john's tb - power handling concerns

[dvdwmth]

Im building some speakers as a gift for my brother to use in his home surround set up. I was going to build the smallest of john's tang bands but even he raises power handling concerns. I dont know how loud these will be played.

Should I build a 1.5 way instead or will the single driver with a cap to filter bass be sufficient.

[GM]

With rare exception, all small diameter wide BW drivers have very limited linear excursion and not a whole lot of usable excursion before audible distortion becomes excessive. Considering how popular B*** HT systems are though, it appears many folks will tolerate a lot of it, but from a CYA POV, I would do a 1.5 on at least a ~8.63" wide (~500Hz F3) baffle.

Even then, it's going to be limited to ~90-95dB peak/m down low depending on how much distortion is acceptable, so forget getting anywhere near DD/DTS reference.

GM

[joensd]

I´ve played quite a lot now with the TB-W3-871S and yes, as nice as they sound they are very SPL-limited.
Mate them with a woofer or think about something bigger like the TB-W4-657S which will give you more bass and excursion.

There was a recent project as HT-satellites in K+T-magazine (germany) and they reported their good sound but they also wrote that you can use them as PC speakers if you move on to the next HT system....

[Zaph]

Originally posted by dvdwmth
Im building some speakers as a gift for my brother to use in his home surround set up. I was going to build the smallest of john's tang bands but even he raises power handling concerns. I dont know how loud these will be played.

Should I build a 1.5 way instead or will the single driver with a cap to filter bass be sufficient.

I've been a big fan of the TB 871's, but there's two things I've seen many others do but you'll never see me do. The first is put this driver in a vented enclosure. The enclosure requirements are too large, the tuning would be so high that there is substantial (and destructive) power handling issues below tuning, the Qts is too high, and as a direct result of that, the group delay at the tuning (which is right smack in the middle of the bass range) sounds terrible. I've tried it, it sucks.

But the second thing is to use two 871's in a 1.5 arrangement. Sure, you could do it and it would make sound, but why bother? If there are going to be two drivers in one enclosure, it's a wiser choice to pick two drivers that will expand the bandwidth and add power handling. Putting two 871's in a box does not help the bandwidth, and barely makes a difference in the power handling dept. The top end is still directional, and the bottom end still rolls off at about 160hz. Given the large Qts of the 871, putting two in an enclosure requires a large box too. In summary, all you gain is the neat appearance of having two 871's.

If output level is important, a better option would be a small two-way system. A 4" or 5" woofer in a sealed alignment will have a smaller box requirement, more bass depth, more power handling and when combined with a 1" dome tweeter, a more extended and smoother top end with better off axis response. Check out the Audax Mini on my web page. It's a way better choice than a 1.5 way TB 871 system.

So, IMHO the best options when output level is a concern are to use a single TB with dual/stereo subs and cross over active and high, 200 hz or higher. I've tried this with active 4th order high and low pass such as that provided in most HT receivers when the speakers are set to small. You'd be surprised how loud it gets. You've really got to have two subs though, one on each side near the satellites, or the bass becomes too directional.

And of course the other option is to pick a different design that suits your needs better.

[Zaph]

Originally posted by joensd
There was a recent project as HT-satellites in K+T-magazine (germany) and they reported their good sound but they also wrote that you can use them as PC speakers if you move on to the next HT system....

I sure wish there was an english version of that magazine. It sounds very cool. Or maybe I should learn German. For us english speaking folks, all we have is AudioExpress, which leans too much towards tubes and full range/high efficiency for my tastes. It lacks the great info that Klang & Ton has.

[joensd]

http://www.lautsprecher-shop.de/hifi/ct209.htm

That´s the one; nothing special really.
The 150uF is in series, followed by the rest of the components in parallel. Aim was to flatten out the "mountain" in the fr between 1.5k and 4.5k.

Yes, the magazine is quite interesting.
I only recently started picking them up (newbie) but have to say that they market them quite well; meaning only a few but good projects, informations and a lot of commercials.
Klang+Ton and Hobby-Hifi used to be one magazine but they split; maybe marketing too?

The next Hobby-Hifi issue will feature the Tangband W3-871S and a so far unknown woofer. Can´t wait to try that one.

I´ll combine the TB W3-871S with my Gradient W160AL8-MLTL (thanks GM!) but still have to sort out the crossover......

[rwaudio]

I'm using 871s in my HT setup right now.. but in a 0.2cuft sealed enclosure with the receiver set to "small" speakers and it sounds wonderful, it gets louder than I want to listen.. I'd say go for it. (sealed) as long as the listening room isn't tooo big.

[dvdwmth]

Thanks everyone,

All things considered I'm going to stick with John's original design. My Brother was emphatic about small and he has kids so its not like he needs to shake the walls. If there is a problem with output levels I'll just build a 2 way. Also, loud is pretty subjective and rwaudio's comments about getting sound levels higher then he needs pretty much answered my major concern.

[dvdwmth]

for anyone who might be having similar concerns as I had I thought I'd post a follow up now that these are done.

Using an lm1875 gainclone amp which is probably putting out about 25 watts max, Im having no problems getting comfortable listening levels. These definately dont shake the walls and I listen at reletively low levels, but they're loud enough to hear everything clearly and get into the music.

These things blow the radioshack 1197 drivers I've been listening to out of the water. Im really impressed how I can distinguish the timbre of different makes of pianos, and how orchestral music that wasn't even listenable on the rs drivers now has air around it and every instrument is distinct. I keep getting flashbacks to sitting in the concert hall.

One thing missing so far is the sound stage which I find rather undefined, but the drivers have only been playing for a day. It took the RS drivers about three weeks to sound good. My CD player is not great either so its likely to be detracting.

So add one more voice to the chorus of praise for these drivers.