In words of one syllable......

[Gordon Steadman]

.......I have no knowledge whatsoever on technical matters. I just bung things in boxes and see if they work!!:doh:

My home made speakers using Celestion HF1300 and Kef B200 sound great. Superb clarity and a deep controlled bass.

However, there is an obvious mismatch in sensitivity between the two drivers and the treble needs reducing in level.

Can someone give me a simple guide to adding some resistance to the tweeter please. I assume I might have to play with the values but I have no wish to mess it up by sucking and seeing in this case.

Ta muchly.

[Barry]

To be able to help you Gordon, we would need to know the details of the crossover network you have used. You have used a crossover haven't you?

[Gordon Steadman]

To be able to help you Gordon, we would need to know the details of the crossover network you have used. You have used a crossover haven't you?

Yes indeedy,

Its a standard Celestion 15 crossover. I have just replaced the Celestion 8" with the B200

[walpurgis]

We've been here before Gordon and I offered some comments.

However, the Ditton 15 version of the HF1300 tweeter is an 8 ohm unit (despite the 4 to 8 ohm rating of the whole speaker). I'd suggest that if you are happy with the overall sound and just want a bit of treble cut, you look on eBay for a pair of 8 ohm 'L'' pad attenuators, which will do the job.

I'm not surprised actually, the HF 1300 has a sensitivity of over 90db and the B200 is around 86db.

[Rare Bird]

Could you work around part of the IMF 'TSL80' crossover, you could then even add the Coles '4001' ST..

[Gordon Steadman]

We've been here before Gordon and I offered some comments.

However, the Ditton 15 version of the HF1300 tweeter is an 8 ohm unit (despite the 4 to 8 ohm rating of the whole speaker). I'd suggest that if you are happy with the overall sound and just want a bit of treble cut, you look on eBay for a pair of 8 ohm 'L'' pad attenuators, which will do the job.

I'm not surprised actually, the HF 1300 has a sensitivity of over 90db and the B200 is around 86db.

Indeed, but at the time, I was carried away with the wonder of my great achievement and was not exactly over critical of the result:lol:

I did check the L pads and at about £17 for each speaker compared with a few pence for some resistors, it seemed a bit steep.

I can solder OK so a guide on values would be a starting point.

[Gordon Steadman]

Could you work around part of the IMF 'TSL80' crossover, you could then even add the Coles '4001' ST..

I tried the Coles in the distant past and was unconvinced!! Cloth ears I expect.

I don't really need to spend out too much on these speakers. I am told that the relevant funds have already been allocated elsewhere:(

[walpurgis]

I tried the Coles in the distant past and was unconvinced!! Cloth ears I expect.

I don't really need to spend out too much on these speakers. I am told that the relevant funds have already been allocated elsewhere:(

The Coles is a horrible sounding unit. It was used a lot because it was cheap and usually covered a small part of the audio bandwidth where its shortcomings are harder to detect. In comparison, the Celestion HF2000 is wonderful, but now expensive and only available second hand (Rogers chose it over the Coles unit in their Export Monitor to great effect). The KEF T27 works very well as a supertweeter and is rather cheaper, but used prices are going up. Any good quality 8 ohm tweeter with a response extending to say 20kHz or above should work, plenty about second hand. If you aim for a sensitivity of around 90db, the filter will bring that down to somewhere around the db output of the main speaker setup.

If you are going to add a supertweeter, remember that the output from the HF1300 cuts off dead at just above 13kHz and you'd need to bring the supertweeter in with a very steep curve at that point. 3rd order filter at least.

I've attached a link (below) to a site that will give you some useful component values for filters and also 'L' pad circuits. I think a cut in tweeter output of about 6db is what you may be aiming for. A 3db reduction would be hardly noticeable.

http://ccs.exl.info/calc_cr.html

[Gordon Steadman]

The Coles is a horrible sounding unit. It was used a lot because it was cheap and usually covered a small part of the audio bandwidth where its shortcomings are harder to detect. In comparison, the Celestion HF2000 is wonderful, but now expensive and only available second hand (Rogers chose it over the Coles unit in their Export Monitor to great effect). The KEF T27 works very well as a supertweeter and is rather cheaper, but used prices are going up. Any good quality 8 ohm tweeter with a response extending to say 20kHz or above should work, plenty about second hand. If you aim for a sensitivity of around 90db, the filter will bring that down to somewhere around the db output of the main speaker setup.

If you are going to add a supertweeter, remember that the output from the HF1300 cuts off dead at just above 13kHz and you'd need to bring the supertweeter in with a very steep curve at that point. 3rd order filter at least.

I've attached a link (below) to a site that will give you some useful component values for filters and also 'L' pad circuits. I think a cut in tweeter output of about 6db is what you may be aiming for. A 3db reduction would be hardly noticeable.

http://ccs.exl.info/calc_cr.html

Thanks Geoff,

That is one useful site although they have changed the link, it redirects OK. 4ohms in series and 8 in parallel is what it says so thats what I will try first.

I have a good pair of T27s although they are doing service with the Celestion 8" in another pair of speakers. Might try it though at some stage but that pair have the most fantastic clarity in the middle and top end that I am loath to take them apart. The bass is another matter but we can't have everything no, can we?

Thanks again for your help.