MartinLogan Revamped Grotto Line Digs Deep with 1kW 12" & 15" Subwoofers

[shadyJ]

​

MartinLogan has impressed us with their subwoofers in our recent reviews of the Dynamo 12 and Abyss 10. The new refresh of the Dynamo and Abyss series was greatly improved over their predecessor subwoofer lines. Now, MartinLogan looks to be giving the same treatment to their Grotto series, which last used that name in 2007 with the Grotto i. However, MartinLogan is taking the Grotto name way past the caliber of subwoofers that the older Grotto subs were. The older Grotto subs were sealed 10” models with 250 to 300 watt amplifiers. The new Grotto subs have a 12” driver and a 15” driver, with both drivers loading dual passive radiators. What is more is that these new models are powered by a 1,000-watt RMS amplifier. Those are some monster specs that make the older Grotto subs seem quaint by comparison. Read our preview to learn more about MartinLogan's new Grotto subwoofer series!

READ: MartinLogan Grotto 12 and Grotto 15 Subwoofer Preview

 

[GIEGAR]

On the other hand, passive radiators do have their own compromises, such as the weight of the radiators being much heavier than the weight of the air within a port, and thus their reaction time will not be as quick.

I that right? My understanding is the mechanical mass of the PR's diaphragm (Mms) is the same as the mass of the slug of air in the tube of an equivalent ported system.

AE Speakers --- Superb Quality, Unforgettable Performance, Definitely.

 

[TLS Guy]

View attachment 76506​

MartinLogan has impressed us with their subwoofers in our recent reviews of the Dynamo 12 and Abyss 10. The new refresh of the Dynamo and Abyss series was greatly improved over their predecessor subwoofer lines. Now, MartinLogan looks to be giving the same treatment to their Grotto series, which last used that name in 2007 with the Grotto i. However, MartinLogan is taking the Grotto name way past the caliber of subwoofers that the older Grotto subs were. The older Grotto subs were sealed 10” models with 250 to 300 watt amplifiers. The new Grotto subs have a 12” driver and a 15” driver, with both drivers loading dual passive radiators. What is more is that these new models are powered by a 1,000-watt RMS amplifier. Those are some monster specs that make the older Grotto subs seem quaint by comparison. Read our preview to learn more about MartinLogan's new Grotto subwoofer series!

READ: MartinLogan Grotto 12 and Grotto 15 Subwoofer Preview

ABR tuned enxlosues roll of at 36 db. per octave below f3 as opposed to 24 db. per octave for ported enclosures, so there is significantly less bass extension below f3.

 

[kini]

ABR tuned enxlosues roll of at 36 db. per octave below f3 as opposed to 24 db. per octave for ported enclosures, so there is significantly less bass extension below f3.

But zero chance of port noise. And these aren't meant to be ULF monsters. Still don't see how these going to be much better than their other subs.

 

[shadyJ]

But zero chance of port noise. And these aren't meant to be ULF monsters. Still don't see how these going to be much better than their other subs.

In terms of raw performance, I don't think they will exceed the usual slate of high-value brands that are so often mentioned, but the feature set, appearance, and build quality are certainly going to be really good. Probably like the Abyss sub that I reviewed recently, except scaled up to 12" and 15" drivers. They should be good performers, although maybe not SPL/$ top dogs.

 

[oniiz86]

ABR tuned enxlosues roll of at 36 db. per octave below f3 as opposed to 24 db. per octave for ported enclosures, so there is significantly less bass extension below f3.

@TLS Guy Please excuse my ignorance but is there any way this steep 36dB rolloff can be improved? So in reality there actually are no benefits to PR designs despite the marketing nonsense saying otherwise, they do not really offer the benefits of both ported & sealed designs whilst minimising their shortcomings, I heard the reasoning why Definitive Technology when they released their Demand loudspeaker series several years ago continue to use PRs because of their consistency compared to ports but that makes zero sense, what is so inconsistent about ports & they are naturally the more cost-effective solution, well I guess the low tier manufacturers like Definitive Technology would utilise really cheap & nasty Polypropylene PR drivers at least MartinLogan wouldn't dare skimp on the quality of their PRs which are the same Aluminum material as their active driver.

 

[shadyJ]

@TLS Guy Please excuse my ignorance but is there any way this steep 36dB rolloff can be improved? So in reality there actually are no benefits to PR designs despite the marketing nonsense saying otherwise, they do not really offer the benefits of both ported & sealed designs whilst minimising their shortcomings, I heard the reasoning why Definitive Technology when they released their Demand loudspeaker series several years ago continue to use PRs because of their consistency compared to ports but that makes zero sense, what is so inconsistent about ports & they are naturally the more cost-effective solution, well I guess the low tier manufacturers like Definitive Technology would utilise really cheap & nasty Polypropylene PR drivers at least MartinLogan wouldn't dare skimp on the quality of their PRs which are the same Aluminum material as their active driver.

The roll-off is an inescapable consequence of the design. You could shape the natural response with equalization, but you can't make it perform past its physical limits. Polypropylene isn't going to perform differently from aluminum at low frequencies. The reason why these manufacturers use PRs instead of ports is that they allow the enclosures to be smaller, and they avoid some of the problems that ports have such as turbulence and unwanted port resonances. Passive radiators have their own disadvantages, but these manufacturers have decided that the trade-offs are worth it.

 

[oniiz86]

The roll-off is an inescapable consequence of the design. You could shape the natural response with equalization, but you can't make it perform past its physical limits. Polypropylene isn't going to perform differently from aluminum at low frequencies. The reason why these manufacturers use PRs instead of ports is that they allow the enclosures to be smaller, and they avoid some of the problems that ports have such as turbulence and unwanted port resonances. Passive radiators have their own disadvantages, but these manufacturers have decided that the trade-offs are worth it.

@shadyJ I understand that is primarily the sole reason why manufacturers use PRs to save space but in the case of the Definitive Technology Descend DN15, it has such a large enclosure, it completely dominates the room, well one thing Definitive Technology have certainly managed, they've made the largest enclosure with the quietest SPL output of any 15" subwoofer ever released probably, that is no mean feat The Grotto 15 will certainly eat the DN15 for breakfast & then some despite it's smaller enclosure but of course it has a healthy 1000W RMS amplifier with a beefier driver & motor structure design.