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Discussion Starter · #1 ·
Hello folks,

Dealing with an odd one here, and something that is throwing my system a bit out of balance between stereo music and surround.

I recently picked up some Wharfedale Sapphire SP-89 3-way tower speakers. Very nice looking units, with clean tweeters, and neutral and clear mids. However, there appears to be an issue somewhere in the bass section of the speakers - and both are responding the same.

These towers have a reputation for good bass, and in a testing curve I looked at online, it looks like bass should be useable down to 30hz, with roll off happening at lower frequencies. With a deep cabinets, dual ports, and twin 6.5" drivers, I don't expect CV 12" bass, but I do expect more than I'm getting. The speakers are also reasonably efficient at 91db 1W/1M, and although assembled in China, the drivers are British made Wharfedale 1751, though oddly in each tower one has a polypro dustcap while one has a fabric one. Neither looks tampered with.

The power is from a NAD T748, and when listening to the speakers in 2 channel stereo mode I'd be surprised if there is any useable bass under 100hz. There is power going to the woofers, and you can feel them moving, but there is nothing close to the type of excursion they should have. This is with fronts set to "Large" and sub "Off". There is also very little noise and or airflow via either bass port. There are also no "bad" noises such as static or coil rub....woofers seem OK.

For an experiment, I hooked up an EQ between my Yamaha CD (using analog outs) and pumped up the bass on it, and only by boosting the signal in this way did I get useable bass out of the towers. Not earth-shattering, but at least polite and present. However, when I then turned the sub on, I thought the 12" CV sub would eat a hole in the floor, or simply explode.

So I also reassigned the rear channels on the NAD to bi-amp the fronts. No change, as I could not (as I hoped) use the back amp to drive the treble section of the speakers at a different level than the bass section.

Also tried using the tone controls in the system, and with Bass at +10, treble at 0, still insufficient bass. It was basically +10db on the EQ, +10db in the amp tone control to get the bass useable via analog inputs. And last of all, I pulled a woofer in each tower, and did a visual of the crossover, each of which looked fine. And again, each speaker is responding identically to the signal from the NAD.

Guess my thoughts are now trending in a few different directions:

- Anyone else experience the same issue with Sapphires or other Wharfedale speakers?

- Is this in any way related using analog connections? Anyone else lose bass response via analog?

- Should I move to an optical in CD player to see if it processes the sound differently via the NAD's DAC?

- Do I now need to look at an outboard power amp and use the front pre-outs for the bass section to be able to get the bass section this extra signal it seems to need? Was thinking of trying this out with a NAD 7125 I have in a basement music system, and process the signal with extra bass to drive the amp section. Gah.

Posted in speakers as I'm suspicious it is a speaker issue (the bass section seems inefficient vs. the treble section), but may be an amplifier issue.
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