Weak Bass from my SP 1/2s

Bojack 05-06-12
... They just have very low bass output under anything below about 70 Hz (to my ears) though they are rated for +/- 3db at 45Hz. Interestingly enough, my old SP 2/3s, which were smaller and rated down to 60Hz, clearly had significantly more extension connected to the same front end. I have moved them around to no avail.

What is the distance between the listening position and the rear wall? And have you tried changing that distance, in addition to changing the position of the speakers?

While the amplifier figures to be part of the problem, if the distance between the listening position and the rear wall is in the vicinity of roughly 5 or 6 feet, reflections from that wall can result in a large amount of attenuation of frequencies in the vicinity of 50 or 60 Hz or thereabouts. Perhaps that wasn't as noticeable with the smaller speakers because their different radiation pattern may have resulted in sidewall reflections that could have partially negated or compensated for that attenuation.

Divide the distance between the listening position and the rear wall, measured in feet, into 281.5 to derive the center frequency of that cancellation effect, based on the speed of sound in dry air at 68 degrees F at sea level, which is 1126 feet/second (281.5 = 1126/4). As a rough approximation I believe that significant attenuation may occur over something like a 2/3 octave range centered about that frequency.

Regards,
-- Al

Take it from me, sometimes speaker-amp matching can be mystifying. The load the amp detects from the speakers does not logically work as expected; does not always translate to the sound (bass or otherwise) that the specifications would indicate should occur. It can be hit and miss.

Wow, thanks for all the responses. I think I might demo an amp with significantly more current and power than my NAD and see what happens. Something tells me though, that there is a disconnect between the size of the 1/2s and what they are capable of. And as funds allow, I might look at an REL B3 as well.

I like the bass from my NAD 326BEE with Sound Dynamic speakers it is full and controlled and seems to go quite low

fwiw...

I also use RELs but the Spendors can have good bass. Back in the early 80s I use to use SP 2s to demo Krell amps when I was a Krell dealer. But I had a live end/ dead end listening room with a concrete floor.

You need more power as already suggested. I might try something with much much more juice like a Wyed4Sound amp, as big as you can afford, It is class D o it won't be as rich as some other amps (class A or A/B) but the price per watt ratio goes up dramatically.
And before someone gets on their high horse and tells me that it's the quality of the power not the amount I am well aware of that. In this case I am not suggesting junk and would say get a Pass XA150 but I don't think the OP can afford it. Maybe I am wrong and yes if the first watt sucks what goo is 300 more of them.

i had the sp 2/3s, which i drove with as much as 150w of good ss power. i could never coax sufficient bass out of 'em either and always felt a sub was essential.

It could also just be the way the speakers interface with the room. I've had experiences where smaller speakers with supposedly less bass response produced a bigger and fuller bass in my room than larger speakers. It just works that way sometimes.

In my opinion, you are way underpowered with the NAD 25 watt unit. I run my Spendor SP1/2E speakers with a McIntosh MC352 stereo amplifier, and I supplement the bass with a REL Stentor II subwoofer. Before getting the REL, I was not happy with the bass response. But I'm happy now. Even with pretty good amplification, the Spendors just don't have enough deep bass to go full range, and so they benefit a lot from a decent subwoofer. So beefy amp, yes, although I've heard others talk about lower-powered tube amps with these speakers. No experience there, so I can't say whether this is true. But I can confirm that having a subwoofer in a Spendor system is the way to go.

I have the same speakers but do not have this problem. Right now I am using a 400 watt amp on mine [CJ 350]. This is overkill; my other speakers need it. I suspect your amp is the problem. I have driven SP 1s with a lot of amps and never had bass problems; smallest was probably a MF A1 25 watt class a. I would get a better amp; the speakers will sound better.