Polk 7b- Where's the bass?????????????? Polk speaker experts?

[highfigh]

One of my customers clearly needs more/better amplification but while I'm checking out his Polk 7b with the crunchy woofer voice coil, I was struck by the glaring lack of low end. I turned on the Loudness control and it was a bit better, but the odd thing is that the bass sounds best when I stand at the side, so I reversed the leads to the woofer and it immediately improved. The 'Acoustic Compensation' control on the receiver I was using has bass boost, Presence and Loudness- this speaker doesn't need any more highs and with the 10" passive radiator, I would have thought it would do better on the low end but Holy Hand grenades!

I have a pair of 8 Ohm Peerless woofers from a previous build and they were better, even though the Polk woofers are 4 Ohm.

The original woofer is the 6502, which has been discontinued and I found a driver at Speaker Exchange that they sell as a replacement, but the sensitivity is 2dB lower.

The deep bass is decent, but the midbass is terrible. I may fill the cabinet and play with it a bit, to see if I can help it.

I don't remember their speakers sounding this way, but I haven't listened to this model. I switched to my old Jamo J101 and they were far better without a passive radiator.

This customer needs speakers that are much more capable than the ones he has and he needs more/better power.

Is anyone familiar with this model and have you done any mods to help them?

 

[jinjuku]

They look like typical monkey coffin 3 way junk to be honest.

 

[highfigh]

They look like typical monkey coffin 3 way junk to be honest.

Two way- they have a 10" passive radiator.

In my search for info, I found a link that has the full Polk lineup from 1986 (the date shown on the back of the woofer) and these listed at $249.95 which is similar to $700, now. Amazing, how much better someone can do by building their own for $300, now. These could have been improved by Polk using an 8" and passive, rather than a 6-1/2"

He also has a pair of Advent speakers from roughly the same time. Not sure why he didn't just buy two pairs of the Advents, but....

 

[MrBoat]

Two way- they have a 10" passive radiator.

In my search for info, I found a link that has the full Polk lineup from 1986 (the date shown on the back of the woofer) and these listed at $249.95 which is similar to $700, now. Amazing, how much better someone can do by building their own for $300, now. These could have been improved by Polk using an 8" and passive, rather than a 6-1/2"

He also has a pair of Advent speakers from roughly the same time. Not sure why he didn't just buy two pairs of the Advents, but....

A 6.5" woofer? That's like my personal minimum for hopes of any bass that I can feel at all, anyway. Old speakers like that with limited displacement tend spend a life being pushed to, and beyond their upper limits. If they meant that much to me and had age on them, I'd rebuild the crossovers whether they needed it or not.

Advent speakers, were what ended up decisively turning me towards JBL and 3-way designs instead. I'm still on the fence with regard to 2-way speakers for full range duty.

 

[highfigh]

A 6.5" woofer? That's like my personal minimum for hopes of any bass that I can feel at all, anyway. Old speakers like that with limited displacement tend spend a life being pushed to, and beyond their upper limits. If they meant that much to me and had age on them, I'd rebuild the crossovers whether they needed it or not.

Advent speakers, were what ended up decisively turning me towards JBL and 3-way designs instead. I'm still on the fence with regard to 2-way speakers for full range duty.

I built my speakers in a 2.5 way with dual Peerless 6.5" and the low end is really smooth and goes pretty low but the real benefit is the mid-bass through the midrange- voices in the dialog in all sources sound incredibly natural and once time when the radio was on, they interviewed someone I know and at one point, he said "Jim, what are you doing?"- seriously, it was like the guy was in the room and I actually answered with "What? I didn't do anything!". That was weird. He laughed hard when I told him about it.

I removed the crossover yesterday- it's mounted to the terminal cup and as soon as it came out, the bass improved. I plan to measure the caps to see if they're out of spec (I'm betting they are). I found a crossover diagram and will check the speaker against that.

I listened to some tracks with the huge pipe organ in Atlantic City- when the lowest rank was playing, the midrange was terribly modulated and that reinforced my opinion that if the system will be playing extremely low frequencies, it either needs a truly full-range large woofer or a subwoofer. Period.

It also made me miss the EV 30 woofers I had to sell because I couldn't get the cabinets into my house and wouldn't have a room where I could use them.

 

[davidscott]

I had a pair of Polk 7bs back in the 80s. Not a lot of bass but a really nice mids and treble. Problem was they couldn't handle any power and I ended up blowing 3 tweeters. And I was running them with a Kenwood basic amp with 105 WPC so I don't think they were clipping. Kudos to Polk for repairing them each time but I finally sold them and got some DCM Time Windows. Never had a problem with any blown drivers with them.