Hi there, sorry for the delay in responding. I have never owned the Spendor SP1, but do have BC1, BC2 and Rogers LS3/6. Your system should not sound constricted. I would not think thst the speakers are causing this, unless faulty. The most likely suspect in my view would be the pickup cartridge, perhaps try another. Your recordings, if from the 50's may not be of that good a quality anyway. Try some different sources as inputs, CD, Radio even PC. I hope this is of some help.