If ya aint making waves , then ya aint rowing.
ron

I agree with your path 1 assessment. To acheive deep bass (say in room flat response down to 30 Hz) from BLHs, the cabinets must be huge and extremely stiff. The practical alternates are to ignore the lack of bass or somehow augment with a powered woofer. IMO many listeners have unwittingly learned to ignore a lack of deep bass or have never heard deep, musical, dynamic bass and so they underestimate these considerations.

Regarding your path 2 discussion: One significant advantage I find in BLH, OB, TL or pipe designs is that they direct the rear wave so as to avoid reflecting back to and through the semi acoustically transparent driver cone to be heard as a time smear form of distortion. Because of this time smearing, I'd love to find more commerically available TL sub options.

IMO the dynamics of one speaker cabinet design versus another is primarily dependent on the driver efficiency. Seems that the confusion and debate of cabinet types comes in due to high efficiency drivers which often have low Qts values and therefore correlate most often with BLHs. And so BLH cabinets are praised when its the drivers that dictate the choice of cabinet designs in the first place. Note that the highly praised and approachably priced extended range Visaton B200 driver offers an alternative to BLHs with it's high Qts and high efficiency.

I'd prefer to see a sub crossover lower than 200 Hz, but am eager to audition Retsel's Lowther/OB.

The amp is the X150......the speakers are a 4"BLH. The speakers are in corners..the room is 16 X18. The SPL was at the couch. The distance from the right and left speaker to the SPL meter was 15 feet. My buddys' name is Larry....he is a musician and plays around town a couple times a week. Believe this or not. I don't care. This is in his own words.............

I'm Larry, and I just sat here 15 feet away from the system listening to Metallica playing Enter Sandman @ 106 db peaks. The average volumn during the quiet portion of the song (the speaking part) was 100 db. I could detect absolutely no audible distortion at any point. In other words, the system kicked ass! Yes..I am a musician; and I know what loud music is supposed to sound like. The bass response was just fine, and there was certainly no need for a sub woofer at that volumn. I have previously listened to the system with a sub woofer, and it probably sounded a little better at low volumn; but I never really thought it needed one.

And that's the way it is....and all he would type! I simply asked Larry to type what he heard.

Now, other than a BLH....exactly what single driver design with a single 4" driver, can make those SPL's? A TL, a BR , a sealed......well not that I have been able to see actually demonstrated. Keep in mind we are talking a 4" single driver, not an 8, not a multi driver, but a single 4" driver. It seems that a BLH just might have an efficiency edge over other designs, unless of course one of them can achieve the same outputs using a COMPARABLE size driver. The BLH is a much more efficient type of design, I have found. I will give examples of real speakers in my next post....which may not be until tomorrow. In the mean time and I have said it over and over....in the world of single driver speakers....efficiency and small cones are your friends. Excursion and low efficiency is your enemy......My opinions OK.
Ed

BTW...I did not edit or spell check Larry's writings!

I've rarely found any metal to sound good on horns or other dynamic speakers. It is mastered to sound good on typical home stereos. Metal sounds best IMO on lower efficiency but fairly large multiways, but can be OK on low efficiency single drivers, like say the cheap delco fullranges in your camaro... I've listened to enough metal as a teenager for one lifetime already, but that's a different subject.

To sum it up, I think it's more a matter of efficiency and low distortion. Heavily produced rock and metal thrive on a bit more compression and squashing of the peaks even at the playback end; while classical, jass and other well recorded music sound best with higher fidelity. I doesn't surprise me that little fostex FR's in small backhorns sound pretty good with metallica, as they are not that efficient and no doubt squash dynamic peaks.

Greg B

I hope you're not saying they don't! I'll get some SPL readings on some of what you call "dynamic music" as well. And post them....regardless of the results.
Ed

No, I'm not saying that at all, in fact that's their forte. But not all single drivers are the same for sure. It was interesting for me to try the FX200 in both the factory BR and a TQWT of my own design (with help from Martin King's software). The BR was less dynamic for sure but seemed to take the edge off rock and other 'produced' recordings, and the ~4kHz peak inherent in the driver's response was much less noticeable in casual listening. The TQWT was designed to have enough gain in the upper bass to not need BSC. Overall, the measurements were quite similar, but of course the BR did not go as low. BTW, the factory BR design is a bit high tuned and warm sounding, which seems to be intentional - to negate the need for electrical BSC.

Anyway, the TQWT was certainly the clear winner in terms of high fidelity and was remarkably lifelike. OTOH, the BR was much more forgiving, but sounded like a stereo rather than the real thing. So, here we have a situation with the same driver, where one enclosure might be more suitable for classical and other dynamic recordings, and the other better for rock, etc.

BTW, since I'm moving in a couple weeks and will no longer be in a converted warehouse, no more huge format HE system for me. I think I'm going to try my FE108E sigmas in backhorns... They're really my fave fostex so far, and I've tried quite a few. Maybe I can make my big TL sub a couch??

Rgds,
Greg B

But no matter what you do - horn, reflex or transmission line - the bandwidth required is the same. A single driver is required to cover the entire audio band. That means the intermodulation issue is the same cross to bear for each of the three designs. And while excursion is limited at certain frequencies in each of the above mentioned designs, you still need to have displacement to generate bass, and that means excursion.