I just wanted to pass on initial impressions from my new Acoustic Elegance TD18H+ as it has made quite a positive impression. I admit to being a little unsure of my need to buy one given I already had a Peavey Black Widow 18 driver in action. However, once I installed the TD18H+ it was easy to work out why it was more than twice the price of the BW! Great bass makes for great music!
The bass is just so clear! I didn't think it would make such a difference as I am currently running them from 70Hz down. However, I am getting great response and serious punch from the AE driver, more so than before. Just put on a rock album and the bass drum kick is phenomenal. They are paired up with AE TD15S drivers for mid bass and the Unity Horn for the mids and up.
I obviously need to do some measurements to see if I can determine what the difference is. I am aware AVS is about measurements and not subjective opinions. I think that measure distortion' function on REW looks like something to explore. Any advice on what to measure (and how) would be greatly appreciated.
Next steps are to try the TD18H+ in a 90L sealed cabinet (like Findbuddha) and also try crossing the TD18H+ a little higher. My next project is building some cabinets for dual TD15S drivers so I can compare them directly with the single TD18H+.
Here are the T/S parameters for comparison:
Acoustic Elegance TD18H+
Fs: 29Hz
Qms:5.9
Vas: 390L
Cms: .185mm/N
Mms: 165g
Rms: 5kg/s
Xmax: 14mm
Sd: 1220scm
Qes: .23
Re: 5.6ohm
Le: .41mH
Z: 8ohm
Bl: 27Tm
Pe(cont): 1000W
Qts: .22
1W SPL: 98.2dB
Peavey Black Widow 1888HP BWX SPLi= 95.24 dB SPLo= 96.39 dB RMS=650W
Have they changed the phase plug? It looks more pointy.
I did a sim of this driver they other day and it seems it's made for a small box (relatively) with extension intended for music, and due to the low Qts it doesn't like to go low. It's a driver I've been very curious to hear.
Findbuddha did a test and gave me some positive feedback about crossing his TD18H at 300Hz. However, the thought of 6 AE drivers handling bass is not so bad
Quote:
Originally Posted by paulspencer /forum/post/20089967
Nice!!!
Have they changed the phase plug? It looks more pointy.
I did a sim of this driver they other day and it seems it's made for a small box (relatively) with extension intended for music, and due to the low Qts it doesn't like to go low. It's a driver I've been very curious to hear.
They have definitely tapered the phase plug, thank goodness!!!
In a relatively small sealed box, 90L, Qtc is 0.533 but it will need a bunch of EQ to get it flat to 20 Hz as it starts falling off around 100Hz. I think with the 14mm Xmax it's workable
the look with the pointed phase plug is much better. props mr. j.
the first thing that is going to make them more clean than something like the black widow is the copper sleeved pole piece. that will reduce and linearize inductance, which is a primary source of distortion.
this driver also has a very low qe, which means it has a combination of strong motor, light cone and compliant (soft) suspension. that all adds up to very good quality sound.
don't quote me on this last point, but with most pro audio type 18's, the kind you might get from 18sounds or jbl for example, the damage point is much further past the xmax point in order to allow for a ton of overshoot. the td18's xdamage point is not much past its xmax point, so be careful to control/limit your excursion.
this driver will play bass, mid-bass, and midrange...so no need for mid bass modules. unless there is some resonance, and i doubt there is (john j is pretty good about the first ones, which are spider and surround induced) around 350hz, you could probably use this 18 as high as you want (~750hz where it, as an 18 inch driver, will start beaming isn't out of the question).
i don't know about ventilation / long term cooling, so for high power pro audio applications, somebody else will have to weigh in there. john j. has said the copper plated pole wicks heat better than some other designs, but who knows.
Quote:
Originally Posted by LTD02 /forum/post/20090288
this driver also has a very low qe, which means it has a combination of strong motor, light cone and compliant (soft) suspension. that all adds up to very good quality sound.
don't quote me on this last point, but with most pro audio type 18's, the kind you might get from 18sounds or jbl for example, the damage point is much further past the xmax point in order to allow for a ton of overshoot. the td18's xdamage point is not much past its xmax point, so be careful to control/limit your excursion.
Yes, I did make note of the low Qe in my decision. The motor is enormous compared to the Peavey.
I did a few sims to see what might happen with an LT and compared with the TD15S (pair). The results are as follows. Essentially I have fed all of the drivers 200W and the LT is to 20Hz. Even if I use 27Hz, about as low as a piano will play, I get overexcursion. Seems like I need that Maelstrom afterall!
Antripodean, glad to hear these are working well. IMO the vented box is really the way to go vs a sealed. They have high motor strength designed to be able to work very well in vented cabinets. One thing you should try is getting the Black Light Syndrome album. Track 3 is Duende and there are some quick bass notes played by Tony Levin at the beginning. Compare to any other driver. Even with an 80hz crossover you'll hear distinct notes with the TD18 while other drivers will produce more of a rumble that changes tone but the notes aren't very distinct. I've done this demo with TD18's and B&C 18TBX100's side by side in identical enclosures and the difference was amazing.
LTD02, the one way Xmax on these drivers is 14mm. The actual suspension will do 23mm one way. This was the longest travel 18" surround I could find. The spider really is good to 30mm+ so the surround is the limiting factor. In any case there is a good 60% extra travel beyond Xmax before damage.
I have someone locally using 24 of the TD18's for live sound use on an almost nightly basis. He has build three systems and replaced all his B&C 18's with the TD18's. We have had one mechanical failure where he ripped the cone off the coil. The band had a 5 string bass and keyboard with lots of low end and he had taken out the 28hz highpass and run the subs fullrange. He was also using only 4 woofers in this application where he typically would have used 8-12 but the other woofers were out for another gig. The woofers are fed 1250-2500W each from lab gruppen amps on a nightly basis. There has only been that one failure in almost 2 years of using these drivers now. The VC itself did not look to have ever been warm even. If I can find a camera I'll take a pic of it.
John, glad to see you drop in. What are your thoughts on using several (2-6 td18's) in sealed enclosures in a small room for HT use? My room is 2,000cuft. I know they have an early rolloff when sealed but in a room like mine I could see the room gain helping a lot. Then there is EQ and all that. I even think the rising response may even be beneficial for some where the upper end (50hz-120hz) is kinda... meh. My room suffers from that.
Just sounds like a cool idea to use these for all the bass if you could.
thanks for the info j.j. i had written down "in my head", 19mm, but 23mm is pretty much up there with the best of them. 14/23 is a good ratio for this application and i'm glad to hear that they can take a beating over time. durability was a question before, i suppose that question is being put to rest.
any thoughts on which measure would quantify the subjective cleanliness that you are hearing on the duende track? i've seen that you have mentioned this several times, so it is probably quite dramatic.
scott, they will work very well. the reason that you never see such a build is that it gets very expensive. for you, 8 drivers would be the ante...
remember winisd models 2 pi space. in a real room, like scott is talking about, you get pressure vessel gain. this kicks in typically around 25hz +/- and provide a theoretical 12db per octave of free boost (but in reality, because of lossy room walls, air leaks, etc., the boost is 6-9db per octave).
the frequency where it starts to kick in is ~= 565 / Sqrt(L^2 + W^2 + H ^2)
Originally Posted by Scott Simonian
Man... I'm having deja vu here of Tack's old thread. Maybe I've just read it too many times.
Just sounds like a cool idea to use these for all the bass if you could.
Yes, I read Tack's thread and was impressed how he tuned them well below Fs. I keep looking at my ports to see how I can tune lower
I too think a wall of these babies would definitely be the way to go!
Quote:
Originally Posted by LTD02
remember winisd models 2 pi space. in a real room, like scott is talking about, you get pressure vessel gain. this kicks in typically around 25hz +/- and provide a theoretical 12db per octave of free boost (but in reality, because of lossy room walls, air leaks, etc., the boost is 6-9db per octave).
the frequency where it starts to kick in is ~= 565 / Sqrt(L^2 + W^2 + H ^2)
numbers in feet.
Thanks for the formula. My mic is on loan at the moment so once I get it back I will take some meaurements as well. I am keen to at least try the sealed option. As a thought, I can fit two sealed TD18H+ in the room for every one ported (stacked). That has to be a good thing!!!
no problem. what is actually going on at that point is that the long dimension of the room is less than one half of a wavelength. as a result instead of the sound wave bouncing and reflecting around the room, the pressure in the room just goes up everywhere. the speed of sound is ~1130 feet per second. 1/2 that is 565. that is where the 565 is coming from.
I am shopping for an 18" sub for HT duties...it will go in a 7 cuft ported box.
would this be a better driver than the Fi or t he IXL? ( my two current options )
I must say from the looks of it , me like!!!
Box is already built...
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