Reduce the booming bass

[hpolkerman]

Hello,

I've got the "Standaard" speaker package from Speaker&co from holland.

It has a Peerless CSX-217T with a fs of 28hz and a Qes of 0,29 together with an Qts of 0,27 and EBP of 96 it is well suited for Bassreflex.

Now I want to temper the bass a little bit (It's a bit to aggressive). Can I still make a Closed Box version of it, looking at the T/S parameters? Or should I put some dampening wool in the Bassreflex port?

What is the best option to take? Would the ScanSpeak flow resistance be any good in a small Closed box with the peerless?

Greetz. Henri

[AKN]

Originally posted by hpolkerman
Hello,

I've got the "Standaard" speaker package from Speaker&co from holland.

It has a Peerless CSX-217T with a fs of 28hz and a Qes of 0,29 together with an Qts of 0,27 and EBP of 96 it is well suited for Bassreflex.

Now I want to temper the bass a little bit (It's a bit to aggressive). Can I still make a Closed Box version of it, looking at the T/S parameters? Or should I put some dampening wool in the Bassreflex port?

What is the best option to take? Would the ScanSpeak flow resistance be any good in a small Closed box with the peerless?

Greetz. Henri

Hi hpolkerman,

How is your box currently aligned, fb and vb?

[BHTX]

Entered the CSX-217T into WinISD with specs from this page:
http://www.lautsprechershop.de/hifi/...eerless_en.htm

Any idea what volume it's in and what it's tuned to? I'm assuming you don't, but just thought I'd ask anyway..

WinISD does show an EBP of 96.6, and suggests a BB4/SBB4 alignment..

BB4/SBB4:
25 liters @ 28 Hz
-3 dB at 60 Hz
-6 dB at 41 Hz
-10 dB at 30 Hz
-18 dB at 20 Hz

C4/SC4:
23.6 liters @ 30 Hz
-3 dB at 58 Hz
-6 dB at 41 Hz
-10 dB at 31 Hz
-18 dB at 21 Hz

QB3:
21.43 liters @ 40.47 Hz
-3 dB at 49.24 Hz
-6 dB at 41.32 Hz
-10 dB at 34.6 Hz
-18 dB at 25.5 Hz

Sealed alignment (depends on the circumstances I guess, but I wouldn't do it with this one)..

7.07 Qtc
13.55 liters
-3 dB at 78 Hz
-6 dB at 59 Hz
-10 dB at 45 Hz
-18 dB at 27 Hz

Is there any way possible that you could simply find a way to reduce the volume of the space inside the enclosure? If so, just try sticking something small and solid in there, but not too big. Line the walls with acoustic damping material, but don't get it in the way of the port. Put it back together and listen, and see if there's any change for the better. If there is, and you like the way it's going, try experimenting with decreasing volume from the cabinet as you did before, until you like what you hear. Then, you could try to do something a little more permanent inside the cabinet if you felt you needed or wanted to. Anyway, that's what I'd try first. Goodluck..

[hpolkerman]

The tuning of the port is 35Hz, and the volume of the enclosure is about 40Liter.

the speaker has a range of 20-22.000 -8db.

[BHTX]

Anechoically, with 40 liters at 35 Hz, response should be about 30 Hz at -8 dB, and 20 Hz at -21 dB. That tuning is almost like an EBS alignment that's too high with a woofer that won't work well for it in a normal listening room. Anechoic response is nearly flat at -1.5 dB without any roll off from 40-70Hz before it falls off too quickly. The added room gain is probably causing the bass in that region to sound boomy, muddy, or over emphasized. With that said, the volume of these enclosures needs to be cut nearly in half. Whether or not you're willing to build new cabinets is, of course, completely up to you. As previously mentioned, line the walls with acoustic dampening material, and rather than sticking small solid objects in the cabinet like I said a minute ago...tossing some big books in there, or something similar, would probably be more beneficial.

[hpolkerman]

The room size is about 7x5meters and the speakers cannot be farther away from the wall then 50cm(23inch).

Sound I build the BR on the baffle or at the back? The port is now on the baffle.

[BHTX]

Jeez, my room is small, only 4.2-4.5 meters deep by 3.6-3.8 meters wide, and I put speakers on the short wall at the front of the room over 1 meter away from the wall, sitting about 2/3 the length of the room, lol. Anyway, a lot of people prefer having the port on the back or bottom of the enclosure if at all possible. In your circumstances, that might boost room gain a bit, which is something you may or may not want if you rebuild the enclosures. If you absolutely can't move them any farther out, I'd probably just put it on the front near the bottom. It's really just personal preference though.

[AKN]

Originally posted by hpolkerman
The tuning of the port is 35Hz, and the volume of the enclosure is about 40Liter.

the speaker has a range of 20-22.000 -8db.

Hi,

I agree with BTHX, try a half size box while first keeping the 35Hz tuning. An alternative would be to just lower the tuning.
Have you tried to block the port, effectively making a really low Q closed box, results?

[Conrad Hoffman]

IMO, that driver/box combo can't be described as "well suited" for much. The box is way too big and even with optimum box and alignment, the LF response is pretty limited, about -3dB at 49Hz. Sealed requires an even smaller box, and the response is rolling off well into the area where it affects male vocals. Two somewhat different thoughts- team it up with a real woofer and call it the mid-bass it really is, or put it in a sealed box to avoid the boom, then (if you have the power) get one of the inexpensive and very good Marchand LF compensator/equalizer kits or pcb to fix the response.

[hpolkerman]

I've tried closing the port, but with a volume of 40Liter it just sounds awfull.

I have the filters all made up allready, so an extra low/sub wouldn't be my first choice. The QB3, 21.43 liters @ 40.47 Hz, option would be the best.

Can I put wool dampening in the port to reduce the speed, or would I only increase the volume/length of the port, so a wrong tuning would result?