I DON'T MEAN to stir up marital strife, but one half of the husband-and-wife songwriting team of Nick Ashford & Valerie Simpson is not carrying his share of the load. Simpson's melodies always boast a fresh little hook and old-fashioned soulfulness, even when wearing a new coat of synthesizers. Ashford's lyrics, by contrast, are usually nothing more than one catch-phrase in the chorus and a lot of padding in the verses.

Moreover, when it comes to singing, Simpson's lustrous, wide-ranged soprano far outshines Ashford's thin, narrow tenor. This has been true since they were Motown housewriters in the late '60s and a fledgling duo in the early '70s. It's certainly true on their new album, "Solid."

Simpson, a fine gospel pianist, has taken to synthesizers with a vengeance. She, Joseph Jaubert, Ed Walsh and James Newton Howard play the synths that expand and brighten both her attractive melodies and her dance-floor rhythms. The two compelling up-tempo numbers from the film "Body Rock" are especially sharpened by the synth arrangements.

Unfortunately, these intoxicating confections are burdened with lyrics that offer such original insights as "Our love is solid as a rock," "Tell her: honey, I love you" or "Everybody's got to pay their dues in the jungle." And these one-liners are then hammered in with numbing repetition. A gorgeous love song such as "Cherish Forevermore" should be sung in Spanish so one could at least imagine the lyrics were as heartfelt as Simpson's soaring voice and Michael Brecker's sax solo.

ASHFORD & SIMPSON -- "Solid" (Capitol ST-12366); appearing with the O'Jays at Constitution Hall on Friday and Saturday at 8 and 11:30.