Stereo Integrity SHS-24 Testing & Discussion

[Ricci]

Notes and free-air specs for these gigantic 24" drivers have been posted under the driver page. 

These weigh in at a back straining 115lbs and are capable of 4" peak to peak. 

Beef it's what's for dinner

[EndersShadow]

Looking forward to your testing on this beast.....

I've always been shocked at the performance of these drivers.

Wish I could fit 21's or 24's in my space (without needing a divorce lawyer, or contractor to build a bump out for my family room)

[Kyle]

This driver is nuts! 

I need to see this thing run against the 24vU https://www.harbottleaudio.com/24vu.html

[Infrasonic]

Woah nelly! 

 

I can't forget experiencing TWO of these in a van back when Nick had just released them. These drivers are HULK-like!

[tktran303]

Are they NLA?

[Ricci]

On 9/13/2019 at 11:26 PM, tktran303 said:

Are they NLA?

What does NLA mean? 

[SME]

I think it means "no longer available".  I don't have answer to the question though.

[Ricci]

Ahhhh. I think you're right.

Unfortunately according to the SI website that may be the case for these drivers, which is a shame. I wonder how many were sold at the sale price last holiday season. Perhaps it'll be a small batch as requested type of deal. 

I need to get my ass in gear and figure out what type of cabs I'm going to build to test these. I still have the giant sealed cab from the original HS-24 testing. I'm tempted to see if I can somehow cram 2 or 3, 6" aero-ports in that cab without too much trouble. 

[Ricci]

[EndersShadow]

Looks like double the fun....... or do we have two different versions?

[peniku8]

I remember reading about a clearout sale a few months ago. The SHS would become NLA after that according to the website.

[Ricci]

I'm assuming sales were slow at the prices these went for. I haven't seen anyone else on the forums post about having an SHS-24. I figured a few would've been bought during the closeout sale.

I always get at least a pair of drivers. 

[BBLV]

@Ricci Did you ever design and/or build enclosures for these? I have two sitting here waiting for time to start cutting wood and was hoping to compare notes.

[BBLV]

FYI mine are dual 1 ohm coils and will be running on an SP2-12000 amp. I'm using the T/S parameters emailed directly to me from Nick for WinISD. I've modeled the following ginormous enclosure for each sub. These will be against the back wall of my 17.5'W x 26'D x 9'H dedicated theater room where the cone will be about 5' behind the back row of seats and 10' behind the front row. The plan is for these to handle ~10 to 45Hz where my LCR speakers will takeover (DIYSG dual woofer Titans).

• Box: 30cf @ 12Hz
• Vent: 30"W x 4.5"H x 66.5"L
• 1st Port Res: 96.93Hz
• Rear Port Air Velocity: ~29.5 m/s max @ 11.5Hz
• Cone Excursion: 36.6mm @ 10.4Hz
• Filter: HP BW4 @ 11Hz
• Input Power: 6000w

I was trying to increase the port area to lower the port velocity and increase SPL/cone excursion, but the 1st port resonance was dropping too low for comfort. I think this is a decent happy medium - I'd obviously love to get a little more SPL and utilize ~10mm more xmax. Thoughts on how to get there without creating port chuffing/resonance issues?

[Ricci]

I've been thinking about this myself. The SHS-24 is a tough driver to tune really low and port well. It moves a ton of air but it doesn't really call for a very big enclosure for a smooth response. Big air spaces cause a large peak at the port tuning. It's difficult to get enough power on it to effectively use the excursion also. 

It really depends on your goals and how much you are willing to compromise. 

The cab you've specified is about 850L with a vent area of about 871cm and a vent length of 169cm. Tuning is around 12.2Hz. Personally I would not use a vent that long. It puts the vent resonance down below 100Hz. My limit on port length I generally set at 40" or 102cm which puts vent resonance at about 150Hz and a half octave above the typical sub LPF. It will greatly decrease your port area though. If you want to increase driver excursion, tuning lower helps  but again this either increases vent length or decreases area. 

If it were me and I was willing to go that big I'd go ahead and tune the cab to almost 10Hz by cutting the vent size way back to a length of 102cm / 40" and drop the area to roughly 363cm which would be equivalent to two 6" Aeroports. You will lose some output from 12-20Hz but it's not as much as you would think. Only a few dB. Airspeed gets really high at 10Hz but should be decent at maximum output above 12Hz. You gain extra extension and output below the original tune, the vent resonance gets pushed up to about 150Hz and the overall size of the system is reduced by about 13%. Don't forget that in a typical home listening environment room gain kicks in and by the 10-14Hz range it is not uncommon to have 10dB of gain. You will likely have to cut back the peak at tune and the low end in general or it could sound overwhelmingly bottom heavy. HR modeling with specs measured from my SHS-24's including complex inductance shows about an 8dB peak at port tuning. Add in roughly 10dB of room gain and you can see where this frequency bandwidth is likely going to need some EQ. Also content at maximum level down below 14Hz is really rare. I don't think you will be running a pair of these at full output at those frequencies very often. It will do things to your home and furnishings. I know from experience. What I'm saying here is I don't feel like all of the extra sacrifices that are caused by making the ports such a large area and length, are worth it for a few dB more output that is unlikely to be called on much, both from an output standpoint and a frequency bandwidth standpoint. Even with greatly reduced port area it should be more than enough for any sane playback level you'll be using in your home. 

I'm probably going with a 425L ported cab with half the vent area of what is proposed above. The size of the system will also be half of the above though. 

It's easy to see why most people go sealed or IB with the 24's. Simply put it in a 26" cube and it'll perform very well. No worrying about vent tunings, port velocity, resonances and it's a fraction of the total size. 

 

[dgage]

My sealed HS-24 based subs are flat in-room to 7 Hz at reference.  7 Hz has been measured in over a dozen rooms at this point and one room was flat to 6 Hz as the sub was corner-loaded with 2 exterior walls.  So there is something to be said for Josh’s recommendation of a simple sealed enclosure for these subs.  Yes you lose some 25+ Hz output compared to the efficiency of ported but below 20-25Hz, the sealed should have more output isn’t a Linkwitz Transfrom.  Multiple subs would be needed to make up for the porting efficiency but that would be worthwhile for more even bass response anyway.

[Ricci]

3 hours ago, BBLV said:

 

 

 

Hey man...Unfortunately what you would be building would be nothing like the winisd sim...

You are looking more at something like this. 

 

 

[BBLV]

1 hour ago, Ricci said:

Hey man...Unfortunately what you would be building would be nothing like the winisd sim...

Good looking out! 😂 I owe you a beer (or three).

I'm not very experienced in the model vs real world translation, so I guess I'll sit by and wait for more details on your enclosure and build accordingly in the 15cf range. The last thing I want to do is to spend the time and effort building these boxes and them sound like shit.

[BBLV]

Regarding a sealed enclosure, I've seen mention of 3cf but feel that would just be awkward in my theater room. Do I lose anything going to ~10-12cf sealed?

[Ricci]

Here are a few comparisons. 

This is still using the big 850L enclosure but cutting down the vent length and area and tuning to 10Hz. Light grey line is your original plan. Once you add room gain to this that peak at port tune is going to be WAY too hot. It'll have to be addressed with the HPF and EQ to cut it back anyway or anything that hits that narrow frequency range is going to be heavily boosted relative to everything else. Also this is just an absolutely huge cabinet. Outer volume will probably be approaching 40 cu ft on your original plan.  

 

 

This is similar to what I will probably go with. 425L tuned to 10Hz with multiple vents for different higher tuning options. This is literally half the size of your original plan. Still a very big sub but quite a bit more manageable by 2 people. Yes it gives up some output below 20Hz but relative to the huge size disadvantage it's not that much. This is with the 10Hz tuning. This would work a lot better with typical room gain, but still might require a bit of a cut at 10Hz. 

 

 

This is the same 425L cab with 2X the vents from the 10Hz sim which would raise the tuning to around 14.5Hz. As you can see this compares very well with your original plan that is 2X the size, which is indicated by the light grey line. 

 

 

Sealed is the easiest option. Anything from 200L to 400L per driver should work. Bigger allows the driver to use more excursion with less power. Even at 400L the SHS-24 should be safe from bottoming with an SP1-6000 but it would be getting close. 300L is probably a good intermediary. I'd not recommend something as small as 3cu ft (85L) Even the full output from an SP1-6000 would not push the driver to 20mm excursion. Heat would be a very real enemy in a cab that small. 

[dgage]

2 hours ago, BBLV said:

Regarding a sealed enclosure, I've seen mention of 3cf but feel that would just be awkward in my theater room. Do I lose anything going to ~10-12cf sealed?

No way the 24 would work well in 3 cf, my guess is you’re getting the 18 confused as that works well in 3-4 cf.  For the 24, I wouldn’t go smaller than 8 cf and you do get a little lower extension going 10-12 cf, which would be my recommendation.  Then again, I usually recommend to my customers multiple 18s over a single 24 for more even bass response in the room. It I think you already have the 24s.

[BBLV]

2 minutes ago, dgage said:

No way the 24 would work well in 3 cf, my guess is you’re getting the 18. Infused as that works well in 3-4 cf.  for the 24, I wouldn’t go smaller than 8 cf and you do get a little lower extension going 10-12 cf, which would be my recommendation.  Then again, I usually recommend to my customers multiple 18s over a single 24 for more even bass response in the room. It I think you already have the 24s.

Yes, I already have two dual 1-ohm SHS-24's sitting here begging to crack my triple layered drywall 😎

[dgage]

Just now, BBLV said:

Yes, I already have two dual 1-ohm SHS-24's sitting here begging to crack my triple layered drywall 😎

Then get cracking.  Lol!

[BBLV]

Here are WinISD max SPL and cone excursion plots of sealed enclosures at 4cf, 10cf and 12cf with 6000w of input for comparison's sake.

[dgage]

My commercial subs are just under 9 cf with 4,000w continuous and like I said, flat to 7 Hz with a Linkwitz Transform and room gain.  So 10-12cf should give you plenty of low-end output but not as much above 40 as if you went ported but the 40+ Hz would really only be usable in venues as they’d be too loud for a home theater in my opinion.  So the sealed 10-12 cf is straight forward and a proven performer while not being TOO big.