Fostex FE103EN transmission line

[kctess5]

i presume by a baffle step compensation filtersyou meansound damping material

Nahh its an eletrical filter that attenuates frequencies above a certain point by 3db. When the size of the baffle is small compared to a quarter wavelength (if im not mistaken) of the reproduced frequency. At that point the sound goes from radiating into hhalf space (forward) into full space (all around) and therefore sounds quieter. To combat that you put the filter above the baffle step (that wavelenght) make the response flatter over the whole range.

Basically, the effect is boosted bass. I dont like to do this because it can cause over excursion issues, I generally try to wall or corner load the speakers to make it unnecessary or when needed add a bit of eq from my computer. It's easier and more flexible, but not everyone uses a source with adjustable eq...

[krakatoa]

This is an article about the baffle width - frequency response issue: http://www.quarter-wave.com/General/BSC_Sizing.pdf However if you want more bass (in strength) you can start by moving the enclosure closer to the walls or corners, and try different positions around the room (not just one wall, or the same 2 corners). Try to find out the position with the strongest response and see if you like it; the only thing that will make it stronger would be to put it under a desk or in some king of space that reminds an open enclosure (but then you won't be able to use it for listening, but that's the way to see what is the maximum).
The next thing is to use a different driver that has a higher Qts, a more excursion (xmax) or lower fs - these are the reasons for which you don't have much bass. As I said before MarkAudio CHR70 looks much better for this kind of enclosure (type and deep bass extension). You trade off sensitivity (4-5db). As I can see you don't know much about the theory - Loudness and Speaker Sensitivity - diyAudio - just in case you don't know what I was taking about. And another thing, aluminium cones (CHR70) don't sound in the same way as paper cones(Fe103En).

What I'm trying to say is that you do not necessarily need a larger driver, even though a larger driver will tend to have more bass, it depends again of the enclosure and driver specs. The main problem is that you may need to build a larger (by comparison) enclosure. If you have a small room stick with small drivers and choose wisely. And since we are talking about 4 inch drivers that do bass, planet10 said about CSS EL70, somewhere around the forum, that he has never heard of anything like that in the 4" class when it comes to low end. The El70 is almost identical to CHR70.

[GM]

Originally Posted by krakatoa

If you have a small room stick with small drivers and choose wisely. ..............he has never heard of anything like that [EL70] in the 4" class when it comes to low end.

Hmm, what matters is the listening distance and width of the listening position [LP] WRT room width since we ideally don't want any first reflections in front of the LP. IOW it's the speaker's directivity above ~800 Hz that matters, not how large the room is per se, so it's not uncommon to need a large driver [or horn] in a small room to get sufficient directivity at the LP.

Agreed, I was rather surprised at its ability to play Pink Floyd's DSOTM without EQing down the LF and Brian Bromberg's 'Wood' at SPLs normally too high for the apartment app they were used in. The downside to this kind of performance though is that there's no audible distortion to warn one about impending mechanical contact like one gets with a typical rising rate suspension, though at least with the pair I have they withstood several such episodes when I was experimenting with different tunings without any apparent damage.

GM

[Jameslc]

Originally Posted by krakatoa

This is an article about the baffle width - frequency response issue: http://www.quarter-wave.com/General/BSC_Sizing.pdf However if you want more bass (in strength) you can start by moving the enclosure closer to the walls or corners, and try different positions around the room (not just one wall, or the same 2 corners). Try to find out the position with the strongest response and see if you like it; the only thing that will make it stronger would be to put it under a desk or in some king of space that reminds an open enclosure (but then you won't be able to use it for listening, but that's the way to see what is the maximum).
The next thing is to use a different driver that has a higher Qts, a more excursion (xmax) or lower fs - these are the reasons for which you don't have much bass. As I said before MarkAudio CHR70 looks much better for this kind of enclosure (type and deep bass extension). You trade off sensitivity (4-5db). As I can see you don't know much about the theory - Loudness and Speaker Sensitivity - diyAudio - just in case you don't know what I was taking about. And another thing, aluminium cones (CHR70) don't sound in the same way as paper cones(Fe103En).

What I'm trying to say is that you do not necessarily need a larger driver, even though a larger driver will tend to have more bass, it depends again of the enclosure and driver specs. The main problem is that you may need to build a larger (by comparison) enclosure. If you have a small room stick with small drivers and choose wisely. And since we are talking about 4 inch drivers that do bass, planet10 said about CSS EL70, somewhere around the forum, that he has never heard of anything like that in the 4" class when it comes to low end. The El70 is almost identical to CHR70.

so would it be worth getting a CSS EL70 but from what i can see the only benifit is a flatter response in the bass instead of the dip that the fostex do ? (thanks for posting that link too i'm not really right into speaker design but everyone got to start off somewhere )

[krakatoa]

No! you get 5-6 db extra in the bass! look at the graphs at (my post) no 52, the Fostex has a loss of 2-3 db compared to nominal SPL (at which almost all the sound from the rest of the audio spectrum are) while the MarkAudio model has a gain of a few db, and it's flat down to tuning frequency. As I said before the CHR-70 will not be as loud as the Fostex (85.4<89db) but comparably it will have much more bass output.

[Jameslc]

ok well that will be another transmission line project but thanks to all who help me achieve the same sort of sound quality as the video

[GM]

Originally Posted by krakatoa

No! you get 5-6 db extra in the bass!

Yeah, to get a similar tonal balance with the Fostex will require using dual drivers and rolling one off at the baffle step. Even the couple of [others] much larger FE167E MLTLs I've auditioned didn't do DSOTM any better overall at modest average SPLs than at least the early EL70s I have. The 167's forte was the much 'fuller' mids a larger driver typically has.

GM

[krakatoa]

Originally Posted by GM

Yeah, to get a similar tonal balance with the Fostex will require using dual drivers and rolling one off at the baffle step.
GM

You've used the expression "tonal balance" as if an extra few db (see graph at post no. 52, MA CHR-70) in the 50-100 hz region is what makes the balance right, is that true? you need an extra few db in relation to the nominal SPL to get the bass right?

[GM]

Well, we want to have a ~flat in-room response [tonally balanced] down to as low as practical at low distortion if that's what you mean.

GM

[krakatoa]

My question was more like "is there a common practice to pump a few extra db bellow 100hz to please the ear rather than the measurement equipment"? Obviously the flat response over the whole audio range would be the ideal but perhaps practice had something different to say.
Is there something wrong (bass is too weak) if you see 2-3db missing like in the Fostex simulation - can you fix it by placing the terminus near the floor?