Bass response help needed.

[MisterCoffee]

Hello folks,

I have a pair of Delphi Imager speakers on their included stands in a 16' x 18' room with 9' ceilings. Hardwood floors about 50% covered in throw rugs. The speakers' backs are about 18" from the 16' wall, about 10' apart. I included a photo I found of the same model speakers below.

When I'm in my preferred listening spot on a couch about 10' away from the wall, the tweeters are more or less pointing at my head due to the angled stands. It's a nice isosceles triangle. The bass is muddy with a lot of emphasis around 150-200Hz when I play, for example, UFO's Phenomenon album on CD. The kick has no weight. But when I stand up, the bass improves dramatically -- the kick at around 50Hz is well-defined and occupies its own space. 100-200Hz is no longer muddy, it's detailed.

I've tried moving the speakers further from the walls, closer to the walls, removing the stands, toeing them in, etc. It's like they want to be two feet below my floor so my ears are above them instead of in their path.

Any ideas of other things to try? Cheers!

 

[GordonW]

Just a wild guess of an idea- but, have you tried turning them upside-down, and using the left speaker on the right and vice-versa?

Could be a floor-bounce issue- upside-down positioning would definitely change that. Better or worse- the only way to find out is to try it.

Also- are both of those large drivers woofers, or is one a woofer and one a passive radiator? If they're both active woofers- you might want to check to see if one or more woofer is out-of-phase (inverted polarity) compared to the other. You can do a quick check with a flashlight battery on the speaker terminals (of course, making sure the speaker is disconnected from the amp, beforehand, naturally)- briefly connecting the battery to the speaker terminals, should make all the woofers in both cabinets go the same direction on make and break. If they move in different directions- that's probably a polarity inversion on one.

Regards,
Gordon.

 

[MisterCoffee]

Just a wild guess of an idea- but, have you tried turning them upside-down, and using the left speaker on the right and vice-versa?

Could be a floor-bounce issue- upside-down positioning would definitely change that. Better or worse- the only way to find out is to try it.

Also- are both of those large drivers woofers, or is one a woofer and one a passive radiator? If they're both active woofers- you might want to check to see if one or more woofer is out-of-phase (inverted polarity) compared to the other. You can do a quick check with a flashlight battery on the speaker terminals (of course, making sure the speaker is disconnected from the amp, beforehand, naturally)- briefly connecting the battery to the speaker terminals, should make all the woofers in both cabinets go the same direction on make and break. If they move in different directions- that's probably a polarity inversion on one.

Regards,
Gordon.

I did try swapping channels and also running in mono. I did not try upside-down, but I will. Good question about the woofers -- I don't know but I'll check the phase and see what happens.

Thanks for the suggestions!

 

[twiiii]

Two many mistakes in types of drivers and the use of multiple tweeters spaced to far apart to make any useful recommendations. I bet the crossovers are not the best they could be either.

 

[loudnoises]

Symmetry looks awesome, but in a listening space it will often cause huge issues with reflections.

 

[SaSi]

150-200Hz sounds just about right for a room mode on the long axis. If you could provide the room's dimensions, we could confirm.
The fact that you, standing up, experience bass notes, proves to me that your issue is untamed room modes (resonances) due to high reflections from walls.

I had similar issues in my dedicated listening room and I could mount floor to ceiling absorption to the front wall corners, behind the loudspeakers, and that alone made a huge difference. So much that I postponed, for years, to treat the ceiling and add some diffusion to the back wall.

 

[biotech]

Perhaps try a preamp (or receiver) with Audyssey MultEQ XT32 or similar room equalization processing extending into the deeper base frequencies. This could/should reduce a good amount of room reverberation, standing waves.

Maybe tilt the speakers forward a bit so they are pointed parallel to ground, not slightly up.

 

[jazzmans]

Hello folks,

I have a pair of Delphi Imager speakers on their included stands in a 16' x 18' room with 9' ceilings. Hardwood floors about 50% covered in throw rugs. The speakers' backs are about 18" from the 16' wall, about 10' apart. I included a photo I found of the same model speakers below.

When I'm in my preferred listening spot on a couch about 10' away from the wall, the tweeters are more or less pointing at my head due to the angled stands. It's a nice isosceles triangle. The bass is muddy with a lot of emphasis around 150-200Hz when I play, for example, UFO's Phenomenon album on CD. The kick has no weight. But when I stand up, the bass improves dramatically -- the kick at around 50Hz is well-defined and occupies its own space. 100-200Hz is no longer muddy, it's detailed.

I've tried moving the speakers further from the walls, closer to the walls, removing the stands, toeing them in, etc. It's like they want to be two feet below my floor so my ears are above them instead of in their path.

Any ideas of other things to try? Cheers!

View attachment 3389223

After reading the linked thread,

1. these have no crossovers, just a cap on the tweeter, both 8" drivers run full range.
2. with the second tweeter, there's supposed to be a crossover cable between the pair, a-la polk sds.
they are a form of d'appolino array.

apparently one of the people who was with delphi owns golden ear speakers, or did in 2015.
interesting thread, interesting design.

OP, it certainly sounds like room nodes. try the long wall, diffusion behind them, etc etc.

 

[jazzmans]

Two many mistakes in types of drivers and the use of multiple tweeters spaced to far apart to make any useful recommendations. I bet the crossovers are not the best they could be either.

no offense intended, as you have a lot of experience, but you should read the linked thread before spouting off on these.


txt from that thread


and a link to their brochure

I was partners with Marco the principal designer, and yes we made turntables and amplifiers. The later model of the speaker was called the Imager, we used no crossover and had speaker cables connected from one speaker to another this concept was later adopted by Polk. Fun times.

Looking under goole patents ours was in 1980. It makes no difference now as i have long moved on and the company was a hobby anyway as my real job was with the Federal Govt.

The 70`s and 80`s were fun times in the San Fernando Valley, many of the early designers for quite a bit of audio designed worked at the Skunk Works, JPL, Boeing ect. Great times, it is so different now.

Marco Karpodines was the designer. He held many patents in speaker cabinet and driver design. Our drivers were all made at our Encino factory, every piece was made in house we employed about 30 people at our height of production which included our amp and TT. The amp and TT are still in production today by two major audio companies across the pond so i will not comment any further about those products.

All of our speakers that i have seen for sale in recent years have all had some of the drivers replaced, which is a-shame because a big part of our sound was the construction of the drivers. A set on ebay right now have had the drivers replaced.

Yes the drivers were full range and your correct about the filter. The sound was very open with a 3D image yet accurate. The Absolute Sound gave us a good write up in 82.

Those are very early speakers. To me it looks like the bottom drivers have been replaced. I no longer have any old photos or info. But man those were good sounding speakers.

It`s funny all of this talk about Polk and Delphi speakers, as i now own GoldenEar speakers lol.

 

[Mike_S]

you may also be sitting in a null point. Only way to fix that is moving the speakers around.
Usually if it's out of phase all the bass is gone, not just in only point, but everywhere. Usually if you do a simple fader from full left to full right and you get more bass at the extremes it's a phase issue. But also as said, if you have more then 1 woofer per speaker, internally they can be out of phase.

Room acoustics are the most important thing, one of the hardest to sort out. If you get the best bass, you might not have the best treble, horrible image, and soundstage. It's going to take a lot of work to find the spot with the least amount of compromises.

 

[MisterCoffee]

150-200Hz sounds just about right for a room mode on the long axis. If you could provide the room's dimensions, we could confirm.
The fact that you, standing up, experience bass notes, proves to me that your issue is untamed room modes (resonances) due to high reflections from walls.

I had similar issues in my dedicated listening room and I could mount floor to ceiling absorption to the front wall corners, behind the loudspeakers, and that alone made a huge difference. So much that I postponed, for years, to treat the ceiling and add some diffusion to the back wall.

Thanks. Dimensions are in my OP

 

[MisterCoffee]

Maybe tilt the speakers forward a bit so they are pointed parallel to ground, not slightly up

I did try that but thanks

 

[MisterCoffee]

OP, it certainly sounds like room nodes. try the long wall, diffusion behind them, etc etc

Yeah, looks like it'll be trial and error along those lines. Thanks!

 

[MisterCoffee]

you may also be sitting in a null point. Only way to fix that is moving the speakers around.
Usually if it's out of phase all the bass is gone, not just in only point, but everywhere. Usually if you do a simple fader from full left to full right and you get more bass at the extremes it's a phase issue. But also as said, if you have more then 1 woofer per speaker, internally they can be out of phase.

Room acoustics are the most important thing, one of the hardest to sort out. If you get the best bass, you might not have the best treble, horrible image, and soundstage. It's going to take a lot of work to find the spot with the least amount of compromises.

Yeah, I'll just keep experimenting. Maybe I'll try a different set of speakers to see if they are easier to position in the room. Thanks!

 

[BmWr75]

You are dealing with a bass room mode and acoustic treatment helps that problem. GIK Acoustics will give you a free estimate. That is who i used.

 

[toddalin]

Moving your seating position, even by inches, can have as great/greater impact than moving the speakers. The sound from my system is totally different if I even just lean/sit forward several inches on the couch.

Something that hasn't been suggested or maybe overlooked, maybe because it may not be so easy to do, would be to turn the speakers on their sides so the woofers are near the floor and get that reinforcement, rather than destructive bounce, keeping the tweeters up top. I'm assuming that the round area is a port, rather than a midrange.

 

[Mr Boochie]

But when I stand up, the bass improves dramatically -- the kick at around 50Hz is well-defined and occupies its own space. 100-200Hz is no longer muddy, it's detailed.

Have you tried pointing the speakers down? Maybe reverse them on the stands and see/hear what happens?

 

[MisterCoffee]

Have you tried pointing the speakers down? Maybe reverse them on the stands and see/hear what happens?

Yes, per earlier suggestions.