I agree that gpapag's offer of the Bailey 1972 TL design is a sound suggestion, even if it subsequently transpires that onkyponk is considering seven 3foot high cabinets.
My point really was a gentle reminder that from time to time, simple, specific questions can divert off into esoteric and very confusing discussions along the lines of how many angels can dance on the head of a pin. Where an enthusiastic novice asks a question, baffling them with such discussions will only convince them that "Here be dragons, keep out!". I know have been (and unfortunately still am) there.
For example; some time ago, I started a thread about using a pair of Kef B200s in a sub-woofer which led to the entirely reasonable and helpful suggestion that I should look at the Fried Model H. However I also got responses to the effect that "The huge 15mH aircored coils are totally unnecessary. Iron cored inductors with enough power handling would be fine." and also that I should Bi-Amp. Despite asking for clarification of these observations, I am none the wiser.
I entirely understand that there are some VERY knowledgeable people on this forum and that they may justifiably lack the inclination or patience to educate those less informed or experienced than themselves, I just wish that they would realise that some of their responses can come across as egotistical, patronising and effectively discouraging to someone who would like to learn.
Rant over - sorry 🙁
ps - Thanks Colin, Keilau and others who I can't think of at present, the comments above DEFINITELY don't apply to you 😉
Hi,
The issues are covered in that thread. The monster aircoils
are unnecessary, and it is pointed out the passive sub will
only match the model H speakers in correct level matching,
it won't match a set of LS3/5A clones, and many others.
All passive subs have this problem, they much be matched
to the speakers, whilst going active is far more flexible.
Its so sensible further discussion is not really needed,
given the inflexibility and cost of passive sub x/o's.
rgds, sreten.
Passive and active crossovers are essentially the same in the end, and both can be used to achieve any response. There could be a number of secondary concerns, such as ease in working with them, cost, weight/size/power, choice of amps etc.
Surely a very significant practical problem with long fibre wool is positioning it precisely and having it maintain its position over time? You provide a link to "Airtex high density urethane foam" available from Jo-Ann Fabrics, this link actually refers to Air-Lite foam which is I assume the same thing? Air-Tex foam is available through Amazon in the UK.
You also suggest that a substitute crossover should be readily available from Falcon Acoustics - I may have picked up entirely the wrong end of the stick but I understood that onkyponk was looking at using the B139s in a sub-woofer? So far as I can see, Falcon do not offer any suitable crossover. This then leads to the idea that onkyponk would have to locate and build from scratch a suitable crossover design - e.g. the left hand (B139) side of the Radford three way cross-over. At this point, things get very, very confusing - as I learnt when I wanted to do something similar with a pair of Kef B200s - essentially proposing that one should either use active crossovers or Bi-Amp 🙁
Incidentally, as an aside (and reluctantly off-topic) in relation to the Radford three way cross-over, how are the 0dB, +1dB & +2dB options on the B110 & T27 wired up? I assume that they rely on a switch connecting them to the +ve line at the top and skipping the related resistors?
You made many very good points. Your experience in the UK scene would be more helpful to onkyponk.
Early on, I was told to get the long fiber wool cleaned and carded. Trying to clean raw long fiber wool at home was messy and would get me on the wrong side of every family member (it smells). I toke the advice. The processing cost 2 times more than the raw wool itself, but it was well worth it. It was very easy to spread the carded wool inside the cabinet. I checked them and it never saged over 30 plus years. (The woolen mill told me that they use the same process for wool comforters. The carded wool did not lose its fluffiness over time.) I am in the middle of rebuilding my Baileys. The rubber surround in the original woofer lost resiliance and doesn't work anymore. I am re-using the old wool.
I suspect that it is easier to get Long fiber wool in UK than in the US. Look for a woolen mill who provides the cleaning and carding service.
I got the Jo-Ann Fabrics link from JimPA over at AudioKarma and just passed it on. I have no first hand experience using the foam to stuff a TL. Jim said to get midium density and fine open cell for this purpose. Glad to hear that you can get suitable substitute in UK.
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I hope there is no rule against posting on old threads here. If so, apologies in advance...
My first foray into TL was construction of a pair Radford S90's. Wonderful sound back then but then had to be mobile (they were big and heavy) so I changed hobbies.
Now, doing the nostalgia trip. I am hoping for feedback on this idea: A closed transmission line at 1/2 wavelength of 110Hz with a B139 driver at the front and a B139 resonator at the end. The planned bandwith is 110 Hz to 880 Hz with external active crossovers and tri-amping Quad 405's. I plan to use B110's at the mid bass drivers to 3 kHz. The HF units are TBA.
Now I will put on my peril sensitive sunglasses and wait....
My first foray into TL was construction of a pair Radford S90's. Wonderful sound back then but then had to be mobile (they were big and heavy) so I changed hobbies.
Now, doing the nostalgia trip. I am hoping for feedback on this idea: A closed transmission line at 1/2 wavelength of 110Hz with a B139 driver at the front and a B139 resonator at the end. The planned bandwith is 110 Hz to 880 Hz with external active crossovers and tri-amping Quad 405's. I plan to use B110's at the mid bass drivers to 3 kHz. The HF units are TBA.
Now I will put on my peril sensitive sunglasses and wait....