Originally Posted by Martycool007
Something that I am not clear on with regards to the TD18h woofers is how do they differ in terms of sound quality in a 2-way or 3-way setup compared to using something like a Seas L18, or W16, or perhaps a Scan Speak 18W? Both the Seas and the Scan Speak will easily go down to 60hz in the right enclosure, and I believe that they will go up as high as the TD18.....so what is to be gained with a pro-woofer, such as the TD18h or TD15, over the Seas or Scan Speak? Not trying to be snotty as I am genuinely curious about this.
The comparison really isn't a realistic one as you will see. As mentioned you would need a ton of the L18 to equal the output of a single TD18H+. A total of 23 of them to get the same low end displacement. If you didn't need the low end output and are just talking about upper end, the other difference is efficiency. 98db vs 87dB mean the single L18 needs over 10x the power to get to the same output as the TD18H+. A driver with 1/10 the power handling that needs 10x the power to reach the same level is not realistic. You are also comparing one driver with inductance control and one that does not have any.
A more realistic comparison if we are talking about midrange/midbass is the Seas Excel 10" or Scan Speak Revelator 10" vs a similarly sized TD10H. Both have shorting rings to bring down inductance and lower distortion. The Revelator shorting ring is much more effective due to placement, bringing down Le to .3mh while the Excel still has an Le of 1.43mH. There are other significant differences though. The motor strength of the TD10H is far more. Bl^2/Re is 64 in the TD10H compared to 16.47 in the Revelator and 17.26 in the Excel. This makes the TD10H 2-3dB more efficient so it will take less power to get loud and work in a smaller enclosure as well.
The biggest difference though is in displacement. The Excel has 7mm Xmax while the Revelator has 9mm. The TD10H however has 14mm Xmax and 20mm of suspension travel. It will take 2 of the Excel or 1.6 of the Revelators to equal the low end output of one TD10H. The TD10H has a real power handling 2-3x higher than either of those drivers as well. Then consider both of those drivers are already about $100 more.
Other drivers in the same general class as the TD10H would be the Audiotechnology Flexunits, ATC, Dynaudio, Morel Ultimate, Focal, etc which are all significantly higher, have less power handling, less Xmax, and do not have the low, linear inductance of the TD10H.
Originally Posted by zora
I don't think any knowledgeable individual would say that your drivers aren't worth the asking price, but we must be honest about the JBL and TAD drivers. JBL got out of the DIY business years ago and raised the prices of their drivers to an ultra premium level. The technology is solid, but they are overpriced (same as the TAD drivers). We DIY'ers are such a small market that missing a few sales from us doesn't register with them. You are filling a gap in the market, and I think that most of hope you can succeed long-term.
See the above part regarding all the other available DIY drivers out there. Whether it is these companies or the pro companies, there is one huge difference. I build the drivers and sell them direct. The other companies sell through standard distribution channels. Each step along the way of regional/national sales reps, wholesaling, warehousing, retail, etc is getting a portion of the overall sale which bumps up the cost to the end user. Not to mention the money spent on advertising. The raw parts cost in the TD18H+ before I spend a minute assembling one is already higher than the cost that these drivers are sold to the wholesalers. I would rather put the money into quality components and sell directly to the end user so they receive the benefit of a better product.
Originally Posted by LTD02
the next closest thing in the market to the td18h+ is probably the 18sounds 18lw2400 or the b&c 18tbx100. the 2242 price is no longer competitive.
It depends on the basis of comparison if this is realistic or not. Cost wise they are less but these drivers both have only 9mm and 9.5mm Xmax vs 14mm Xmax of the TD18. The B&C has nothing in terms of impedance compensation or inductance control and has 4x the inductance. The 18sound has over 3x the inductance of the TD18H+ . While the demodulating rings help to reduce distortion some, nothing works like the full sleeve of copper over the entire pole to force the coil to act as an aircore inductor over the full travel. While many consider this to be out of band, the 18Sound has a massive breakup from the dustcap about 1.6KHz as does the B&C. If using for pure subwoofer duty, it may not be an issue. If using the driver up to 300hz in a 3way system, that places the 5th harmonic right about that point. Higher, odd order harmonics are very audible and much related to inductance. While price wise those drivers may be less, you need multiples to equal the output capability of the TD18H+. In terms of clean output they also don't compare directly.
Originally Posted by Elill
I cant vouch for Scan Speak, but IMHO the AE drivers deliver better mid bass and midrange compared to the Seas drivers you mention. I also think AE is better than the current PHL driver I use. None of this is based of measurements as the Seas, PHL, and AE systems I have spent a good amount of time with measure relatively similar. I just found the AE drivers to deliver better mid bass detail. ....just my 2 cents
Originally Posted by Martycool007
Thanks for the replys gentlemen! So basically what it comes down to when comparing the TD18's or TD15's to the Seas L18, Scan Speak 18W, or Scan Speak Revelator, is that they will have more SPL in the lower and upper mid-bass & mid-range frequencies and give you a more "kick you in the chest" type of feeling? I can't help but wonder how the actual sound quality between the two would compare.
I am in the process of doing a speaker build that was on the Zaph Audio website, and it uses some of the Scan Speak drivers. I have also been planning on building some Seos-15's when they become available to use at my fiances' apartment. I wish that I could afford to buy some of the TD15's to use in the Seos-15 build, and also some TD18h's to use in dedicated mid-bass cabinets that will be placed under each of my LCR Sieraa-1s.
Unfortunately, I can not afrord the AE drivers, so for the Seos and midbass cabinet build I plan to use the JBL2226. Anyway, good discussion guys!
There always tends to be discussion about the "sound" of a woofer. A good woofer shouldn't really have a sound to itself. Many woofers can be considered "smooth" because the top end rolls off. Or they are considered to punch or kick hard because the inductance creates a bump that exaggerates somewhere in the 50-100hz range. They are considered to cut or be bright because they breakup around 3KHz. Characteristics like that IMO are not good. A woofer should be able to most accurately reproduce what is input to it without changing the sound at all. Those characteristics are things put into the sound by the musician when it is made. You want to be able to hear things as they intended, not add the same brightness or smoothness to everything you listen to.
The real basis for comparison would be to play a given waveform through the speakers and record it. Then compare the recorded wave to the original. The woofer that has the most linearity in terms of Bl and Le will best be able to recreate this waveform. Le(x) and Le(i) distortion will physically put the VC in the wrong position which greatly distorts the waveform. You can see in this FEA analysis with and without the aluminum shorting ring on the OD of the coil how the eddy currents affect the flux near the gap. Without the shorting ring, there is a lot of flux modulation around the gap on both sides. The shorting ring removes all of it at this position.
The main issue is that this flux modulation affects the position of the VC. The following graph shows the curve with the shorting ring and without the shorting ring in red. This is not an optimized shorting ring, but you can clearly see that the coil is in a different position with and without the coil.
If you want to accurately reproduce a signal, the coil has to be in the right place at the right time. If it isn't, it is reproducing something else. Slower continual tones like sine waves are less effected. Quick transients are much more critical in terms of VC position with respect to time. When you play both at the same time is when it gets really messy. I have done the comparison with a TD woofer with and without the copper sleeve on the pole. There is a world of difference in terms of being able to reproduce a hit on a kick drum, snare hits, slap bass, or striking keys on a keyboard.
I realize that a used 2226H may be able to be picked up cheaper. I've had many people offer to sell them to me or ask me to find homes for theirs after upgrading to TD15's. A used driver you don't necessarily know how it was used though. You don't necessarily know what parts were put in to a reconed woofer either. Just be aware of those things. There are very few TD woofers that end up on the used market. If an issue does arise that is not covered under the 3yr warranty, a factory done recone here is $75 plus parts. Typically about $125 total.
Originally Posted by chrapladm
The 18 Sounds LW2400 is a lot cheaper for me compared to the AE TD18H. I can actually get the next high end model up and still be slightly cheaper than AE. BUT I think the AE could still be used higher than any of the 18 Sound 18" drivers regardless of price. Although I am not intimate with all the 18 Sound drivers so I could be wrong. I still have to wait till beginning of next year for my 9600C's.
The 18sound LW9601 is a fairly comparable driver because it does have the 14mm Xmax. The issue is inductance is 2.1mH and the efficiency is only 94.6dB. Also look at the response curve. Inductance causes the dip centerd around 800hz, then the duscap breakup at 1.6KHz is there.
Originally Posted by LTD02
there is also the b&c 18sw115 floating around as a close price competitor.
not aware of any 18" drivers with as good of inductance control though.
Price wise that is a good comparison. Xmax is 14mm making it comparable too. As you mention though, inductance is almost 5x as high and without the linearity.
With any comparison you need to make sure you are comparing something similar. Between 18" drivers most all will model with similar response curves on the low end. The pro style 18's are designed most typically for 6-8cf front loaded vented enclosures. The TD18H+ and B&C 18TBX100 model nearly identically below 60hz. The 18sound, BMS, EV, JBL, RCF, etc all have similar response curves in that range so they can be compared on that basis. Power ratings are mostly similar as well. In terms of output, these are almost always excursion limited in their applications, not thermally limited. There are a lot of drivers in the lower Xmax range of 6mm - 9.5mm. These can be found cheaper, but if you need the lower end output aren't really a good option. There are only a handful of options with 14mm or Xmax, and none are less than the TD18H+.
Look at everything including Xmax, low and linear inductance, efficiency, and a smooth frequency response well upwards of the crossover point. You won't find another driver that has this combination.