Horn Pondering.

[walpurgis]

Just mulling ideas over.

Has anybody got an idea if an eighth wavelength constant width back loaded folded horn speaker might work? I've built successful 1/4 wave units in the past.

I'm not referring to the Troels Gravesen types, which have a restricted exit and appear to work as some sort of acoustic column.

I know 1/8 wavelength transmission lines can work well enough.

[southall-1998_mk2]

Hope you are well, Geoff.

What amp are you currently using?

S.

[walpurgis]

Hope you are well, Geoff.

What amp are you currently using?

S.

Hi Shane, I'm fine mate (relatively :)).

I've got a variety of amps, but keep going back to the NAD 3130. Cheap but amazingly good.

[southall-1998_mk2]

NAD has produced some great gear. Have fun!

S.

[Lawrence001]

Just mulling ideas over.

Has anybody got an idea if an eighth wavelength constant width back loaded folded horn speaker might work? I've built successful 1/4 wave units in the past.

I'm not referring to the Troels Gravesen types, which have a restricted exit and appear to work as some sort of acoustic column.

I know 1/8 wavelength transmission lines can work well enough.

With your B&W DM2a's [emoji2]

I'm not aware of the advantages of a quarter wave rear horn loading, is it a "thing"?

[walpurgis]

I'm not aware of the advantages of a quarter wave rear horn loading, is it a "thing"?

Back loaded quarter wave horns have been in use for a lifetime, as per Lowther. Bass dynamics with a BLH can be spectacular, if limited in depth.

I did ask about eighth wavelength. I think there may be something to it, the energy at the horn mouth is halved for each halving of line length, but as with eighth wavelength transmission lines, there is still a proportion of positive pulse.

Incidentally, IMF and PMC have made truncated transmission line speakers which appear to have line lengths as short as 1/16th wavelength.

[Lawrence001]

Those will be the bookshelf ones? I guess any length line may help to reduce potential phase issues of a simple port, quarter wave is just the ideal one.

[walpurgis]

I suppose a half wavelength transmission line would be the ideal, but it would be enormous and would need a lot of internal damping to avoid a big bass hump.

(I'm just visualising the size it might need to be for 15 inch Tannoys :lol:)

[Macca]

I'm not keen on any type of horn-loading.

Not sure why transmission lines are being brought up, since they're not the same thing? Plus transmission line loudspeakers are rarely true transmission lines.

This is one of those 'If you want to go to Dublin I wouldn't start from here' situations :)

I've always thought best bass loading was a good big driver in a large sealed cab. Not optimal as nothing is but I reckon it is the best compromise.

[bumpy]

I have owned Lowther Acoustas, Lowther Medallions and Hedlund horns, do these qualify in what you are looking at. I have also had at home for evaluation Impulse H6s and Impulse H2s.

I think the drivers are at least as important as the cabinets.

[Lawrence001]

I have owned Lowther Acoustas, Lowther Medallions and Hedlund horns, do these qualify in what you are looking at. I have also had at home for evaluation Impulse H6s and Impulse H2s.

I think the drivers are at least as important as the cabinets.Absolutely. Do you remember the guy on eBay who used to put car speakers in transmission line cabinets and charge loads for them?

[walpurgis]

Absolutely. Do you remember the guy on eBay who used to put car speakers in transmission line cabinets and charge loads for them?

Car speakers may a good choice for situations that need a driver with decent self damping. I don't recall the seller though.

As far as I can see, car speakers are no better or worse than others, as long as you don't mind the usual 4 ohm impedance.

[walpurgis]

Not sure why transmission lines are being brought up, since they're not the same thing

Open ended TLs and BL horns both rely on the line length.

[Macca]

Absolutely. Do you remember the guy on eBay who used to put car speakers in transmission line cabinets and charge loads for them?

I do, I think he used 4-way coaxial drivers intended for cars. Can't recall the make of them. The design was based on the Capel transmission line. You used to be able to buy the instructions to build it in those little books they would sell in electronics shops. Except Capel's design used a single driver, an EMI elliptical unit from memory.

[Lawrence001]

I thought it was this guy but he seems to use proper hifi drivers in these ones

http://www.claer.co.uk/complete/claer43peerlessfountek/

[Macca]

I thought it was this guy but he seems to use proper hifi drivers in these ones

http://www.claer.co.uk/complete/claer43peerlessfountek/

Not the one I was thinking of. His speakers had a mahogany finish and the drivers were gold coloured. Might be the same bloke but he's moved on to different designs I suppose.

[Lawrence001]

Not the one I was thinking of. His speakers had a mahogany finish and the drivers were gold coloured. Might be the same bloke but he's moved on to different designs I suppose.No you may be right, this guy might have used better drivers but in very unconventional cabinets.

[VanDerGraaf]

https://i.ebayimg.com/images/a/(KGrHqZHJEME-nGtZjckBPqo6h(pPg~~/s-l1600.jpg


Is this the thing you're thinking of, chaps?

Sorry about the stupid image size.

[Ali Tait]

Yep that’s the chap.

[VanDerGraaf]

Always wondered if anyone has actually heard a pair? The adverts are weird, seeming to promise very deep bass, and then in the next paragraph saying that the vass is not too audible and needs to be boosted.

To be fair bass is not touted as the raison d'etre of the speaker.