With the nc252mp do I need to run a subwoofer to prevent issues or will it be fine powering those towers and center without the sub? And yea, have way too many electronics running and do like to cut down power where possible.
A subwoofer can help in most cases by offloading both the amp and the main speakers. Reducing the load on the amp reduces its power requirements and distortion, ditto the speakers which usually perform better when not required to handle deep bass (N.B. I did not read back to see what speakers you have, sorry). Take a look at "equal loudness" curves and note how going from say 1 kHz to 100 Hz the 100 Hz sound needs to be 10 to 20 dB louder (SPL) than the 1 kHz (midrange) sound just for the bass tone to sound as loud. That is 10 to 100 times the power, a significant difference, and it gets worse as you go lower. Using a subwoofer means the main amplifier and speakers may require 10 to 1000 times less power to cover the bass than without a sub, with correspondingly lower distortion.
But nothing stops you from getting the amp and trying as-is first! You can always add a sub later. The issue often is that you do not know you need one until you have one and realize how much better the system can sound.
As an aside, to stay at least marginally on topic, my Buckeye nc252mp is powering my overhead Atmos speakers and has done so for several years with no noise, great sound, and is perfectly adequate for the job. I do use more powerful amps on my main speakers, but they are much less sensitive (requiring more power to achieve the same SPL) and further away plus carry the main movie and music content so generally play louder than the overheads. Furthermore, Dylan (Buckeye) is very easy to work with and supports his customers to the hilt.
My ancient "why subs?" post:
I use subs, and have for decades, for all the usual reasons:
- Very (perhaps extremely) few "large" speakers actually play well below 40 Hz let alone 20 Hz. They distort heavily when presented with large bass signals (which most are -- see Fletcher-Munson) and driving them hard down low robs headroom for higher frequencies and causes distortion well above the fundamental signal frequency (harmonic and nasty intermodulation). Subs typically enable the mains to operate with much lower distortion.
- Very rare is the room setup such that the best place for stereo imaging and soundfield is the best place for the subs (or deep bass drivers) to counter room modes and such. Having independent subs provides placement options to smooth the in-room response. It is almost impossible to counter a null without subs (typically must move the MLP or change the room's dimensions though there are purpose-built panels that can also work). This is one of the things that led me to subs despite having quite capable mains.
- Powered subs offload the main amplifiers of the need to provide deep bass energy, providing more headroom and cleaner sound from the amplifiers.
- Music (let alone action movies) often contains deep bass content even if it is not real obvious. Kick drums, tympani, organ, sure, but also piano hammer strikes, plucked strings, beat patterns from instruments playing together, etc. May not really notice when they are there but usually obvious when they are taken away. Having subs fill in the bottom octave or three can make a difference.
- Purpose-built subs can provide high output cleanly at relatively low cost. The amplifiers and drivers need only cover a fairly limited frequency range so have fewer constraints upon them than woofers in a full-range system.
I do prefer main speakers with fairly deep bass and always have. Crossovers are not brick walls so a fair amount of energy still comes from the mains an octave below the crossover frequency. Higher-order crossovers allow you to reduce the overlap, but I still like having the capability. I have never really understood the idea of running "passive" bi-amping as implemented by an AVR (sending full-range signals to multiple channels and letting the speaker's crossovers separate frequency bands -- wastes amplifier headroom and seems to me of little benefit). Nor do I agree with the "plus" setting putting subs and mains in parallel; again, my idea has always been to isolate the two for the reasons above.
My first sub was a DIY design using an Infinity IRS woofer with my own control box to provide the crossover and a servo circuit using the second voice coil of the woofer. I had a Hafler DH-220 around so also incorporated a circuit to bridge it for use as a subwoofer amp. It worked well and the -3 dB point was ~16 Hz. I now run four small (F12) Rythmik subs using a similar (but updated) servo design with my Revel Salon2's and am happy with the result.
FWIWFM/IME/IMO/my 0.000001 cent (microcent) - Don
www.buckeyeamp.com
