These inevitable questions came up on AVS. I'll consolidate this and more info the announcement thread and a thread about upgrades.
I guess I will be the first to ask. I have the SubM HP+ model Master/Slave and use a receiver with Audyssey XT32 and an SMS-1 (using REW to set the filters) for DSP. Given that - should I consider upgrading my amp?
And how much will this upgrade cost? Any trade in program for the HPi+ amp?
Upgrades will work out to a net cost of $900 with return of the original 1kW amplifiers, $500 with return of an HP amplifier (2400W), and $400 with return of an HP+.
Of course upgrading from a 2400W HP amplifier allows the addition of a slave unit. This certainly offers some savings over another powered unit, but between the upgrade cost, the slave cable and the price of the new units, the savings over a new HP+ are not as big as those who already have a plus unit at about $500 with multiple SubMersive discounts applied.
I'll be doing some more listening and comparison, but going from original HP+ to new HP+ will be a very modest upgrade. The biggest benefit of the new amp are the new features. I polished the performance a bit further around max output in the process. The perceived value of those features will vary greatly from one owner to the next. Let's run through a couple of the features:
1. [U]12V trigger and auto sensing[/B]: There are 12V trigger power devices available for ~$100. Those switch to 100% off, where the on-board 12V trigger gets to 1/4-1/3rd of idle power and eliminates any chance of induced noise while the system is off.
2. [I]LF EQ (low shelf/adjust extension/room size fitting)[/B]: If you have flexible manual EQ in the system in theory you can implement most of what the program settings and LF EQ offers, but many don't or won't get quite the right shape of things where this makes it very easy to dial in whatever lift/house curve you are after.
3. [U]Delay adjustment 0-20ms[/B]: If you have a single powered unit being used with a modern surround processor, the delay adjustment isn't of much advantage. For those with more than one powered subwoofer, the delay function could allow someone to eliminate a device and A/D-D/A step in an external box like a MiniDSP or DSP-30, particularly if you already have a room correction system like Audyssey XT32 or Dirac. For Dirac this is a significant advantage when using multiple powered units as it is much better equipped to correct the response of the subwoofers as a group after you first adjust placement and delay to get a good summation and starting point. Even though Audyssey XT32 does attempt to apply delay, it still EQ's the subs as a whole, and I have always found better results if the delay and blending is done manually and then let Audyssey correct the whole.
4. [U]Low pass crossover 30-120Hz + 200Hz[/B]: The new amplifier adds a 4th order (24dB/octave) low pass filter. While I very much prefer for 2ch listeners to have some form of response correction in the system to get the best sound quality, this opens many more possibilities in 2ch systems where you can use devices such as DSPeaker's AntiMode products or MiniDSP's Dirac boxes which don't include a low pass. You can also use the internal low pass to get a workable blend with the speakers and then use a single, full-range correction system such as Dirac, Trinnov, or AntiMode Dual-Core. Having a low pass at the amplifier can sometimes makes for a useful added flexibility in a home theater setup when blending multiple units or taming some in-room peaks just above the operating range. If the delay adjustment didn't quite get rid of some localization of a rear subwoofer, or you're having trouble getting a good blend with only delay adjustment, sometimes a low pass can work on its own or in combo with less overall delay as the low pass filter has some inherent delay of its own that changes with frequency to give a little different blend and less upper frequency contribution.
5. [U]XLR & RCA inputs[/B]: No need for adapters. While those who know they will eventually have a preamp with XLR connections might still want to run an XLR cable and use adapters, the best practice will be connecting XLR-XLR & RCA-RCA. This gives the lowest probability of hum or buzz. These higher power models do need to still use the 3rd pin safety ground, but addressing ground loop issues in an XLR-XLR system is typically a much simpler matter of just grounding the preamp.