Single-driver full-range speakers have a limited dynamic range. ( Limit this discussion to speakers that cover 40-20k Hz with a single driver. Let's not discuss front horns, etc where the main driver is basically a mid-range.) My Fostex FE167E speakers are limited to around 95dB maximum SPL and my Lowther speakers closer to 100dB. That's all you can get with reasonable distortion levels. These drivers are excursion limited, and in resonant cabinets, BR's, TL variants (like mine) and, BTW most highly convoluted back horns which act more like multiple TL's than true horns, they will start to run out of excursion around 80Hz. The sound will start to become muddy and congested. From a practical point of view, this simply means that there is a limit to how loud you can play your music.

The problem with limited dynamics will be most obvious with material such as romantic symphonies. The dynamic range between a solo oboe and a full blown fff tutti is something like 30dB. If you are limited to 95dB, then that oboe needs to be no more than 65dB. Now 65dB is soft.Depending on your ambient noise level, air conditioning, etc., 65dB could be in the noise floor. Of course, 95dB is really loud, ear damaging if sustained for any length of time. IMO electronic rock has more sustained high dB material and therefore overloads the speakers. Rockers are also more inclined to crank it up. Of course, I'm not a rocker, so humor me. In any case observe the above warning.

Amplifier headroom is also important here. If you are running a flea power amp an trying to get sustained 95dB out of a 92db speaker, you will be clipping the amp consistently. Without starting a flame war as to why anyone would prefer a flea-powered amp, if you want a clean 1 watt average output, you need 100 watts of headroom. Maybe I exaggerate somewhat, but you get the picture.

IMO -- YMMV.

Bob

Are there any speakers available that are 6 or 8 inch two ways, tuned to 40-50 Hz, that do a better job with dynamics then a similar sized full range design? Is the problem inherent in the size of the driver or is it particular to full range drivers with low Xmax? I am not sure it is fair to compare a two or three way design with a bigger woofer diameter with a 6 or 8 inch full range driver. I really don't know the answer to this question, I don't get out very much to listen to other commercial speakers or to other DIY projects.

Martin

Overall, Bob, you are right, a single driver non-horn, non-sub solution is great for simple music played at low volumes, but not really that good for high volume/complex music.

-akhilesh

Is it the full range driver itself that cannot do the large scale music or is it the low watt amp running out of juice?

Martin

Personally, I like a wide midrange band to cover the whole vocal range, better if covering the whole piano range. In practice, I tend to choose a driver that covers as much of that as possible, but all my systems are multi-way, so they have to crossover somewhere. Single driver systems don't have the crossover, but that means they have to choose between bass excursion and high frequency extension. The cone has to move enough to make some bass, be rigid enough to limit breakup mode peaks in the midrange, but flexible enough to have some controlled modes for top end extension.

I do full range single driver speakers because they fill a niche. A reasonable sized speaker covers most of the musical range with an efficiency that allows low powered amps. It's a bonus that given the right kinds of music, they sound incredible. It's serendipitous that those who like low powered amps generally like the kind of music that works well on the speakers.

I'm not pathologically apposed to multi-way speakers. Right now, I have the FB-16 BR's and an SP-10 sub hooked up to my HT receiver. The cross over happens digitally at around 100 Hz. This takes probably 1/2 the power off of the FE167E's and puts it on the Peerless 850148. IM is noticeably reduced. Dynamic range is noticeably increased. However, in my book, this is a 2-way speaker system. It won't work for the SET crowd because the cross over has to be done either digitally, which kind of takes the shine off of vinyl, or has to be done actively at the pre-amp level which normally means some OP amps.

Another point, and I think Wayne really knows this, is that full-range drivers work BECAUSE of cone break-up. With a full range driver, cone break-up is controlled to allow the driver to get high enough to mechanically cross to the whizzer cone or dust cap.

Bob

The horn is more balanced, than the TL, and the bass sounds pretty much in line with the highs. The mids are quite forward.

The horn seems to go as low as the TL, or at least, low enough for me.

With loud, heavy metal music-I chose this because I find most FR speakers can’t handle it at all-the horn could play very loud without losing composure. The TL was pretty mudded up at even moderate volumes.

The horn is noticeably more efficient than the TL. It plays really, really loud with minimal power.

The horn controls the low frequency excursion noticeably. Resting my hand lightly on the edge of the main cone while playing, I noted much less movement associated with the lows. Really cool.

On acoustic music horn has a mid range detail that simply outclasses the TL. The TL sounds muddy in comparison. I would have never described the 206 as muddy before, but the difference was quite obvious.