question for Rob about TN-1220

[golfhack]

Hi Rob,

I noticed you said that you have a pair of TN-1220's. I am considering purchasing a pair as well and was hoping you could answer some questions for me. First and probably most importantly is do you have them standing upright? The reason why I am asking is because I notice that they are extremely lightweight and that kind of concerns me as to whether they would be easy to tip over. Secondly, if they are laying down do you have them facing each other and wired out of phase so as to work in a push-pull fashion. According to a forum discussion I read hosted by Dr. Hsu, he said by doing this the even ordered harmonics would cancel each other out resulting in overall lower distortion. One last question Rob, if I may: according to Tom V., when answering a question from someone about the difference in using multiple smaller drivers as compared to using one larger driver (this was found in the notorious thread here at audioholics where Peter and Tom were present) when comparing frequency EXTENSION, Tom stated that it comes down to the amount of air that is displaced. But isn't that only referring to spl levels and not necessarily frequency extension? In other words, I was always under the impression that if you add two 10" drivers, your overall spl will gain by approx. 6 dB, but you would not gain anything in extension. Perhaps Tom misread the question, or maybe I'm just thinking wrong? Thanks for your time Rob.

 

[Rob Babcock]

No, you don't have to stand them up. In fact, Dr Hsu told me a lot of people use them lying on their side, and they're easier to hide if you don't like the look. If you have carpet you'll find they're not as tippy as they look like they would be, but if you're worried (or have pets/kids) go ahead and lay them down.

Dr Hsu also advised me that it's not worth doing the push/pull thing. That must be a holdover on the web site because he himself told me not to bother.

Adding multiple subs may not give you added extention per se, but you do get more output at all freqs. The TN-1220 is tuned & EQ'd for 18 hz, and with a pair you'll get staggering output down to the lower reaches of the largest pipe organ fundamentals. Perhaps there are subs that can go louder and lower, but I get over 115 dB @ 20 hz in room (perhaps I could go louder, but I simply don't have the nerves to try!).

You might want to consult with Hsu Research before you buy, though- they claim their new "turbo" port will allow a single box to equal a pair of TN-1220's...that seems to strain credulity, but perhaps it's so. If that's the case you may want to hold out for a pair of them.

All told, my Hsu's are about the only thing in my system that I probably would't change if I had a million dollars! I've toyed with the idea of adding another pair, even though it would be absurb overkill- maybe when I win the lottery!

 

[Rob Babcock]

Hi Rob,

One last question Rob, if I may: according to Tom V., when answering a question from someone about the difference in using multiple smaller drivers as compared to using one larger driver (this was found in the notorious thread here at audioholics where Peter and Tom were present) when comparing frequency EXTENSION, Tom stated that it comes down to the amount of air that is displaced. But isn't that only referring to spl levels and not necessarily frequency extension? In other words, I was always under the impression that if you add two 10" drivers, your overall spl will gain by approx. 6 dB, but you would not gain anything in extension. Perhaps Tom misread the question, or maybe I'm just thinking wrong? Thanks for your time Rob.

To clarify, what he says is true. The "amount of air" displaced could describe the extention or the volume, but how low it will play is determined by the T/S parameters of the driver and the enclosure. You can tune a box lower at the expense of volume by changing the port length/size, or vice versa (SVS does this with their 3 sizes of CS subs- each is tuned to a different freq).

 

[Rock&Roll Ninja]

Maybe they'll make a "turbo" kit for the cylinders, then we can get 115db at 12Hz!