550hz. Many say, below Fc a driver has lots of distortion. Well, used with a few watts domestic use, i don't agree. It sounds very clean, no distortion at all.

As horn, the best is round LeCleac'h, tractrix, or CD Gueddes Waveguide, which however is not indicated , if you want to cross as low as 500hz.

If you decide to buy any Radian driver, i can recommend you a cheap source. Just mail me.

Angelo

[img]http://i307.photobucket.com/albums/nn281/AudioVoice/Figura1-1.jpg[/img]

[img]http://i307.photobucket.com/albums/nn281/AudioVoice/Figura1go.jpg[/img]


---------------------------------------------------------------
[url=http://www.flickr.com/photos/12312992@N07/page1/]my blog[/url]

[url=http://www.audiovoice-acoustics.com/forum/index.php]my forum[/url]
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i watched the ebay auction angelo mentioned - a pair of S3 with RH330 horns went for $1200, that's 600 quid. not bad, i would be tempted to build a pair of speakers fully designed for my listening room, although it seems that it all now comes together with my current speakers once i've got F3.

given the price of 1.5" tractrix horns from the german ebay seller pointed atby murray johnson, which gives an option to runvitavox drivers in a 2-way assembly,this would be still quitea reasonably priced product. some other time...:)
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Good to hear you are moving on and up JJ - if you've got the space to accomodate them you sure won't regret it. One observation I would add is that horns are (by definition) narrow band devices. There are also IME very few 15" cone drivers that can approach 5 octaves or more without compromise.

The more you can use the selected drive units within the scope of their linearity the better IME, and the less the end result will sound like a horn speaker.

In your case I would expect a 300hz tractrix to be crossed over to a JBL2405 or similar at 5khz to give preferable results - but then you are only really swapping one set of compromises (break up modes and non linearity) for another (comb filtering).

Good luck!
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..just found this thread.

Of course, an alternative to looking for a horn to go to 300hz (expensive and big), another option is looking for a bass solution that can be crossed over higher.


This leads to another question of course, which is whether you stick with a nice simple two way, or go 3, 4 or (bonkers now) 5 way.

Getting horns sounding right within a narrow bandwidth can lead to a big 4/5 way solution reminiscent of a set from "Space 1999"

If you still hanker for a more living room friendly solution I would look at bass solutions that give you more flexibility - or at least exploring the possibility. If you are able to look at ultimate sound and ultimate size, you can chuck that out of course and go with a massive 3-5 way horn system.




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It's all a learning process and information gathering at this stage. Realistically looking for a 3-way. I've already more or less set on the Onken bass system with Altec 416-8A Alnicos. They're BIG I know... these should realistically x-over at 550Hz but have output beyond that... we'll see.

These would be the dream...

[img]http://www.goodsoundclub.com/UserImages/ExperienceMusic@VSAC.jpg[/img]

Which horns are you using Bottleneck?

JJ
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Hi JonJin

I used to use Altec horns - I had a model called the Valencia, which had a sectional horn (4 vains) mated to a 15" Altec bass cone. I added a JBL 2405 tweeter over the top.

I am going for a build at the moment. It will be much the same as the Valencia's I had before, except with Tad bass and compression driver. A similar design however.

I much prefer to use a bass horn below the compression driver, but I have to be realistic concerning the amount of space I can provide a loudspeaker. A 15" in a ported cab is about as big as I want to live with in my moderately sized lounge.

pic here of my old Altecs. They had a beautiful solid wood cabinet - [url]http://img4011.photobox.co.uk/788120958848ff89e90d242b9633eaed3b5605452c279eaae0a01affd88c122f8d6f24e2.jpg[/url]


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