Ricci

Back to driver design. This is one of my favorite topics. I agree with Kyle in a lot of aspects. Pro woofers have the engineering, the quality control, good inductance management and efficiency , but still lack a bit in the xmax department. 15mm is plenty when the cut-off is 30Hz, but it does limit the low frequency output capability with deeper tunings. On the other end of that more Xmax costs money and increases weight. Diminishing returns kick in quick. Application matters too. A 40mm Xmax driver is probably not the best choice if the application is a 35Hz tuned bass bin for pro-audio use and the amplification will be about 1000w per driver. If the design work is right multiple smaller drivers can often work as well if not better than a single big driver. Multiple smaller coils to share the heat for one and they may have a larger selection of standard /more cost effective components to choose from. It's also easier to make a higher damped more efficient driver with less cone area and more modest components. It's way cheaper & easier to make a 10" driver with good inductance and a 0.250 Qts than it is to make a 21". On the other hand small drivers can run into real limitations for excursion and voice coil size. 10" and sometimes even 12" drivers simply don't have the room available for equivalent voice coils and suspension components, or even the motor diameter that larger sizes can use. I've thought about designing some subs and having some drivers built. I can't find any 10 or 12" drivers that are like what I'd want to see on the market for example. As far as future materials I'm wondering how long before we start seeing graphene incorporated into speaker components. I'd expect to see it in domes and cones soon if it isn't already out there.

Dgage, It probably doesn't make you feel any better but it is not just you. There are a number of companies I've declined sending me products. It's a lack of time / will on my part. I just can't keep up with the demand. I've got things in my garage that should've been done years ago and there are other guys like you that have been trying to get me to test their products for years. After we finally got the new website going this year I got more inquiries about testing immediately. I'm going to try and work through all of my current backlog this summer. Once I clean the slate off you'll be one of the first I contact.

I agree...I immediately disregard drivers without shorting rings and have for a very long time. They increase cost, build complexity and weight a bit, but greatly flatten the voltage response on both ends and lower distortion. I just assumed because the older 9500 series was so good in this regard that the new 95 series that replaced it would have similar treatment. The aluminum heat-sink on top of the motor seemed to point towards it too. The comparison of the new driver vs the older driver design at half the price will be quite the comparison.

Crest 8002. It's an old amp I leave on the bench in the garage for testing drivers.

Apparently I never started a discussion thread for the old driver test. Anyway this is a brand new 2018 built driver that will be tested in a larger sealed cab than last time. Street price on these is about $380 now. Really well controlled inductance. Tons of clearance for big excursion, legit 25mm xmax and the motor force is not nearly as low as the spec sheet suggests. The bad news is it has literally the tightest suspension I've encountered yet. Fs is up above 50Hz. It should be down near 25-30Hz on a driver like this. I have to wonder if the reason this driver came back after being discontinued is if a large OEM order came in. These used to be available in single 4 ohm or dual 4 but now only dual 4 is available. Perhaps this OEM might've asked for a slight tweak to the suspension components? Perhaps a much stiffer spider pack that would make the driver match their design using it a little bit better? One OEM that I know used these in a cab that might improve a bit with a stiffer suspension and a little more motor force to offset. Maybe MTX gets a price break on a certain quantity that is beyond what the OEM wanted so the excess driver have ended up on the market? I know none of this for sure. I'm speculating wildly here, but it sure is a fun conspiracy theory. https://data-bass.com/#/drivers/5cdee9849f167200047af2d7

This is MTX's update to the older 9500 series. I haven't ground plane tested this driver yet so I'm not going to make a definitive call on it yet. With that said I knew based on the specs it was low efficiency and I knew it was very expensive for a ferrite 15", but I was hoping it would retain the well controlled inductance behavior of the older 9515-44 and have an extra 6mm xmax, better thermal handling and lower compression, a little more cone area, even better distortion behavior and do all that on top of looking much better cosmetically. It could have been a very high performance bass pump type driver. I was hoping. Unfortunately they forgot to put some aluminum in the motor...Modeling based on the complex inductance specs pulled from this indicate it's going to have a mountain shaped response hump. I'd expect a lot of even order distortion from it at high power too. I guess we will see how it does.

I'll add some comments after I get done working on adding another driver to the site.

18 Sounds Xmax is based on coil overhang + 1/4 gap height. Same 14mm rating as their lower end drivers. It seems they only made the impedance lower and got more motor force out of it but otherwise it's no different from the MUCH less expensive 9601 drivers. So far they seem to lose composure quicker when compared with some of the other drivers too. Definitely not directly on the level with the B&C Ipal units, which are beefier upgraded drivers from the lower range B&C drivers.

Thanks for linking to the JBL. New driver name is 2288H. I was unable to find much on it yet. My gut tells me it may have similar excursion as the 2269H but slightly improved power handling and higher efficiency. Looks like it is only used in the VTX B18 at this point. I really dig the port flaring on that cabinet. It wouldn't be too hard to do something similar on a 3D printer. I'm assuming they are using a quarter section of very large pipe for the ports. Congrats on the 5000's I still plan to get ahold of one at some point.

Interesting. Got a model # or a link to the sub with the new JBL driver? I have not heard about this. Did you finally get those 5000's? We still have nothing over here.

Discussion of JBL's most powerful differential drive woofer should go here. This is an oldie but a goody. It's an expensive bugger like most of the woofers I test these days but it is still a cut above most of the 18" units on the market. I always wanted to test one of these just to see how good it is. I don't expect many people to go out and buy these for a project at those prices but it is still a common driver to see in the industry in a lot of JBL's top Pro subs. I figure giving it a run through here should help give insight into the capabilities of the various JBL subs using the 2269H. It doesn't have the crazy efficiency and motor force of the drivers coming out in the last 5 years, but it does seem to offer quite a bit of power handling and raw displacement capability. It's too bad you never see these on the second hand market for a few hundred dollars like you can pick up other legacy JBL units for. It might be an option then. The retail price is a killer. It really doesn't seem like these would be that expensive to produce either with JBL's economy of scale and having been around for so long. https://data-bass.com/#/drivers/5cd9d5e8bd4b990004557d17

Care to elaborate? I've got some myself but I'm going to let the GP testing do the talking.

I don't think it is that popular. It's not necessarily PS only. Anybody can buy the driver and it operates conventionally provided you have an amp that can drive the low impedance. Functionally this one is a 2 ohm driver which isn't so bad. I agree that it makes sense for the extra mass to be in the coil.

Not yet...There are a few outfits with 12+ Othorns though. 6 Skhorns should be able to produce the levels and frequencies you are talking about at 50m outside. 8 for a bit of extra headroom. 16 sure would be more fun though.

An NX6000DSP should be capable on a pair of 4ohm Othorn subs. 1 per channel. There are better amps out there for sure but the costs go up rapidly. Testing shows about 1800-2000w into 4ohms.

Notes and measured specs for this driver are published now. It came in a little bit different from the factory specs but some break in should do it some good. Normalized motor force of 448...

NX6000 should be a good match for a pair of cabs really.

What will you be powering them with?

Thanks for the info Gentlemaniac...Mobile or desktop and what browser are you using?

Looks good to me LSC. Better to use too much glue than not enough. You may be the first to have one running

Parameters, notes and pics of this woofer have been posted. Looks like another good 21" pro unit so far. This is one of the smoothest modeling 21's in bandpass and horn enclosures and it directly competes against the B&C units so it will be interesting to see how it compares. Suspension was extra crazy stiff on the pair of woofers I have. Even after some break in the Fs is almost 10Hz higher than factory spec. Guess I'll have to rerun it after beating on it for a years or so.

Awesome. Glad you like the sound. That delay setting trick works well to get pretty close fast. What city are you in?

It goes back to everything being a compromise. Mms is similar between the 2 which is what matters ultimately and the coil size is nearly the same as well. Copper wire of course weighs more for the same volume of material. The min impedance is 5x higher on this driver so some different choices in the wire gauge and number of turns are required to result in the higher impedance. The inductance on this driver looks good too even with the big coil. This driver doesn't have quite the same normalized motor force but its still over 300. The 2ohm version of the Ipal has a lower motor force too probably due to changes in the coil material and winding length needed.

You may have heard...You may not. Eminence is upping their game and coming out with pro woofers that compete directly with the competition. I was able to get some early samples of their 21. So far what I've seen from this woofer is very encouraging. Specs, notes and impedance curve from one of the sample units are posted. Much more info will be coming. https://data-bass.com/#/drivers/5cc9adeb9b899d0004e43084