I did some *very quick* checks and the impedance plot on the Fonken page seems to match up with the T/S parameters you measured, not the Fostex numbers. With the Fostex numbers your impedance peaks would be ~35ohm. You are showing ~20 and 45 which would jive more with the higher Q you measured.
I was very skeptical at first, but I have convinced myself that trusting your own measurements is the way to go, especially with a dataset as large as yours.
I was very skeptical at first, but I have convinced myself that trusting your own measurements is the way to go, especially with a dataset as large as yours.
Fostex TS specs.
This discussion has been very interesting. I certainly see these two drivers (126/127) in a different light. Still very good and useful drivers, but I am now thinking along rather different lines with respect to enclosure design.
Do the actual TS specs (i.e., as commonly measured) for the Fostex FE166/167 and FE206/207 differ the published TS specs in a way similar to the FE126/127?
Regards,
Bob
This discussion has been very interesting. I certainly see these two drivers (126/127) in a different light. Still very good and useful drivers, but I am now thinking along rather different lines with respect to enclosure design.
Do the actual TS specs (i.e., as commonly measured) for the Fostex FE166/167 and FE206/207 differ the published TS specs in a way similar to the FE126/127?
Regards,
Bob
No. If you try to tune them low, you're going to run out of excursion PDQ at anything more than very soft levels. They'll be OK for, say, a pair of nearfield BR monitors, providing you tune to ~90Hz or so, & don't listen too loud, but you're asking for it if you try taking things lower / louder.
reikso2h said:
Well, I've built two sets of BIBs for them. The first set uses the 43 sq inch mouth area, and is nice but lacking in bass. The second set has a 60 sq inch mouth area, but I disregarded the 1.414 width/depth ratio, so they are 12 inches by 5 inches. The bass is there but they sound "off". I've played with the stuffing a bit but I just don't like them as much as my originals.
Can't decide whether it's the narrow baffle or if it's my disregard for the ideal ratio (what would the effects of a skinny, deep BIB be on the frequency response?)
Now, if you plug in the average measured numbers posted above, you get a super-short BIB of only 36 inches or so. Would be interesting to see what that does, but my supplies of plywood are getting depleted, so I think I'll fool around with turning my second set into inverted Bibs.
They do work, and do provide usable bass, so I would say in that sense they are appropriate. I don't have any actual BLH cabinets to compare them to.
reikso2h said:
Take a look at this page.
http://www.troelsgravesen.dk/FE126E.htm
It is very well documented with several measurements.
planet10 said:
Hi Dave,
Just did a sim for the Fonken. Using your measured parameters I get very close to your measured impedance. The difference is just a few ohms, likely the influence of the damping material. Using the Fostex numbers does not produce anything close to your measured impedance. If there is an interest, and with your permission I could post the result in a separate thread since this one is about the FE126E.
Cheers,
Gio
gmilitano said:
Sure. Do keep in mind that the high ratio ports are known to push down the 1st peak & increase the 2nd peak -- that is why i need to generate sims & measures based on the same set of drivers. My 1st round of comp plots are inconclusive.
The measured FR thou -- once one takes consideration of the FE127s naked FR & baffle-step, seems to align more closely with the factory number sim... no real sign of the big hump the sim gives with the measured numbers -- but that too could be the high ratio ports in action.
dave
126 in a BR?
Suitability must first be based on the performance you require. Contrast the spl and bandwidth requirements for a case with music having a lot of deep bass at spls approaching live, in a large living room with a lot of stuffed furniture, thick carpets and drapes, versus a case with acoustic jazz reproduced at 'conversational' levels, in a cinder block dorm room with a single bed, desk, wall posters and drapes at one end.
You need to give folks here that type of information. It may be that the 126 in any existing enclosure will not meet your needs.
If your needs are similar to the second case (small lightly damped room, modest spl needs, moderate bandwidth, etc.) the 126 in a small BR may be just what you are looking for.
I have tried the FE103 (alnico version) and the RS 1197 in small BRs. In a small living room they are truly impressive, doing a fine job of conveying the musical flow and impact in acoustic jazz at moderate spls (loud enough to make conversation uncomfortable). I currently listen to them near field, at my electronics work bench where they are stunning with only a few watts input. Cone motion in both cases is nearly imperceptable - the BR loading is very effective.
There is something about the musical presentation of these small (3-5 inch) drivers that is bettered by very few speakers regardless of cost. This remarkable performance is what motivates people to push for more (i.e., full size) deep bass. Hence, the BVR's and BIB's. Within limits, 'full size' bass, can be had, but you will need to go with 'full size' enclosures.
The bottom line: if BR performance will meet your listening requirements, then the 126 will work fine in a BR. SIMs using the TS parameters measured by Planet 10 (see earlier post in this thread) indicate good response to 60 Hz (with a few db of room lift) with an EBS alignment in a approximately 0.3 cf box. I suspect that a TQWT or MLTL would provide even better performance, at the cost of greater complexity (still pretty simple though) and different placement flexibility. Using a subwoofer for deep and mid-bass duty is also a popular option.
Honestly, most people find the spl and bass capability of the 3-5 inch drivers too limited. Do not be surprised if this is the case for you. There are many other fine drivers from which to choose. Some quite inexpensive (Pioneer BUF20).
Not sure what to do? Tell folks here about your listening habits. What you like to listen to, and a little about your listening room: approx. dimensions, furnishings and potential speaker placement limitations. Also, tell us a little about your current system (power, sand or tubes, digital, vinyl, etc) and what you are seeking to improve (deep bass, dynamics, midrange detail, imaging, musical flow, etc).
Hope you find what you are looking for...
Regards,
Bob
reikso2h said:
Suitability must first be based on the performance you require. Contrast the spl and bandwidth requirements for a case with music having a lot of deep bass at spls approaching live, in a large living room with a lot of stuffed furniture, thick carpets and drapes, versus a case with acoustic jazz reproduced at 'conversational' levels, in a cinder block dorm room with a single bed, desk, wall posters and drapes at one end.
You need to give folks here that type of information. It may be that the 126 in any existing enclosure will not meet your needs.
If your needs are similar to the second case (small lightly damped room, modest spl needs, moderate bandwidth, etc.) the 126 in a small BR may be just what you are looking for.
I have tried the FE103 (alnico version) and the RS 1197 in small BRs. In a small living room they are truly impressive, doing a fine job of conveying the musical flow and impact in acoustic jazz at moderate spls (loud enough to make conversation uncomfortable). I currently listen to them near field, at my electronics work bench where they are stunning with only a few watts input. Cone motion in both cases is nearly imperceptable - the BR loading is very effective.
There is something about the musical presentation of these small (3-5 inch) drivers that is bettered by very few speakers regardless of cost. This remarkable performance is what motivates people to push for more (i.e., full size) deep bass. Hence, the BVR's and BIB's. Within limits, 'full size' bass, can be had, but you will need to go with 'full size' enclosures.
The bottom line: if BR performance will meet your listening requirements, then the 126 will work fine in a BR. SIMs using the TS parameters measured by Planet 10 (see earlier post in this thread) indicate good response to 60 Hz (with a few db of room lift) with an EBS alignment in a approximately 0.3 cf box. I suspect that a TQWT or MLTL would provide even better performance, at the cost of greater complexity (still pretty simple though) and different placement flexibility. Using a subwoofer for deep and mid-bass duty is also a popular option.
Honestly, most people find the spl and bass capability of the 3-5 inch drivers too limited. Do not be surprised if this is the case for you. There are many other fine drivers from which to choose. Some quite inexpensive (Pioneer BUF20).
Not sure what to do? Tell folks here about your listening habits. What you like to listen to, and a little about your listening room: approx. dimensions, furnishings and potential speaker placement limitations. Also, tell us a little about your current system (power, sand or tubes, digital, vinyl, etc) and what you are seeking to improve (deep bass, dynamics, midrange detail, imaging, musical flow, etc).
Hope you find what you are looking for...
Regards,
Bob
Re: 126 in a BR?
As I've said before, I'd be careful over this: the 126 does not have sufficient excursion to work particularly well in an EBS aligned BR, or a TQWT or MLTL. No way of getting around it, just a fact of life. It'll do OK in a BR providing you treat it gently & don't try going too low. About 80Hz would be the limit I'd set.
Adding a sub is usually a good idea. Preferably two.
AstroSonic said:
As I've said before, I'd be careful over this: the 126 does not have sufficient excursion to work particularly well in an EBS aligned BR, or a TQWT or MLTL. No way of getting around it, just a fact of life. It'll do OK in a BR providing you treat it gently & don't try going too low. About 80Hz would be the limit I'd set.
Adding a sub is usually a good idea. Preferably two.
Re: Re: 126 in a BR?
Scott,
I would agree that the 126 has relatively limited excursion. That along with it's small cone area, limit it's spl capability at low frequencies. However, it will work just fine up to it's excursion limited spl. If that spl limit is sufficiently loud for the intended purpose, all is well. They are really too limited for many people and I warned of this:
Also, as I mentioned above
I also mentioned that I had tried the alnico version of the FE103 and the RS 1197 in a small BR with surprisingly good results.
These (the 103's) are smaller, somewhat less capable drivers in comparison with the 126. The xmax spec for the current 103 is the same as that specified for the 126. Even so, they performed quite well within limits that met my needs. I've no doubt that they perform even better in the appropriate BVRs and in the Austin A126.
Regards,
Bob
Scottmoose said:
Scott,
I would agree that the 126 has relatively limited excursion. That along with it's small cone area, limit it's spl capability at low frequencies. However, it will work just fine up to it's excursion limited spl. If that spl limit is sufficiently loud for the intended purpose, all is well. They are really too limited for many people and I warned of this:
Also, as I mentioned above
I also mentioned that I had tried the alnico version of the FE103 and the RS 1197 in a small BR with surprisingly good results.
These (the 103's) are smaller, somewhat less capable drivers in comparison with the 126. The xmax spec for the current 103 is the same as that specified for the 126. Even so, they performed quite well within limits that met my needs. I've no doubt that they perform even better in the appropriate BVRs and in the Austin A126.
Regards,
Bob
clumsy edit
The edit button was not present so I've just posted the edit here.
The last sentence in my last post (#34) is a fragment from a deleted paragraph that more or less said that the 126's in the appropriate BVRs or in the Austin A126, would no doubt perform significantly better than in a BR".
Presently enjoying 'Tubular Bells' through a pair of BR's with EV MC8a's.
Bob
The edit button was not present so I've just posted the edit here.
The last sentence in my last post (#34) is a fragment from a deleted paragraph that more or less said that the 126's in the appropriate BVRs or in the Austin A126, would no doubt perform significantly better than in a BR".
Presently enjoying 'Tubular Bells' through a pair of BR's with EV MC8a's.
Bob
The xmax of the FE126E (0.35 mm peak advertised) is so limited I'm not sure what cab it will work well in. When I simulate it in various BLH's using Martin King's MathCad worksheets the woofer RMS displacement is always above 1.0 mm at 1w for all freqs below 50 Hz or so. Even in a small sealed box it will hit the xmax with less than 1w at freqs under 70Hz.
And yet... I know that Ed Schilling (Horn Shoppe) has measured high SPLs with his 126-based Horn ... whats going on?!
And yet... I know that Ed Schilling (Horn Shoppe) has measured high SPLs with his 126-based Horn ... whats going on?!
xmax
Holdent,
The xmax specs for the Fostex fullrangers are unusually small, among the lowest published by a manufacturer. Yet the drivers seem to perform well beyond what one would expect. My impression, after a lot of reading of key threads on this forum, is that the Fostex xmax specs are thought to be rather conservative. While the concept behind xmax is pretty straight forward, the devil is in the details. The amount of nonlinearity used to bound the xmax is not specified by Fostex (or by anyone else to my knowledge). As a result, it is difficult to compare drivers from different manufacturers. In the case of the Fostex drivers, the xmax is so small as to make them only minimally useful as a predictor of actual performance. It pays to use them in enclosures offering good loading in the bass range in order to minimize excursion. Check the Frugalhorn website to see enclosures designed along these lines for the Fostex fullrange drivers.
Regards,
Bob
Holdent,
The xmax specs for the Fostex fullrangers are unusually small, among the lowest published by a manufacturer. Yet the drivers seem to perform well beyond what one would expect. My impression, after a lot of reading of key threads on this forum, is that the Fostex xmax specs are thought to be rather conservative. While the concept behind xmax is pretty straight forward, the devil is in the details. The amount of nonlinearity used to bound the xmax is not specified by Fostex (or by anyone else to my knowledge). As a result, it is difficult to compare drivers from different manufacturers. In the case of the Fostex drivers, the xmax is so small as to make them only minimally useful as a predictor of actual performance. It pays to use them in enclosures offering good loading in the bass range in order to minimize excursion. Check the Frugalhorn website to see enclosures designed along these lines for the Fostex fullrange drivers.
Regards,
Bob
Fostex does not publish the specs for gap and coil length. I have never taken one apart, but I suspect that their Xmax spec is the gap length. Xsus is several times that. As the coil leaves the gap, distortion rises. As said above, no one knows what the distortion percents are, but as the power level increases, the coil cannot move enough to keep up, as it is leaving the gap and loosing magnetic force. This leads to dynamic compression which single driver speakers are famous for. You can burn up a Fostex with too much power, but you can never bottom one out.
Bob
Bob
FWIW, Ed Schilling has had a 126 apart -copule of nice pictures too: http://www.audiocircle.com/circles/index.php?topic=44197.msg405553#msg405553
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