BOSSOBASS Raptor system 3

[SME]

I also look forward to seeing the results for the HS-24.  Ricci, does your testing routinely bottom subs?  I know you usually try to run the test subs up to but not beyond their limits.  Of course, it looks like most people are pairing these with smaller boxes where over-excursion less likely, even with a K-20.

 

I know some here would argue that the power compression and distortion measurements are not very relevant to performance with real world content, but I'm actually curious about those results.  Will the HS-24 (in a big sealed box) exhibit more linearity as it approaches Xmax versus multiple 15s and 18s?  I know earlier in this thread, Dave said something to the effect that it was the best woofer he'd heard.  I'm not sure if he meant that 1 x 24" sounds better than 4 x 15s or 2 x 18s or whether he's thinking about what 4 x dual-opposed 24" modules would do for his space.  If the 24" really sounds better than 2 x 18s or 4 x 15s, then I reckon the improvement would be due to decreased compression and/or distortion, to the extent that it contributes to the subjective impression of the sound.  I won't comment on the absurdity of running 8 x 24" woofers with 20 cuft each in any residential size installation.

 

Otherwise, I don't see a clear benefit for using the 24"s in most cases.  The simulated performance of 1 x HS-24 against 2 x HST-18s suggests that the HS-24 has slightly less than double the displacement at more than double the cost (list price) and with considerably reduced efficiency in terms of watts and box volume needed to achieve the same displacement.  OTOH, as an IB sub this might achieve a decently flat in-room response without using any signal shaping and would have very modest power requirements doing so.  This might appeal to a few DIYs who are eager to get away with using cheaper amps and who have the required space to do it.  Maybe large scale installations might benefit too?

 

I also have to admit that the sub is stunning to look at.  For the most part, my appreciation of the appearance of woofers ranges from neutral to negative, but the HS-24 is beautiful in its pictures.  To the extent that subwoofers function as furniture, the HS-24 has a real edge.  There's a part of me that wants those woofers in my house.  The problem is that I just don't have the space.  My current plan is to run an A-14k through two pairs of dual-opposed HST-18s.  I can build boxes only slightly larger than my current LLTs and get a huge upgrade in capability.  To get the same performance out of HS-24s, I'd need to give up the dual-opposed design and build boxes with a much bigger footprint than I can really deal with.  Or I can indulge my visual sense while accepting reduced performance (and possibly subs that behave like washing machines when running full tilt) from 2 x HS-24s in boxes too small.

[Madaeel]

Remember this is a 24" IB subwoofer. I would stick with a large sealed but if porting try 75cuft 12hz tune.

 

 

Bosso why does the Clone have a lower cutoff than your amp?

 

I dont want to be a part of this argument just curious is all. I am sure we can count on consistent production amps from you verse the many clone builders.

 

 

 

And beast what Crest amp were you using?

So you don't see the humor in a sealed sub needing 15-20cuft?? I know it's a 24" driver. Regardless if it's an IB sub or not, at that size you'd be better off doing multiple 18's even with it's displacement capabilities. Don't get me wrong the 24 is one badass sub but that is one massive box for a sealed sub. Not to mention even though one should have enough output for most guys you still would need two for most rooms for smoothing. That's a LOT of floor space.

 

As far as the amps go IIRC Dave said some of the clones had very little roll off but they just weren't consistent from one amp to another.

 

SME was thinking the same thing as me. I do agree with him though I'd love to have or hear one too.

[chrapladm]

Your fat.......sarcasm.

 

Sorry its so hard to tell if some one is in a jocular mood or not. And yes it is comical for the sheer size you need to have one sealed. Thats why I went the 15 route.

[3ll3d00d]

I want to try to load the cal files but I am confused.  I tried using curve editor but that does not work with windows 8 and that would have been so easy to do. 

I've attached a filter for you, I had to rename it to txt to be able to attach it (and I couldn't reply to the PM as the forum software blew up when I tried to post it inline) so just rename this so the extension is FRS not txt and then follow the instructions for loading the filter in http://data-bass.ipbhost.com/index.php?/topic/290-using-speclab-for-measuring-in-room/

mktheater_cal_filter.txt

[MKtheater]

I love using one monster amp over many less powerful amps myself. It have had better low end this way.

[theJman]

I also have to admit that the sub is stunning to look at.  For the most part, my appreciation of the appearance of woofers ranges from neutral to negative, but the HS-24 is beautiful in its pictures.  To the extent that subwoofers function as furniture, the HS-24 has a real edge.  There's a part of me that wants those woofers in my house.  The problem is that I just don't have the space.  My current plan is to run an A-14k through two pairs of dual-opposed HST-18s.  I can build boxes only slightly larger than my current LLTs and get a huge upgrade in capability.  To get the same performance out of HS-24s, I'd need to give up the dual-opposed design and build boxes with a much bigger footprint than I can really deal with.  Or I can indulge my visual sense while accepting reduced performance (and possibly subs that behave like washing machines when running full tilt) from 2 x HS-24s in boxes too small.

Have you seen the subwoofers from Deep Sea Sound?  They use the SI24 (and the 18) in their products, so for those who don't necessarily want to go the DIY route an option now exists.

 

{note: if posting a link to another subwoofer is considered a breach of forum protocol please feel free to delete this}

[Bossobass Dave]

So you don't see the humor in a sealed sub needing 15-20cuft?? I know it's a 24" driver. Regardless if it's an IB sub or not, at that size you'd be better off doing multiple 18's even with it's displacement capabilities. Don't get me wrong the 24 is one badass sub but that is one massive box for a sealed sub. Not to mention even though one should have enough output for most guys you still would need two for most rooms for smoothing. That's a LOT of floor space.

 

As far as the amps go IIRC Dave said some of the clones had very little roll off but they just weren't consistent from one amp to another.

 

SME was thinking the same thing as me. I do agree with him though I'd love to have or hear one too.

 

This ^^^

 

I love the driver. It's a masterpiece. But, IMO, the larger the long-throw, the more you need a dual opposed driver configuration. The box size to too prohibitive. Yes., like the LLT. Who cares what the benefits to a sub are if the box is bigger than your refrigerator?

 

On the amp thing, no one tests amplifiers with signal input to 1 Hz, like we do with L/T'd sealed systems and WOTW the minute we plug the sub in. Pro amps have been rated from 20-20k Hz since Fred Flintstone worked for Mr. Slate. There's a reason they don't quote anything <20 Hz. So, what good is an amplifier that's flat to DC if it trips a protect circuit or shuts down every time you play the scenes you built your sub to experience playback of? Pretty much, zero, IMO... YMMV. Some of the clones I used had a shallower roll off, but they also had a 50% failure rate.

 

We're experimenting with roll off options, but so far, the one we have is a reliably good average. It's better to look at the upstream signal chain roll off than to indiscriminately mess with roll off only of your amplifier. Changing it would best be done on an individual basis, as every signal chain is different and that changes every year with new hardware.

 

The world is full of amplifiers and subwoofer options. People can yak away about those options with all sorts of know how and, frankly, nonsense, but I see no posted real world results that match ours, let alone best them.

[Ricci]

 

On the amp thing, no one tests amplifiers with signal input to 1 Hz, like we do with L/T'd sealed systems and WOTW the minute we plug the sub in. Pro amps have been rated from 20-20k Hz since Fred Flintstone worked for Mr. Slate.

 

Not super relevant, but just as an FYI I start all of the measurements taken in REW at the bottom which is 2Hz. The output compression sweeps are 2-120Hz for example. I don't show the data below 10Hz because outdoors virtually no systems have the headroom to get up out of the noise floor enough for a useful comparison of data that low. The reason this is done, even though the data that low is not presented, is in order to fully tax the driver excursion of the system being tested.

 

 

SME

I do not purposely bottom drivers or burn them up either. However with something like the 24 a lot of speculation and claims have been made about it. In cases like that I make sure the limits are found. The driver is fine but I did make it make an obvious mechanical noise twice with CEA-2010 testing. Yes this happens occasionally. With CEA-2010 you can adjust the signal by 0.1dB degrees so by slowly nudging it up it is easy to find the point where the driver goes from "ok" to "STOP!". What usually happens is the system will remain very clean near an impedance peak and you'll actually bottom the driver before reaching the distortion thresholds. A few small taps with these burst signals is usually not damaging to the drivers. If that type of thing happens during a output compression sweep it is usually game over.

 

I'll start a thread for the 24" discussion so we can find it later and not have it buried pages deep in Dave's.

[Bossobass Dave]

Not super relevant, but just as an FYI I start all of the measurements taken in REW at the bottom which is 2Hz. The output compression sweeps are 2-120Hz for example. I don't show the data below 10Hz because outdoors virtually no systems have the headroom to get up out of the noise floor enough for a useful comparison of data that low. The reason this is done, even though the data that low is not presented, is in order to fully tax the driver excursion of the system being tested.

 

I'll start a thread for the 24" discussion so we can find it later and not have it buried pages deep in Dave's.

 

I did not know that. Interesting. As you say, it's only relevant to your signal chain and the K-10/K-20 on a 220V-50A dedicated line. This metric, however, makes testing any other amplifier vs the Powersoft stuff with the same regiment even more interesting.

 

A related FYI, REW sweeps are linear from 2-10 Hz and log after that. And, you'll have to post a loopback of the signal chain FR.

[BeastAudio]

Remember this is a 24" IB subwoofer. I would stick with a large sealed but if porting try 75cuft 12hz tune.

 

 

Bosso why does the Clone have a lower cutoff than your amp?

 

I dont want to be a part of this argument just curious is all. I am sure we can count on consistent production amps from you verse the many clone builders.

 

 

 

And beast what Crest amp were you using?

 

 

The 7.5

[3ll3d00d]

another FYI is that REW sweeps actually start and end 1 octave below/above the range you enter though I'm unsure whether there is a difference in behaviour when you start at 2Hz though (you can see it changes the text to "from DC" when you go low enough), not sure if this makes any difference to you but thought I'd mention it

[Madaeel]

Your fat.......sarcasm.

 

Sorry its so hard to tell if some one is in a jocular mood or not. And yes it is comical for the sheer size you need to have one sealed. Thats why I went the 15 route.

Man FUCK you! I almost spit out my coffee when I read that hahaha. Its funny cuz its true.

 

Have you seen the subwoofers from Deep Sea Sound?  They use the SI24 (and the 18) in their products, so for those who don't necessarily want to go the DIY route an option now exists.

 

{note: if posting a link to another subwoofer is considered a breach of forum protocol please feel free to delete this}

Yah I saw those too and while that's pretty cool someone is doing an ID version of the 24 they're in a cab half the size that's recommended so how much are you losing down low to have a cab that's manageable. Not to mention the price....

 

I posted a link to AVS so I don't think that's a problem but better to post it in it's own thread when Josh puts up the measurements.

[theJman]

Yah I saw those too and while that's pretty cool someone is doing an ID version of the 24 they're in a cab half the size that's recommended so how much are you losing down low to have a cab that's manageable. Not to mention the price....

I noticed that as well.  There's probably a lot of DPS programming going on there, eh?.  However, relative to the cabinet Brandon built those Deep Sea subs almost look like Sunfires!

[Madaeel]

I noticed that as well.  There's probably a lot of DPS programming going on there, eh?.  However, relative to the cabinet Brandon built those Deep Sea subs almost look like Sunfires!

Haha yah they do. Now I'm curious once Josh puts up the numbers if he can get a DSS sub and compare the numbers down low to see how much a difference his amp and box makes.

[SME]

another FYI is that REW sweeps actually start and end 1 octave below/above the range you enter though I'm unsure whether there is a difference in behaviour when you start at 2Hz though (you can see it changes the text to "from DC" when you go low enough), not sure if this makes any difference to you but thought I'd mention it

Does it actually start one octave lower?  I thought it only ended one octave (or so) higher, and only did so when the stop frequency is less than one octave (or so) below 1/2 the sample rate.

 

I actually investigated this feature in some detail because I ran into a problem with my own sine sweep measurements in which I needed to truncate the data somewhere before the sweep stop (but not at any low frequency) in order to avoid basically dividing by zero.  Of course, just cutting off the data is like applying a sinc filter that leads to lots of time domain ringing in the impulse response, so I had to intelligently develop a filter that depends on the sweep stop frequency.  I never figured out exactly how REW handles this.

[Madaeel]

Dave one of your favorites(and Matt's )....Oz tornado scene:

 

 

James you run this one yet?

[3ll3d00d]

Does it actually start one octave lower?  I thought it only ended one octave (or so) higher, and only did so when the stop frequency is less than one octave (or so) below 1/2 the sample rate.

 

I actually investigated this feature in some detail because I ran into a problem with my own sine sweep measurements in which I needed to truncate the data somewhere before the sweep stop (but not at any low frequency) in order to avoid basically dividing by zero.  Of course, just cutting off the data is like applying a sinc filter that leads to lots of time domain ringing in the impulse response, so I had to intelligently develop a filter that depends on the sweep stop frequency.  I never figured out exactly how REW handles this.

I don't know if there is some variation in the behaviour under certain conditions, I am basically just quoting JohnM above from http://www.hometheatershack.com/forums/rew-forum/120402-measurement-sweep-range-accurate-response.html#post1183906

[SME]

Have you seen the subwoofers from Deep Sea Sound?  They use the SI24 (and the 18) in their products, so for those who don't necessarily want to go the DIY route an option now exists.

 

{note: if posting a link to another subwoofer is considered a breach of forum protocol please feel free to delete this}

Yep.  Good to see that the prices and specs are up now.

 

But I'm still planning to go DIY instead.

[Madaeel]

And the end fight scene:

 

 

[SME]

I don't know if there is some variation in the behaviour under certain conditions, I am basically just quoting JohnM above from http://www.hometheatershack.com/forums/rew-forum/120402-measurement-sweep-range-accurate-response.html#post1183906

Well, I gather you're right then being that JohnM is the author.  I wonder if he's applying an HPF to the results as well as a LPF?

[Madaeel]

Hey guys do me a favor and take the REW talk to another thread. I appreciate your contributions but this thread is always going off topic. Thanks.

[STL D]

I noticed that as well.  There's probably a lot of DPS programming going on there, eh?.  However, relative to the cabinet Brandon built those Deep Sea subs almost look like Sunfires!

 

A 4000 watt amp gives plenty of EQ wiggle room down low. 

[BeastAudio]

Man you! I almost spit out my coffee when I read that hahaha. Its funny cuz its true.

 

Yah I saw those too and while that's pretty cool someone is doing an ID version of the 24 they're in a cab half the size that's recommended so how much are you losing down low to have a cab that's manageable. Not to mention the price....

 

I posted a link to AVS so I don't think that's a problem but better to post it in it's own thread when Josh puts up the measurements.

 

David has done the work in the DSP of the amp that gets these to extend down low and overcome the box size. In my case, I wanted my box to be big enough we didn't necessarily need any DSP, although even at 17 cuft, some work on the rolloff would have still been warranted. 

 

 

Haha yah they do. Now I'm curious once Josh puts up the numbers if he can get a DSS sub and compare the numbers down low to see how much a difference his amp and box makes.

 

 

This is the plan in the near future. I think some folks will be surprised. As far as the price goes, this sub, for $4,000 is unbeatbale for an ID/ plug and play option. 

[Ricci]

Correct on the REW info. I've done a LOT of dickering with exported text files. Also you need a measurement that covers the harmonic of interest multiplied by the upper bandwidth of interest in order to record distortion results. And REW will extend an octave higher as usual as well.

So the THD measurements I use are 2-2000Hz which covers 2-200Hz up to the 10th harmonic. The actual signal fed the speaker extends to 4kHz.

[Madaeel]

this sub, for $4,000 is unbeatbale for an ID/ plug and play option. 

And it should be for $4k. Problem is most people will need two. $8k for 30L is a little steep. Though when compared to Funk this is a bargain.