Jump to content
jpmst3

Upcoming Testing Possibilities?

Recommended Posts

Not sure if tagging works the same here but ...

 

@Ricci

@electrodynamic

 

Inevitably the new BHS-24 will get tested. The obvious question will be how different is it from the "regular" 24" driver.

 

Should the new driver be tested in the same 15cuft enclosure or a smaller one?

  • Like 1

Share this post


Link to post
Share on other sites

Looking forward to seeing how the NS18 handles your torture tests! Problem is the flange is a bit bigger than the open tool 18" baskets, so you might have to do a new baffle.

 

I can already tell it is an extremely low distortion driver. Impedance curve alone says that. It does have quite a bit of excursion too. Still solid by modern standards. I am a bit worried about the single layer, short coil during the high power tests. I really don't want to damage it. It's such a nice looking driver.

Share this post


Link to post
Share on other sites

I have my new 18" and 21" vented cabs in which will be used for testing the occasional driver. Thanks to Nathan Funk for building those. The design details are as follows.

 

Both are void free 18mm BB ply. Both have a deep 3.5" recess from the baffle to the front of the cab so a steel grille will clear even the tallest surround, longest throw drivers. The baffles are double thickness. Bracing is simple but is a large cross brace connecting the sides, top, back and bottom of the enclosures. The vents are 3 large slot ports on each. The plan being to be able to run the cabs with any combination of vents open or with all blocked as a large sealed. These cabs are pretty large in order to work well with as wide a range of drivers as possible. Those having moderate to low motor force will matchup a bit better for the most part and those having higher motor strength will end up a bit peaky at the vent tune. Another reason to make the internal volume a bit bigger was to get as large of a vent area as practical while getting the tunings into the range wanted. the plan was one port open being a typical low HT tune of near 16Hz, 2 ports open being a more usual versatile tuning of around 23Hz and with all ports open something closer to what a pro audio or car audio cab would have at around 30Hz. I couldn't quite get the full spread of tunes I wanted but as we all know it's about the compromises. It will be interesting to see what the tunings actually come in at. I suspect a little lower than calculated.

 

 I'm not going to test every driver in these cabs. It would simply take WAY too long. The sealed cabs will still be the default test boxes as that is the simplest most effective way to compare driver for driver. These will be used with the occasional driver that does very well and will provide a comparison to the sealed data and how the vent, bigger cab and or different tunings affect its performance. Then educated guesses can be made about how these things would affect other drivers.

 

18" enclosure is 35.5"D x 30"H x 22.5"W

The vents are each about 34.5" long (Depending on the loading of the internal opening)

The cross section of each vent is 170.5mm W x 125.5mm H (213.83cm area each)

All vents open 233L Net (29Hz tune) (641.5cm of vent)

2 vents open 251L Net (22.7Hz tune) (427.66cm of vent)

1 vent open 269L Net (15.5Hz tune) (213.83cm of vent)

All vents blocked 287L Net

 

21" enclosure is 36" D x 30"H x 24.5"W

The vents are each about 34.5" long (Depending on the loading of the internal opening)

The cross section of each vent is 187.5mm W x 130mm H (243.5cm area each roughly)

All vents open 255L Net (29.6Hz tune) (730.5cm of vent)

2 vents open 274L Net (23Hz tune) (487cm of vent)

1 vent open 293L Net (16Hz tune) (243.5cm of vent)

All vents blocked 312L Net

 

 

 

post-5-0-10998200-1448384925_thumb.jpg

post-5-0-44027600-1448384929_thumb.jpg

post-5-0-78648000-1448384933_thumb.jpg

  • Like 2

Share this post


Link to post
Share on other sites

Will the ports be blocked off on the inside or outside? If they're blocked on the outside, does the area inside the port get added to the cab volume?

Share this post


Link to post
Share on other sites

Will the ports be blocked off on the inside or outside? If they're blocked on the outside, does the area inside the port get added to the cab volume?

 

Outside. Yes it gets added and was taken into account during the design.

Share this post


Link to post
Share on other sites

Will these be used for new drivers coming in, or do you have any plans to go back and measure a driver already tested in sealed?

 

I look forward to seeing these. I only have a single sub, an SI HST18 in a +/- 300L net, 16.5hz tune. It is very close to your test box. 

I get you aren't a DJ "taking requests", but would love to see some of the popular DIY 18" drivers tested in the vented enclosures.

 

RK

Share this post


Link to post
Share on other sites

Will these be used for new drivers coming in, or do you have any plans to go back and measure a driver already tested in sealed?

 

I look forward to seeing these. I only have a single sub, an SI HST18 in a +/- 300L net, 16.5hz tune. It is very close to your test box. 

I get you aren't a DJ "taking requests", but would love to see some of the popular DIY 18" drivers tested in the vented enclosures.

 

RK

 

These will probably only get used a few times. The reason is it takes the same amount of time to test one vent tune as it does to test the normal sealed cab. All 3 tunings will take many hours. I don't know if I could get 2 drivers done in a single 8-10 hr period. Also that is a severe beating on the driver. That's not one high power test and done...It's 3 or 4. Like I said I will probably only do a few drivers which are representative of very high performance or popularity. Once 2 or 3 drivers are tested in each cab it will be realistic to make educated assumptions of how other drivers will behave based on their sealed results in comparison.

 

I'd probably do something like these drivers.

BMS 18N862 to represent a very good pro woofer

LMS 5400 to rep an long throw driver with "ideal" behavior

HST18 or SP4 to rep a long throw driver with some inductance related effects.

 

This would give a good snapshot of how various "good" representatives of each driver type behave.

  • Like 2

Share this post


Link to post
Share on other sites

Yeah. Looks impressive with some pretty stout specs. Not sure if it would really "best" the 152. I think this one is even more of a bass/midbass when compared to the 152 though. Even B&C recommends a small/medium resonant enclosure tuned to 40hz.

Share this post


Link to post
Share on other sites

 

Anybody else noticed B&C's new 21DS115

 

Any place for it in the Othorn Ricci? 3db more sensitive.

 

 

 

Haven't modeled it yet. I have posted the Othorn HR inputs a few times so you could model it yourself or I'm sure someone else would help out. Looks like a good driver. 3dB more sensitive at what frequency? It has less motor force so it isn't quite as efficient. Should be pretty similar though.

Share this post


Link to post
Share on other sites

In other news...I've been out twice this week. I'll be posting the results for the Aura NS18 soon and some other things.

 

I also tried to run the 21IPAL driver through testing again. This time I crammed 2 in the tiny 5.5ft dual opposed sealed cab I previously used for the 21SW152's, so I could get a 2ohm nominal load for the amp. The K20 still current limited well before getting to the driver limits. Not surprising since the minimum impedance is dropping down near 1.5ohms and the amp is rated for 4ohm bridged. Thankfully those amps are so well protected they won't let you blow them up even when you do something stupid. Next time I'm out and going to let one channel of the SP2-12000 have a go at this cab and see if it does any better.

  • Like 1

Share this post


Link to post
Share on other sites

In other news...I've been out twice this week. I'll be posting the results for the Aura NS18 soon and some other things.

 

I also tried to run the 21IPAL driver through testing again. This time I crammed 2 in the tiny 5.5ft dual opposed sealed cab I previously used for the 21SW152's, so I could get a 2ohm nominal load for the amp. The K20 still current limited well before getting to the driver limits. Not surprising since the minimum impedance is dropping down near 1.5ohms and the amp is rated for 4ohm bridged. Thankfully those amps are so well protected they won't let you blow them up even when you do something stupid. Next time I'm out and going to let one channel of the SP2-12000 have a go at this cab and see if it does any better.

 

I was going to say...try the SP amp :)

 

I've driven my IPALs to what looked like near 3" peak to peak excursion with a SP2-12000!!

Share this post


Link to post
Share on other sites

I was going to say...try the SP amp :)

 

I've driven my IPALs to what looked like near 3" peak to peak excursion with a SP2-12000!!

 

I'm going to try it out. Probably a single channel on both first to see what happens. Remember I'm testing these in about 2.75ft sealed per driver so it takes a lot more power to get them moving versus the Othorn and the average impedance is way lower. If that works out all right I may try both amps in the 12K connected one to each driver. I'm a little worried on that since it's a 1ohm min load on each and the airspace is shared. If one side of the amp protects or limits slightly before the other that could cause a catastrophic instability for the drivers (suddenly becomes a very high tuned PR enclosure in the middle of a very high power measurement. :o )

  • Like 1

Share this post


Link to post
Share on other sites

I'm going to try it out. Probably a single channel on both first to see what happens. Remember I'm testing these in about 2.75ft sealed per driver so it takes a lot more power to get them moving versus the Othorn and the average impedance is way lower. If that works out all right I may try both amps in the 12K connected one to each driver. I'm a little worried on that since it's a 1ohm min load on each and the airspace is shared. If one side of the amp protects or limits slightly before the other that could cause a catastrophic instability for the drivers (suddenly becomes a very high tuned PR enclosure in the middle of a very high power measurement. :o )

 

That sounds like it could get expensive real quick... :wacko: lol

Share this post


Link to post
Share on other sites

Well...2017 season is shaping up to be interesting already. This is just a few of the things that will be on the agenda this year.

 

Alpine Type R 15" sealed. Had this driver ready to go all last year and just didn't get to it.

 

Skhorn cab with dual 21-Ipal. Nuff said.

 

RF T3S2-19 vented in the 21" variable tune cab. Have to make a baffle to downsize the cut-out.

 

B&C 21DS115 testing.

 

Jeff from JTR Speakers will be having a few things tested.

 

I'm trying to get some more pro oriented bass cabinets submitted. I have some leads but we'll see. Fingers crossed.

 

Might try to revisit the M.A.U.L. cab after a year of break in on the drivers and use the SP-12000 amp. The first test was the first time the drivers had seen power. They went straight from the boxes into the cab and out into the field. Would be interesting to see how the suspension softening on the drivers affects the system behavior.

 

There's more...

  • Like 4

Share this post


Link to post
Share on other sites

Any plans to test AE subwoofers or Bill Fitzmaurice bass horns like the table tuba or THT?

 

 

I've unfortunately had issues with my AE TD18's since day one, so they have never made it to high power testing. In fact I've got one with a scraping former right now after working fine for a year or so. Been like that for a few months and I haven't even contacted AE yet because I'm kind of over it. Maybe some day. I already know they are not going to be deep bass, or power handling champions. I really like them when they work, so it's not a big priority to torture test one and potentially have to get it reconed again.

 

I wouldn't mind evaluating a THT or one of the other ones but I'm for sure not going to build one to do so. Someone would have to loan me one for a while and no one has ever offered. Same thing applies to some of the DIYSG flatpacks, McFly subs, or LilMike's designs. I'd do it but I'd need the subs provided to me.

Share this post


Link to post
Share on other sites

I have two used AE IB 15" subs and am toying with the idea of sending you one for testing.Would it be worthwhile even if the Qtc is 1.5 or so in your test box?

 

I imagine I would have to pay shipping both ways, I am located in Minneapolis, MN. What is the chance the sub would survive:) ? 

Share this post


Link to post
Share on other sites

I appreciate the offer but I think it would be better to do one of the other AE drivers. Testing an IB driver in a WAY undersized cab isn't going to flatter it.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×