• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Placing speakers on top of subwoofers

DonH56

Technical Expert
Technical Expert
Patreon Donor
Joined
Mar 15, 2016
Messages
3,310
Likes
4,244
Location
Monument, CO
#81
FWIWFM I have a number of Rythmik subs in the house. I like 'em and Brian (Ding) and I have similar day jobs so I am biased. No F8 or FM8, however, and I think they are going to be dropping those IIRC (haven't spoken to Brian in a while). The FM8 is designed as a midbass driver with higher crossover and broader feedback bandwidth (all Rythmik subs are servo controlled, one reason I gravitated to them, since my first sub was a DIY servo based on similar principles ages ago).
 

Sal1950

Major Contributor
The Chicago Crusher
Patreon Donor
Joined
Mar 1, 2016
Messages
6,086
Likes
3,873
Location
Central Fl
#83
Quick OT question, trying to help a long distance friend with a base sub setup.
He has Revel F208s and will be mating to a Rhythmic E15. He has a Parasound Halo P5 that has built in crossover with adjustable low and high pass filters. Where do you think a good starting point would be for the X-over freq?
Revel Low Frequency Extension [email protected], [email protected] Hz, [email protected]
TIA
 

DonH56

Technical Expert
Technical Expert
Patreon Donor
Joined
Mar 15, 2016
Messages
3,310
Likes
4,244
Location
Monument, CO
#84
Quick OT question, trying to help a long distance friend with a base sub setup.
He has Revel F208s and will be mating to a Rhythmic E15. He has a Parasound Halo P5 that has built in crossover with adjustable low and high pass filters. Where do you think a good starting point would be for the X-over freq?
Revel Low Frequency Extension [email protected], [email protected] Hz, [email protected]
TIA

The Dolby/THX default is 80 Hz as that's where most folk cannot localize the bass. Given that crossovers are not brick-wall filters that instantaneously cut off I prefer to set the crossover an octave away from the speaker's -3 dB point. That would be 62 Hz. Floyd and Kevin at Revel both state to use 80 Hz as well so I would start there and go no lower than 60 Hz. Depending upon the room and placement a little higher or lower may provide better response.

FWIWFM - Don
 

andreasmaaan

Major Contributor
Joined
Jun 19, 2018
Messages
3,517
Likes
2,789
#85
FWIWFM I have a number of Rythmik subs in the house. I like 'em and Brian (Ding) and I have similar day jobs so I am biased. No F8 or FM8, however, and I think they are going to be dropping those IIRC (haven't spoken to Brian in a while). The FM8 is designed as a midbass driver with higher crossover and broader feedback bandwidth (all Rythmik subs are servo controlled, one reason I gravitated to them, since my first sub was a DIY servo based on similar principles ages ago).
Your original idea @stunta of a crossover point closer to 250Hz is looking increasingly attractive :)
 

Sal1950

Major Contributor
The Chicago Crusher
Patreon Donor
Joined
Mar 1, 2016
Messages
6,086
Likes
3,873
Location
Central Fl
#86
The Dolby/THX default is 80 Hz as that's where most folk cannot localize the bass. Given that crossovers are not brick-wall filters that instantaneously cut off I prefer to set the crossover an octave away from the speaker's -3 dB point. That would be 62 Hz. Floyd and Kevin at Revel both state to use 80 Hz as well so I would start there and go no lower than 60 Hz. Depending upon the room and placement a little higher or lower may provide better response.

FWIWFM - Don
Thanks Don!
 

stunta

Addicted to Fun and Learning
Joined
Jan 1, 2018
Messages
619
Likes
398
Location
Boston, MA
#87
Two FM8s should be arriving this Friday. Usually when I dial in a subwoofer, I adjust the volume by ear. Now with the FM8s, I will likely use them for 50Hz-250Hz and fill in the bottom end with my REL. Is there a more reliable way to get the volumes on everything dialed in than just using my ears?

I just realized one advantage of a single-cabinet large loudspeaker is that one doesn't have to worry about level matching.
 

Purité Audio

Major Contributor
Industry Insider
Barrowmaster
Joined
Feb 29, 2016
Messages
3,347
Likes
1,205
Location
London
#90
Sorry yes REW software is where you would start, measure your speakers in their current positions, fix any issues and go from there.
Keith
 

andreasmaaan

Major Contributor
Joined
Jun 19, 2018
Messages
3,517
Likes
2,789
#91
Sure but I wanted to know if there is a well-established process. Given the room's response is not flat, how do I calibrate if I am playing a frequency sweep tone?
There are a number of ways to do this, but let me suggest one thorough and reliable method:
  1. Firstly, read up on how to measure speakers if you haven't done it before (this article is not a bad start, and this article is about REW specifically).
  2. Set the levels so that the speakers are at a moderate/typical level at the listening position (or take a gated far-field measurement so that the speakers are at an arbitrary/standard level of say 84dB or 90dB at 1 metre).
  3. Next, take a ground-plane measurement of your ATCs at the reference level with no filters in place. Note down the distance from mic to speaker, and also note the SPL across the region in which the crossover will likely be (around 150-250 Hz, where the speakers should measure fairly flat).
  4. Use your preamp to set a high-pass filter (HPF) around where you want to cross over to the subs, say 200Hz to begin with.
  5. Take another ground-plane measurement of the ATCs to ensure they are crossing over at the intended point and with the intended slope. For example, if the preamp uses 4th order Linkwitz-Riley filters, setting a 200Hz HPF should mean that the speakers are -6dB at 200Hz (relative to the level at 300Hz+), and about -24d at 100Hz.
  6. Take the FM8s outside for a ground-plane measurement (without any filters dialled in) at the same fixed distance and adjust the level until it hits your chosen reference level around the middle of its intended operating range (say 100Hz).
  7. Set a low-pass filter (LPF) at 200Hz for the FM8s, using the same slope as you did for the ATCs (e.g. LR4).
  8. Take another ground-plane measurement to ensure that they are also -6dB at the crossover point relative to the reference level and -24dB at 400Hz.
  9. Now stack the ATC and the FM8 as you ultimately will when they're set up, and take another ground plane measurement, but with both the speaker and woofer on their sides (so that both are touching the ground). If you're lucky, the crossover will work correctly and you'll end up with a flat response through the whole bass and low midrange. You've now correctly crossed over the ATCs to the FM8s.
  10. If you're not so lucky, there will be a dip or perhaps peaks at some point around the crossover. If that's the case, post the measurements here and we'll go from there :)
If all that is too much work, there are much simpler albeit less reliable ways to do it in-room.
 

Soniclife

Major Contributor
Patreon Donor
Joined
Apr 13, 2017
Messages
1,986
Likes
1,600
Location
UK
#93
Two FM8s should be arriving this Friday. Usually when I dial in a subwoofer, I adjust the volume by ear. Now with the FM8s, I will likely use them for 50Hz-250Hz and fill in the bottom end with my REL. Is there a more reliable way to get the volumes on everything dialed in than just using my ears?.
I would find a way to ensure you have confidence in the crossover slopes being what you expect, and then play with the levels by ear for a while, nothing wrong with playing with it by ear for a bit. Make notes.

Don't assume your Rel is better at the bottom end than your new ones, it might be better used to help over the very low frequencies, and do the distributed bass thing.

I just realized one advantage of a single-cabinet large loudspeaker is that one doesn't have to worry about level matching.
And one of the disadvantages of most if that they cannot be dialed in other than by moving them about, you have way more control.

Have you read this thread...
https://www.audiosciencereview.com/...m2-audiolense-digital-crossovers-w-subs.2369/
 

Sal1950

Major Contributor
The Chicago Crusher
Patreon Donor
Joined
Mar 1, 2016
Messages
6,086
Likes
3,873
Location
Central Fl
#94
The reason I am such a big fan of completely full range loudspeakers!
Keith
They have their limitations when compared to using multiple subs-locations.
 

Purité Audio

Major Contributor
Industry Insider
Barrowmaster
Joined
Feb 29, 2016
Messages
3,347
Likes
1,205
Location
London
#95
No. You can still use other subs destructively, to have full range loudspeakers like the 8Cs already puts you ahead of the game .
Keith
 

Sal1950

Major Contributor
The Chicago Crusher
Patreon Donor
Joined
Mar 1, 2016
Messages
6,086
Likes
3,873
Location
Central Fl
#97
No. You can still use other subs destructively, to have full range loudspeakers like the 8Cs already puts you ahead of the game .
Keith
We were discussing sub-woofers remember.
See the title of the thread.
I wouldn't call 8C's a deep bass speaker in any case.
 

Purité Audio

Major Contributor
Industry Insider
Barrowmaster
Joined
Feb 29, 2016
Messages
3,347
Likes
1,205
Location
London
#98
They have to go below the threshold of audability for you to call them a ‘deep bass’ speaker don’t be silly.
Keith
 

Sal1950

Major Contributor
The Chicago Crusher
Patreon Donor
Joined
Mar 1, 2016
Messages
6,086
Likes
3,873
Location
Central Fl
#99
They have to go below the threshold of audability for you to call them a ‘deep bass’ speaker don’t be silly.
Keith
Yea OK, your right. NOT
Quit whoring your products and sales in every thread, that's what DESPERATE DEALER is for.
(edit) typo corrected so Keith can find his way home)
 
Last edited:
Top Bottom