Help comparing subs and understanding graphs

[Brewjitsu]

Ok so I am struggling to understand the graphs that are on here and companies web sites about the subs frequency response.

 

Basically I'm trying to compare two different subs and see if they will both do what I want.

 

My room is 5400^3 open plan. Seating position is 12feet from sub. Sub will be in front corner very close to walls.

Listening volumes are between -30 to -15 but generally -20. When I used my spl meter app on my phone it registered approx 75 db when I was at -15.

90/10 movies/music.

Only going to be a single sub not looking to add one later.

 

The subs I am currently trying to compare are the funk audio 18.0c (graphs on this site are the old model Nathan says it performs the same as the 18.0 which is on this site but -2 db accross the graph)

The other sub is PSA v1800 which only has data from their web site.

Size is an issue that's why i would prefer the funk plus I like the dsp on the amp for the funk.

 

Is the data that psa provide likely to be the same as what is on this site ie can I trust their data results? Can someone look at the graphs for both and tell me whether at my listening volumes are they both going to provide me enough bass down to around 20hz?

 

I know I'm comparing sealed with ported but at my listening volumes would I notice any difference between the two?

[tuxedocivic]

Surprised nobody has answered this. I don't think you should compare the graphs from a commercial site. Chances are they have put a favorable lighting on them. Also unless they detail exactly how they measure, they may not be comparable. Ricci gives these subwoofers a real work out.

[Ricci]

I would agree. Always remember that any commercial company is selling something. That doesn't mean that their data or measurements are faulty or inaccurate by any means but at the end of the day they are in the business of selling a product. PSA  are a respected well established company but I don't recommend comparing the measurements here directly to ANY other sources regardless of what company, publication, or reviewer, PSA or otherwise.

 

As far as the comparison between the V1800 and the Funk Audio FW18.0C goes it is an apples to oranges comparison to some extent. The V1800 is about 65% larger if not more and is a vented subwoofer. It's also about half the cost of the Fw18.0C. It is likely to have stronger bass around the vent tuning and a bit above. Likely to be 16-25Hz give or take. The FW18.0c probably has similar or higher output above in the top octaves of its bandwidth and should have better ultimate extension being a sealed design without a high pass filter. It is much smaller and the cabinet finish, materials and the driver are much more expensive and high end pieces. (Note:  It looks like the current FW18.0C is using the TSADv1 driver which is the same as the one used in the FW18.0 tests conducted here. It is not the driver that was used in the FW18.0C tests here. As a result the performance is likely to be better in the low bass range than what was tested for the previous version. ) Both should be well engineered subs but the goals and design approaches for each are quite a bit different.

[Brewjitsu]

I would agree. Always remember that any commercial company is selling something. That doesn't mean that their data or measurements are faulty or inaccurate by any means but at the end of the day they are in the business of selling a product. PSA  are a respected well established company but I don't recommend comparing the measurements here directly to ANY other sources regardless of what company, publication, or reviewer, PSA or otherwise.

 

As far as the comparison between the V1800 and the Funk Audio FW18.0C goes it is an apples to oranges comparison to some extent. The V1800 is about 65% larger if not more and is a vented subwoofer. It's also about half the cost of the Fw18.0C. It is likely to have stronger bass around the vent tuning and a bit above. Likely to be 16-25Hz give or take. The FW18.0c probably has similar or higher output above in the top octaves of its bandwidth and should have better ultimate extension being a sealed design without a high pass filter. It is much smaller and the cabinet finish, materials and the driver are much more expensive and high end pieces. (Note:  It looks like the current FW18.0C is using the TSADv1 driver which is the same as the one used in the FW18.0 tests conducted here. It is not the driver that was used in the FW18.0C tests here. As a result the performance is likely to be better in the low bass range than what was tested for the previous version. ) Both should be well engineered subs but the goals and design approaches for each are quite a bit different.

I understand the apples oranges comparison. I like the size of the funk and the amp and am happy to spend the money on it I guess I'm just curious to get someone's opinion such as yourself who knows a lot more than I do as to whether at my -15 reference levels approx 75db if you think the 18.0c is capable of delivering sufficient bass down to 20hz or below in a 5400^3 room or if I really do need to look at a larger sub and or ported sub?

Thanks for your response above.

[Brewjitsu]

I would agree. Always remember that any commercial company is selling something. That doesn't mean that their data or measurements are faulty or inaccurate by any means but at the end of the day they are in the business of selling a product. PSA  are a respected well established company but I don't recommend comparing the measurements here directly to ANY other sources regardless of what company, publication, or reviewer, PSA or otherwise.

 

As far as the comparison between the V1800 and the Funk Audio FW18.0C goes it is an apples to oranges comparison to some extent. The V1800 is about 65% larger if not more and is a vented subwoofer. It's also about half the cost of the Fw18.0C. It is likely to have stronger bass around the vent tuning and a bit above. Likely to be 16-25Hz give or take. The FW18.0c probably has similar or higher output above in the top octaves of its bandwidth and should have better ultimate extension being a sealed design without a high pass filter. It is much smaller and the cabinet finish, materials and the driver are much more expensive and high end pieces. (Note:  It looks like the current FW18.0C is using the TSADv1 driver which is the same as the one used in the FW18.0 tests conducted here. It is not the driver that was used in the FW18.0C tests here. As a result the performance is likely to be better in the low bass range than what was tested for the previous version. ) Both should be well engineered subs but the goals and design approaches for each are quite a bit different.

Yes Nathan mentioned the new 18.0c should be similar to the 18.0 but down about 2db accross the graph.

[muzz]

That's a pretty big room for a pretty small sealed sub.

75 isn't much though.

Others with far more sealed experience than I will chime in I'm sure.

[SME]

Unless there's at least some hope of getting another sub in your future, I would vote for the ported option.  Either sub would probably do a good job in your space and chosen listening level.  In fact, if you were willing to consider multiples, placed in opposing corners or some such, I'd suggest getting a pair of somewhat less expensive sealed subs as the benefit of the improved room response is likely to be greater.  However, as far as single subs go, the ported sub ought to be able handle the deeper 15-30 Hz octave with more ease than the sealed in your relatively large room.

 

Don't pay too much attention to amp power.  The difference between 1000W and 725W is trivial.  And anyway, performance depends on a lot more than just power.  The ported sub is probably much more efficient in that 15-30 Hz octave.  Fundamentally speaking, It takes a lot of power to make a woofer in a small box product deep bass, no matter how good the woofer is.  Where the sealed box designs really shine is in smaller rooms and when they are deployed in numbers with signal compensation that allows them to play much lower than even the most outrageously large ported designs can.  A number of people on this site own systems with 2, 4 or 8 sealed subs to achieve reference level in-room performance to 5 Hz or lower.

 

Best of luck to you, whatever you choose.

[Brewjitsu]

Unless there's at least some hope of getting another sub in your future, I would vote for the ported option.  Either sub would probably do a good job in your space and chosen listening level.  In fact, if you were willing to consider multiples, placed in opposing corners or some such, I'd suggest getting a pair of somewhat less expensive sealed subs as the benefit of the improved room response is likely to be greater.  However, as far as single subs go, the ported sub ought to be able handle the deeper 15-30 Hz octave with more ease than the sealed in your relatively large room.

 

Don't pay too much attention to amp power.  The difference between 1000W and 725W is trivial.  And anyway, performance depends on a lot more than just power.  The ported sub is probably much more efficient in that 15-30 Hz octave.  Fundamentally speaking, It takes a lot of power to make a woofer in a small box product deep bass, no matter how good the woofer is.  Where the sealed box designs really shine is in smaller rooms and when they are deployed in numbers with signal compensation that allows them to play much lower than even the most outrageously large ported designs can.  A number of people on this site own systems with 2, 4 or 8 sealed subs to achieve reference level in-room performance to 5 Hz or lower.

 

Best of luck to you, whatever you choose.

So you think the funk would be adequate at my listening levels in my room? Do you think it can get below 20hz with enough db to feel it in my room? Unfortunately 1 sub has to be enough I won't be getting another later down the track. I like the amp not for its size but because it's full dsp.

[Ricci]

That's a big room. Your listening habits are -15 from REF and with the sub set flat I would assume? If you are running 7.1 a worst case signal to the subwoofer could require it to produce about 110dB to your headrest with the loudest brief signals. That's a tall order from a single compact sealed sub in a room that size. If you can only fit a single sub I would suggest the largest most powerful one that will fit for you and stays in budget. Both of the subs that you have proposed are likely very good subs but have you considered other brands and models?

[Brewjitsu]

That's a big room. Your listening habits are -15 from REF and with the sub set flat I would assume? If you are running 7.1 a worst case signal to the subwoofer could require it to produce about 110dB to your headrest with the loudest brief signals. That's a tall order from a single compact sealed sub in a room that size. If you can only fit a single sub I would suggest the largest most powerful one that will fit for you and stays in budget. Both of the subs that you have proposed are likely very good subs but have you considered other brands and models?

 

Thanks for the response.

Being in Australia I have access locally to Rythmik, PSA and SVS. I have been communicating with Funk, Deep Sea Sound and Reaction Audio as well. Deep Sea is out of my budget unfortunately freight and a bad dollar makes all options pretty expensive.

My stipulation is I really dont want to go any bigger than the V1800. I have been discussing the Gamma21 with the 3200w amp with Jeremy which I think would be the best performance of any I have been looking at? He also has a new Gamma18 coming with new driver and 1400w.

Im running 5.1

Very interested in your thoughts on other subs to the 2 I have mentioned. 

So you dont think a sealed 18" is up to the task at my listening levels? I just dont know if I am getting caught up in all this because if I take some peoples advice I would end up with stacks of subs. I will only have 1 sub and want to have a great movie experience.

Greatly appreciate everyones thoughts and advice.

[SME]

So you think the funk would be adequate at my listening levels in my room? Do you think it can get below 20hz with enough db to feel it in my room? Unfortunately 1 sub has to be enough I won't be getting another later down the track. I like the amp not for its size but because it's full dsp.

Loud enough to feel bass below 20 Hz?  Probably.  But not necessarily any more than that.  What you actually hear depends on what the natural response of the sub looks like and how your room and where you sit affects that response.  Unless there is some EQ used somewhere, most sealed subs have a response that starts to drop off somewhere in the 30-50 Hz range.  Although EQ can boost the response below, that extra output demands more power and excursion from the woofer, so it's more likely to be overloaded.

 

I will add that I agree with Ricci in the sense that for optimal performance, you really want more capability if you can get it.  However, as you put it, a stack of subs is not something you are entertaining right now.  Either sub will likely give you good but not great performance in that space, but because of your room size and your interest in deep bass (20 Hz and below), I think the ported will give you more of what you are looking for.

 

If you are willing to consider other things, are you primarily concerned about weight or physical dimensions?  If you're willing to go a tad bigger than the V1800, you could consider something like this from JTR.

[Brewjitsu]

Thank you SME your comments are helpful. Size is my concern not weight and the JTR is getting very big and expensive by the time I convert to Australian dollars and pay tax and freight its approx 50% more.

 

What are peoples thoughts on the reaction audio Gamma 21? Its maybe passable size wise and its within budget. I know, I know its sealed but it looks like it could out perform any of the sealed 18" subs in the market place especially with the 3200w amp that is required to be compatible in Australia. Size is slightly bigger than what I want but I think it could offer the performance required for the area. Any one want to offer there thoughts.

[Ricci]

Being in Australia that does change things a bit. I was going to suggest looking at the JTR Captivator. It offers a lot of power for its size but it appears the conversion and shipping kills the price. The other thought I had was a sub from Deep Sea Sound since their subs are really powerful for having a single driver but those are out too. I too think it makes more sense for a vented sub in your case. Doesn't Reaction audio have a couple of vented models?

[Bossobass Dave]

The OP gives a choice of 2 subs and invariably gets suggestions for every sub but one of the two subs presented.

 

Making sure I have the right comparo?

 

 

I would personally use Josh's test results of the Chase vented 18 because:

 

The PSA version is tuned lower than the Chase version and uses obvious EQ to alter the natural response whereas the Chase does not, but, as all of the suggestions will point out, the bottom line in any differences between the 2 subs in the OP's choices will be those at maximum output because of room size, LP distance, penchant for high dBSPL amongst members, etc. That means the PSA will show port compression and reversion to native response when pushed to its limits and the 2 subs will show similar end results, IMO. They both use almost identical drivers. One has a bit more amp but smaller box. They're both available in butt-ugly black.

 

The differences between the Funk and the PSA will be classic regarding performance when referenced in the context of the decades-old ported vs sealed debates. There will be some output advantage across 1 octave, centered at the ported sub's tune and there will be nothing but noise below that and the sealed sub will exhibit the corresponding deficit around the ported sub's tune but offer usable output to single digits.

 

That doesn't account for the vastly superior cabinetry and finish work by Nathan Funk and the much better driver and more powerful amplifier. This is where my opinion has always (and always will) tip the scales in any such choice. The Funk sub is truly furniture grade and awfully swell to look at and the PSA is a standard pro sound black pebble box.

 

Here's an animation showing the THD comparo with a graph showing the max sweep and max burst comparos. There will be howls and jeers from the peanut gallery promising the superiority/huge differences between the Chase vs PSA ported 18" versions and vice versa, as usual, but... meh... this is my opinion which is always available to be proven wrong.

 

 

My opinion is always biased toward the better product. Funk builds great subs that look great and perform well. This one is a no-brainer. Although it won't accomplish reference level with the sub at +18dB hot like most here prefer, the Funk 1 x 18" sub will offer far more accurate reproduction at reduced playback levels than any ported version with a lesser driver and amplification. And, it's stunningly executed in anyone's opinion.

[Brewjitsu]

Being in Australia that does change things a bit. I was going to suggest looking at the JTR Captivator. It offers a lot of power for its size but it appears the conversion and shipping kills the price. The other thought I had was a sub from Deep Sea Sound since their subs are really powerful for having a single driver but those are out too. I too think it makes more sense for a vented sub in your case. Doesn't Reaction audio have a couple of vented models?

 

Hi Ricci yes the JTR is too expensive and big and the DSS too expensive. Reaction Audio do have some vented models but once again they are just getting a bit big for my liking. Their Gamma 21 I am now seriously considering and it sounds like it may offer similar performance around the V1800 port tune but out perform in all other frequencies. Jeremy said it would be hard for an 18" sealed sub to out perform this 21".

[Brewjitsu]

The OP gives a choice of 2 subs and invariably gets suggestions for every sub but one of the two subs presented.

 

Making sure I have the right comparo?

 

 

I would personally use Josh's test results of the Chase vented 18 because:

 

The PSA version is tuned lower than the Chase version and uses obvious EQ to alter the natural response whereas the Chase does not, but, as all of the suggestions will point out, the bottom line in any differences between the 2 subs in the OP's choices will be those at maximum output because of room size, LP distance, penchant for high dBSPL amongst members, etc. That means the PSA will show port compression and reversion to native response when pushed to its limits and the 2 subs will show similar end results, IMO. They both use almost identical drivers. One has a bit more amp but smaller box. They're both available in butt-ugly black.

 

The differences between the Funk and the PSA will be classic regarding performance when referenced in the context of the decades-old ported vs sealed debates. There will be some output advantage across 1 octave, centered at the ported sub's tune and there will be nothing but noise below that and the sealed sub will exhibit the corresponding deficit around the ported sub's tune but offer usable output to single digits.

 

That doesn't account for the vastly superior cabinetry and finish work by Nathan Funk and the much better driver and more powerful amplifier. This is where my opinion has always (and always will) tip the scales in any such choice. The Funk sub is truly furniture grade and awfully swell to look at and the PSA is a standard pro sound black pebble box.

 

Here's an animation showing the THD comparo with a graph showing the max sweep and max burst comparos. There will be howls and jeers from the peanut gallery promising the superiority/huge differences between the Chase vs PSA ported 18" versions and vice versa, as usual, but... meh... this is my opinion which is always available to be proven wrong.

 

 

My opinion is always biased toward the better product. Funk builds great subs that look great and perform well. This one is a no-brainer. Although it won't accomplish reference level with the sub at +18dB hot like most here prefer, the Funk 1 x 18" sub will offer far more accurate reproduction at reduced playback levels than any ported version with a lesser driver and amplification. And, it's stunningly executed in anyone's opinion.

 

 

Thank you for your response Bossobass Dave. I have had to read it a few times to understand it properly or I should say to the best of my abilities because I do struggle with understanding the ins and outs of sub woofers.

Yes you have the correct subs from my original comparison. Basically you are saying you would opt for the Funk due to better quality materials and less THD. That the V1800 would likely have a little more power lower but the Funk would be a little better above that.

 

Question does THD really make much of a difference?

 

Question I know the Gamma 21 is new so there isnt a lot of experience with it or information but to generalize knowing the company Reaction Audio and their other products how would people feel this 21" driver and 3200w in a similarly sized box to the V1800 compare to the V1800 and Funk? The price is right in between the V1800 and Funk so Im happy with that. 

[shadyJ]

What Bossobass left out in his comparison was the sweep levels those distortion charts are done at. Look at the corresponding compression graphs, the Funk is putting out a lot more output for those distortion levels, roughly 5 dB more at the maximum. The quality of the Funk sub is waaaay higher at every single level. This is a no-brainer, get the Funk. The Reaction subs look good too.  

[muzz]

I purposely didn't answer this with my opinion because I knew Dave would chime in with sealed.

My vote was, and still is Ported, because of the volume listened at, and room.

The graphs above are at what voltage? Are we talking WAY above his listening level Dave? You didn't post this info, and I think that has a very definite collaration to the graphs you posted.

If you are gonna post graphs, maybe post graphs that show to reference or somewhat above, these look like well above, which is not what he asked and specifically stated in his post.

[muzz]

I probably missed something, if I did I apologize.

[Bossobass Dave]

I purposely didn't answer this with my opinion because I knew Dave would chime in with sealed.

My vote was, and still is Ported, because of the volume listened at, and room.

The graphs above are at what voltage? Are we talking WAY above his listening level Dave? You didn't post this info, and I think that has a very definite collaration to the graphs you posted.

If you are gonna post graphs, maybe post graphs that show to reference or somewhat above, these look like well above, which is not what he asked and specifically stated in his post.

 

Feel free to specify the voltage or whatever else you think is pertinent, with the corresponding graphs and commentary. I commented on the OP's Q regarding understanding graphs.

 

When you start with a flat response, as the V1800 is designed to present, room gain will cause a bump at 20 Hz and the sub will compress below that at virtually any playback. Below tune, ported subs present noise. THD is shown in one of the metrics of the GP methodology, but below tune the ported sub's driver unloads. I guess most people still don't know what 'unloads' means in 2016.

 

To repeat what I've said for millennia, the sealed sub will present a far more accurate reproduction in-room by any metric... period. Loud and/or loud over one particular octave of bandwidth is a different conversation. Attempting to combine the two is for others to discuss.

[SME]

 

The pictures for the sealed sub are for the FW18, not the FW18C.  If you go and compare the CEA results for the FW18 versus the FW18C, you will see that the FW18C is actually capable of 5 or 6 dB *less* than the FW18

 

Try switching between the THD plot for the FW18C and the Chase VS18.1 instead.  It is not too unreasonable to compare these two plots for THD directly in the 15-50 Hz range because both subs have very similar frequency response profiles.  However, the comparison for THD above is invalid even if you were considering the FW18 instead.  The reason why is that the THD sweeps are done at *constant voltage* and not *constant output*.  Each THD sweep is labelled with the dB produced at 50 Hz only.  To compare THD, you must first compute the difference in response between the frequency of interest (e.g. 15 Hz or 20 Hz) for each sub and 50 Hz.  Then you must add this number (which is usually negative) to the number indicated for the THD sweep to get the actual output at the frequency of interest.

 

In the case of the FW18 with 120 V amp as is in the picture, the response at 20 Hz is -16 dB from 50 Hz for the FW18, so the "120 dB" sweep is only actually producing 104 dB at 20 Hz.  For comparison, the Chase V18.1 response is -10 dB for 20 Hz vs. 50 Hz.  The highest level THD sweep is labelled "105 dB", and the sub is only producing 95 dB.  Unfortunately, it's not useful to compare these two sets of THD plots at all.

 

On the other hand, if you look at the FW18C THD plots instead and note that (unlike the FW18) the FW18C is only -10 dB at 20 Hz versus 50 Hz, you will see that the FW18C actually has 15% distortion versus 2-3% distortion at 20 Hz and 95 dB output.  A competently implemented ported system will usually kick the pants off a sealed system in terms of both output and distortion with similar woofer displacement in the region around the port tuning frequency.

 

As a disclaimer, that Chase looks to be a very well implemented ported system, except for the fact that it may not be rolled off aggressively enough below 15 Hz.  Without measurements of the PSA V1800, it's hard to say whether it will perform similarly, better, or worse.  One issue that Bossobass Dave alluded to that arises in ported systems is the tendency for the port to overload, causing chuffing and power compression around the tuning frequency.  Power compression is where a particular increase in power input don't increase the output proportionally.  This happens with any system as it reaches its limits.  The problem with many ported designs is that the may reach this limit at substantially lower output for the frequencies near the tuning frequency than for the rest of the sub's range.  If you go to the "Extended Charts" section and look at the "Long Term Output Compression Magnitude", you will see that the Chase sub does not really have this problem.  Ideally, the plots here should hit 0 dB exactly.  What actually happens is that the plots are within 1 dB up until the last sweep at 118 dB, where power compression suddenly gets really high.  In that particular case, a limiter in the amp is kicking in to cause that compression, but most likely that's at the limit of the sub's ability anyway.

[Bossobass Dave]

The Chase and PSA are very comparable, IMO. Otherwise, I would not have used it in my post. The drivers are essentially the same, from the same manufacturer and I have little doubt it would be evident in the test results if PSA ever submits a sub to be tested GP.

 

My bad reading the 0 vs 0C. That obviously means a shitty driver version and, after looking at the results, I would not purchase it for any reason if the limit is a single driver, single subwoofer product.

 

As far as the comparisons go, the max burst results are THD-limited. Does THD matter? With certain music source, probably. With HT, most definitely not unless there was a reference for comparison, which no one has available in his HT.

 

Bottom line is that I would say the same thing about the PSA as I just did about the 0C version which is, basically; save your $$ until you can buy a good product. The 18.0 is a very good sub for a single sub/single driver target. The c and the PSA are not.

[maxmercy]

With only one sub, have you thought about a folded horn?  Lots of output in case you have to EQ significant peaks down.  If size is a problem, then a folded horn will not work for you.

 

JSS

[Brewjitsu]

The Chase and PSA are very comparable, IMO. Otherwise, I would not have used it in my post. The drivers are essentially the same, from the same manufacturer and I have little doubt it would be evident in the test results if PSA ever submits a sub to be tested GP.

 

My bad reading the 0 vs 0C. That obviously means a shitty driver version and, after looking at the results, I would not purchase it for any reason if the limit is a single driver, single subwoofer product.

 

As far as the comparisons go, the max burst results are THD-limited. Does THD matter? With certain music source, probably. With HT, most definitely not unless there was a reference for comparison, which no one has available in his HT.

 

Bottom line is that I would say the same thing about the PSA as I just did about the 0C version which is, basically; save your $$ until you can buy a good product. The 18.0 is a very good sub for a single sub/single driver target. The c and the PSA are not.

The funk audio 18.0c now uses the same driver as the 18.0 tested on here and now uses a 1000w amp. Nathan from funk says the 18.0c will have perform equally with the 18.0 but 2 db less across the graph.

[Brewjitsu]

 

Bottom line is that I would say the same thing about the PSA as I just did about the 0C version which is, basically; save your $$ until you can buy a good product. The 18.0 is a very good sub for a single sub/single driver target. The c and the PSA are not.

 

Hi bossobass dave, very interested to hear your thoughts on what products you deem as good that can be used with 240v and has a smaller footprint.