Celestion HF1300

[Gordon Steadman]

Hi folks,

Does anyone know the lowest safe frequency that the HF1300 will handle? I want to use the 15ohm version in a project that demands somewhat lower crossover than the usual 3500htz.

Ta.

[Mr Kipling]

No.


I'm only being honest, Gordy.

[Gordon Steadman]

No.


I'm only being honest, Gordy.

Thanks.

How can one argue with honesty? Such a rare commodity these days:)

[Mr Kipling]

You're a gent, Gordy, and no mistaken.

You'll have to wait till Guru Geoff turns up.

[walpurgis]

The HF1300 was crossed over (a pair of units) at around 2kHz in the Celestion Ditton 25 speaker if I recall. It depends on how much power you are expecting to use, but I'd suggest a minimum roll-in slope of 12db/oct or maybe better 18db/oct in order to avoid the tweeter having to handle larger amplitudes and of course to keep the tweeter's lowest resonance out of the picture. I have used an HF1300 from 2kHz without problems.

[Gordon Steadman]

The HF1300 was crossed over (a pair of units) at around 2kHz in the Celestion Ditton 25 speaker if I recall. It depends on how much power you are expecting to use, but I'd suggest a minimum roll-in slope of 12db/oct or maybe better 18db/oct in order to avoid the tweeter having to handle larger amplitudes and of course to keep the tweeter's lowest resonance out of the picture. I have used an HF1300 from 2kHz without problems.

Thanks Geoff,

That is exactly what I was wanting to hear. The existing crossover is at 2khz and its just a test so I won't be putting much power through it.

[DSJR]

There's a resonance at around 3.5k that the steep filtering as used by Spendor helped minimise. Good as it is in its passband, I'd suggest not using this ancient tweeter outside its 'envelope,' as it won't be as kind to this as most modern drivers.

Plots of BC1 below

http://i132.photobucket.com/albums/q8/DSJR_photos/EarlyBC1reviewpt2responsesonly.jpg (http://s132.photobucket.com/user/DSJR_photos/media/EarlyBC1reviewpt2responsesonly.jpg.html)

[Gordon Steadman]

There's a resonance at around 3.5k that the steep filtering as used by Spendor helped minimise. Good as it is in its passband, I'd suggest not using this ancient tweeter outside its 'envelope,' as it won't be as kind to this as most modern drivers.

Plots of BC1 below

http://i132.photobucket.com/albums/q8/DSJR_photos/EarlyBC1reviewpt2responsesonly.jpg (http://s132.photobucket.com/user/DSJR_photos/media/EarlyBC1reviewpt2responsesonly.jpg.html)

Thanks David,

I just ran a very quick test to check that a sort of metallic honking I was getting was the tweeter or midrange. The output from the HF1300 was just about identical to the existing tweeter so the culprit may well be the midrange as I know the Celestion is sweet and clear. More playing to come.

[walpurgis]

The HF1300 does have a distinctive minor colouration. I think it may be a cavity effect from the back enclosure, it's rather strange in that it comes to the fore more when paired with some bass/mid drivers than others. Having used the HF1300 in at least half a dozen home built speakers I've definitely noticed this.

[Reffc]

AFAIK, the HF1300 isn't at all happy to take its full power handling at anything under 3KHz and at 3kHz it was often used with an 18dB/Oct filter (as in the BC1). It has a high resonant frequency of around 1.6 to 1.7KHz and really ought not to be used below 3KHz. That resonance will be audible as distortion crossing over low (at say 2600Hz) unless a notch (L-C-R) filter is used the squash resonance amplitude and a steep filter used. I would certainly not be using it at anywhere close to 2KHz. Apart from anything else, you're likely to put way too much power through it this low down as well as it sounding pretty awful run this low.


However, the HF1300 was used in a pair (per cabinet) in the LS 5/1 and run with both used at lower power between resonance and 3KHz with one being rolled off to leave the other handling HF above 3KHz in full power and this is possibly the same configuration used by Celestion? In terms of using it as a single unit crossed over low, my advice would be not to consider that of this tweeter. It's asking too much of it.

[DSJR]

I think the Ditton 25 used two to increase the levels to match the 12" bass divers (from memory). The horizontal disposition did all manner of things to dispersion so I suspect these were best used in far-field conditions, where the Ditton 44 and 551 would suit smaller rooms better, as do the 66's and 661's in actual fact.

Even Alan Shaw has commented on the good quality of the HF1300 when used within its safe region. I think the original design was as a sort-of 1950's wall mounted intercom driver in submarines or something :scratch:

[walpurgis]

Tannoy, Fane and Coles produced very similar tweeters. Each with phenolic diaphragms and phase correction plates as per HF1300. In fact the Coles (3000 I think the model was) looked virtually identical. I've used the Fane (model 301), which dates from the late sixties, it's a nice unit. The Tannoy tweeter was in the Audiometric two way system that looked like a Chatsworth cabinet, again late sixties.

[Reffc]

I think the Ditton 25 used two to increase the levels to match the 12" bass divers (from memory). The horizontal disposition did all manner of things to dispersion so I suspect these were best used in far-field conditions, where the Ditton 44 and 551 would suit smaller rooms better, as do the 66's and 661's in actual fact.

Even Alan Shaw has commented on the good quality of the HF1300 when used within its safe region. I think the original design was as a sort-of 1950's wall mounted intercom driver in submarines or something :scratch:

Yes, he has mentioned the HF1300, I think in the context of the LS5/1. The 5//1 mounted the tweeters one above the other, much the same as for the Ditton 25, but the Ditton offset them to lower the effects of edge diffraction whereas the 5/1 like other BBC designs I think relied on the grille/acoustic wool surrounds. The effects of mounting one above the other would give a similar off axis spread but the lobing pattern interference would have been interesting! The 25 used the configuration in much the same way as the others (two tweeters operating at 50% power draw each for the mid range and one rolled off steeply allowing the top one to carry on at full power draw above 3 to 3.5KHz). Why they didn't just use a conventional midrange unit I don't know.


Tannoy, Fane and Coles produced very similar tweeters. Each with phenolic diaphragms and phase correction plates as per HF1300. In fact the Coles (3000 I think the model was) looked virtually identical. I've used the Fane (model 301), which dates from the late sixties, it's a nice unit. The Tannoy tweeter was in the Audiometric two way system that looked like a Chatsworth cabinet, again late sixties.

Tannoy Audiometric:

http://i1140.photobucket.com/albums/n577/24pacman/5c366918-b618-4c17-a8bf-1a760eefc77d_zps1f13eaaa.jpg

LSU/HF/1: This is an interesting one as I believe that the Townsman speakers produced by Tannoy used these, purportedly as their Laboratory Series speakers. (Anecdotally as a relatively short production run for public domestic sales because the performance was better than the DCs of the day and therefore they couldn't have a cheaper but better speaker competing with the more expensive DCs!) and the response was reputedly far more accurate than the Dual concentric speakers. Highly collectable and sought after in the Far East. If you see a pair for reasonable money, it would be rude not to nab them!

Coles:

http://i1140.photobucket.com/albums/n577/24pacman/9f05c624-88a5-4c1a-b91f-5d676de84a14_zps6c7b777e.jpg


Fane:

http://i1140.photobucket.com/albums/n577/24pacman/fane301_zps06127c88.jpg

Can't say I've ever heard the Fane or Audiometric units. AFAIK the Fane used an Aluminium cone & ALNiCo magnet (Ref 1962 Hifi Year Book)

[walpurgis]

AFAIK the Fane used an Aluminium cone & ALNiCo magnet (Ref 1962 Hifi Year Book)

Well so it does. According to my 1965 Hi-Fi Year book. If that's correct of course. :)

(we could have a competition to see who's got the oldest and the most year books)

[Gordon Steadman]

A quick query for Geoff or any other wiz.

Being a clever fellow, I disconnected the crossover network from some homemade speakers as I want to use the HF1300s in another project and feel it best to keep the matching crossover.

I forgot to make a note of which wire goes where!!!:doh:

Am I right in assuming that the pass for the bass is a first order with just a coil to the bass unit and the pass to the tweeter is a second order with a coil and capacitor?? If so, the single lead from the larger coil is for the bass unit!!

Don't want to blow up the tweeter by being any dafter than usual.

[Reffc]

A quick query for Geoff or any other wiz.

Being a clever fellow, I disconnected the crossover network from some homemade speakers as I want to use the HF1300s in another project and feel it best to keep the matching crossover.

I forgot to make a note of which wire goes where!!!:doh:

Am I right in assuming that the pass for the bass is a first order with just a coil to the bass unit and the pass to the tweeter is a second order with a coil and capacitor?? If so, the single lead from the larger coil is for the bass unit!!

Don't want to blow up the tweeter by being any dafter than usual.

Hi Gordon

yes, it's more common to use a 6dB filter with the bass and 12dB with the tweeter so it sounds about right if the bass unit would use a 1st order and the tweeter would use the steeper slope, so the cap should be the first thing in series with the input positive rail and the coil would connect after the capacitor and shunt to ground (-ve rai) with the positive output for the tweeter coming from the positive rail after the cap and junction for the coil. The bass unit would have the positive input connected in series with one of the wires for the larger coil and the positive output from the other wire let of the coil. Bass -ve would be a straight connection between input and output.

[walpurgis]

Can you not just look at the other speaker? Or is that disconnected too? Although it does sound that your deductions about the crossover may be correct.

If it all goes BANG you'll know you were wrong! :)

Seriously, can you post a picture of the crossover?



Actually, I'm no "wiz". I've just messed about with an awful lot of equipment and have an idea of how most of it works.

[Gordon Steadman]

Can you not just look at the other speaker? Or is that disconnected too? Although it does sound that your deductions about the crossover may be correct.

If it all goes BANG you'll know you were wrong! :)

Seriously, can you post a picture of the crossover?



Actually, I'm no "wiz". I've just messed about with an awful lot of equipment and have an idea of how most of it works.

Pic attached. Judging from Paul's comments, it looks as though I'm right - thanks Paul. The second lead was attached to the right hand side of the big coil on the metal bar. Naturally, I disconnected both!!!

[walpurgis]

Looks like a Ditton 15 crossover. The large inductor is your bass filter. The series cap/parallel inductor are your HF side.

[Gordon Steadman]

Looks like a Ditton 15 crossover. The large inductor is your bass filter. The series cap/parallel inductor are your HF side.

Indeed it is.

Thanks chaps.:cool:

[spendorman]

You say that you are using the 15 Ohm version of the HF1300, but the Ditton 15 crossover is matched with a lower impedance HF1300.

If you are using the two 15 Ohm 1300's in parallel, that might work.

[Gordon Steadman]

You say that you are using the 15 Ohm version of the HF1300, but the Ditton 15 crossover is matched with a lower impedance HF1300.

Ah, yes indeed, I have three pairs of HF1300s, two of them are 8ohm and I realised that I would need to use one of those earlier this evening.

My wife will be pleased, the pair I'm thinking of using reside in her JBLs at the mo:eek:

[Mr Kipling]

Are you hoping she won't notice when you extricate them?

[spendorman]

I can't remember, but I have a feeling that the ones in the Ditton 15 are less than 8 Ohms impedance.

I like the HF1400, found in the B&W DM3 and a BBC design.

[Gordon Steadman]

Are you hoping she won't notice when you extricate them?

:)

They are sort of spare at the mo. I'll probably put the 15ohm ones in them anyway, just to fill the hole. Who knows, they may sound better with the wrong tweeter impedence, they are 'spare' for a good reason.

They are joint 5th out of six pairs of speakers, around the same ranking as the little Wharfdale Diamond 7 pros that I use on the Mac.

[Gordon Steadman]

I can't remember, but I have a feeling that the ones in the Ditton 15 are less than 8 Ohms impedance.

I like the HF1400, found in the B&W DM3 and a BBC design.

Ah, quite possibly, but the ones I will use actually came out of the Ditton 15s.

[Mr Kipling]

Oh. For a moment i thought there was going to be some skullduggery perpetrated, some dark night.

[walpurgis]

I can't remember, but I have a feeling that the ones in the Ditton 15 are less than 8 Ohms impedance.

I like the HF1400, found in the B&W DM3 and a BBC design.

The Ditton 15 speaker system is rated at 4 to 8 ohms. The tweeters are usually marked 4 ohms, but measure about 4 ohms DC, meaning that they are actually nearer a 6 ohm impedance load.

[spendorman]

The origin of the Celestion HF1300 may well be here, the GEC tweeter.

http://soundup.ru/images/stories/archive/Classic/speakers/gec-genalex-fr-bcs-1851-8-aluminum-cone-speaker-1852-tweeter/gec-genalex-fr-bcs-1851-8-cone-1852-tweeter-8.jpg

[spendorman]

More stuff here:

http://www.novacon.com.br/audiogecld6.htm

[Gordon Steadman]

Oh. For a moment i thought there was going to be some skullduggery perpetrated, some dark night.

Wouldn't never ever appen round ere guv.

[walpurgis]

The origin of the Celestion HF1300 may well be here, the GEC tweeter.

http://soundup.ru/images/stories/archive/Classic/speakers/gec-genalex-fr-bcs-1851-8-aluminum-cone-speaker-1852-tweeter/gec-genalex-fr-bcs-1851-8-cone-1852-tweeter-8.jpg

Yes, I remember those and the full range metal coned driver they did.