I’m sorry I didn’t understand, and I apologize. I thought that Bob only meant that excursion above Fb was a bigger problem than beneath it. Well, by default excursion is minimal in the Fb point, that’s what ‘tuning’ is about, and it gets bigger both above and beneath it. And as already said, if box tuning gets deeper, excursion rises more in the upper bass region.
It is also perfectly logical that the smaller the driver is, the less acoustic volume it can obtain mechanically.
But problems arise (in most practical applications) mostly beneath it, as I believe, especially with small drivers, as is the case with this here. Attached, this tangband in 3litter tuned at 80Hz as suggested in this thread (1W input);-)
I believe that such a small speaker is a good experiance nevertheless and a fine starting point, if someone doesn't expect greater than 95dB in-room volumes. Later, it can be easily expanded;-)
It is also perfectly logical that the smaller the driver is, the less acoustic volume it can obtain mechanically.
But problems arise (in most practical applications) mostly beneath it, as I believe, especially with small drivers, as is the case with this here. Attached, this tangband in 3litter tuned at 80Hz as suggested in this thread (1W input);-)
I believe that such a small speaker is a good experiance nevertheless and a fine starting point, if someone doesn't expect greater than 95dB in-room volumes. Later, it can be easily expanded;-)
Attachments
Dear Bob, I wouldn’t think it is irrelevant, because it will run out of excursion capabilities first in the bellow 70 Hz region, where there is still enough content of fundamental frequencies in any music ;-) I believe I have supporting experience as well.
Excursion in various input Wattages will be obviously exactly analogous to what I’ve already posted (half the excursion for half the input Voltage, in all frequencies).
Furthermore, there is no need to get anxious for the exact 1mm linear excursion capabilities, I wouldn’t care about them in such a design, since in practice much more excursion can be obtained without audible real disturbance, and with still acceptable sound quality. If 92-95 dB in-room volumes are acceptable, such a configuration is perfectly acceptable for a first project, in my view, and such a speaker will suck out some 8-10 Watts in real world circumstances and real music, as I have experienced, with only minor problems from time to time.
Regards,
Thalis
Excursion in various input Wattages will be obviously exactly analogous to what I’ve already posted (half the excursion for half the input Voltage, in all frequencies).
Furthermore, there is no need to get anxious for the exact 1mm linear excursion capabilities, I wouldn’t care about them in such a design, since in practice much more excursion can be obtained without audible real disturbance, and with still acceptable sound quality. If 92-95 dB in-room volumes are acceptable, such a configuration is perfectly acceptable for a first project, in my view, and such a speaker will suck out some 8-10 Watts in real world circumstances and real music, as I have experienced, with only minor problems from time to time.
Regards,
Thalis
I did a bit of playing around with the 871 in a 3 liter BR tuned to 80 Hz. I allowed the Xmax to be 1mm. To get the entire excursion curve below 1 mm, the power level has to be set at 0.15 watt. This gives an SPL of ~80 dB/w/m. This is probably OK for computer speakers where you won't have to worry about BSC, and of course, you have two speakers which gives you 83 dB/w/m.
Now, my comment about the excursion below Fb is based on my opinion that this kind of speaker really needs to be high passed to eliminate the bottom end. Doing this, you can run up to 0.9 watt and get nearly 90 dB/w/m out of two 871's
If I were to build computer speakers around the 871, I'd go tune a 3 liter box to 100 Hz and high pass it there. That will give you a 3 dB peak to handle BSC and allow a full 1 watt of power.
Bob
Now, my comment about the excursion below Fb is based on my opinion that this kind of speaker really needs to be high passed to eliminate the bottom end. Doing this, you can run up to 0.9 watt and get nearly 90 dB/w/m out of two 871's
If I were to build computer speakers around the 871, I'd go tune a 3 liter box to 100 Hz and high pass it there. That will give you a 3 dB peak to handle BSC and allow a full 1 watt of power.
Bob
Its amazing how you keep on going about it when I have posted a thread link with a 3 litre bipolar using 2 such drivers per cabinet, that is more than OK for 26m2 and has been knownly cloned by 2 people already (one in California and one in Netherlands with comments in the thread). I just advise our friend to email the one in Netherlands so he can give him details of how deep/loud/good is it in his room with his Hiraga amp. Why you dissapoint the thread starter out of hand without experience on the matter is just beyond my comprehension.
2.83V I used In original TB3 without tweeter and notch.
The Revisited takes happilly my 20W per channel amp without audible distortion.
The Dutch builder has a Hiraga, doesnt state which one, but Hiraga never published less than 8W S.S.
The Californian man has a T-Amp (10-20W) and states that the bass is the best he got from 871s. Check his site, he has built many nice looking speakers with TB871.
So thinking of 1 or 2 W power handling only is gross error.
The Revisited takes happilly my 20W per channel amp without audible distortion.
The Dutch builder has a Hiraga, doesnt state which one, but Hiraga never published less than 8W S.S.
The Californian man has a T-Amp (10-20W) and states that the bass is the best he got from 871s. Check his site, he has built many nice looking speakers with TB871.
So thinking of 1 or 2 W power handling only is gross error.
Bob Brines said:
Can't use one driver in a 6liter BR tuned at 61hz, without a highpassfilter I could get 80hz. My cone excursion would get worse with 1mm at 0.6watt(~84dB) and 1.8mm at 2watt(~90dB). If I would put max. power of 12 watt in it I would get 4.6mm excursion(Would that destroy my driver
or just make it sound really terrible???)
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.