[Hearhead]

Hi Guys!

Any ideas on Value For Money 10" Dual Woofers for Open Baffle use?

Plan to make a OB with an 8" Full Range driver (Fostex or MarkAudio) and cross it to dual 10" woofers at the 200hz mark using a minidsp.

Since I can make corrective EQ and Phase adjustments via the minidsp, are there any cheap 10" woofers that can reach 40hz with this setup without any anomalous things happening to the driver?

Room is small (10ft x 30ft and I can only use the far end which is has an area of 8-10sq ft) so I'll probably listen nearfield.

Wiring tips much appreciated (parallel or series dual woofers)

Thanks in advance!

Thanks!

[AJinFLA]

Any ideas on Value For Money 10" Dual Woofers for Open Baffle use?

Plan to make a OB with an 8" Full Range driver (Fostex or MarkAudio) and cross it to dual 10" woofers at the 200hz mark using a minidsp.

Since I can make corrective EQ and Phase adjustments via the minidsp..

...then your only driver concern should be clean displacement and motional noise (chuffing, suspension, etc) vs $$
You really need to provide a specific $ number. An example at the very bottom would be these https://www.parts-express.com/grs-10sw-4-10-poly-cone-subwoofer-4-ohm--292-482.
The pole vent is a bit small but a pair in series is an easy amp load and the 8.5mm xmax might be sufficient unless you need fairly high SPL.
As budget increases, so do choices.

cheers,

AJ

[JLM]

With a 10ft x 8ft room you will be listening near-field!  That's just a walk-in closet around here (not trying to be snotty).  Ceiling height not mentioned but if 8ft, echo at 140 Hz will be a problem unless at least one side wall, floor, or ceiling is well treated. 

Frankly OB is a very poor choice for a room that small.  Note that OB is recommended to have 5ft clear behind and at least 10ft to listening position (shouldn't be against the back wall), so a 25ft deep room is indicated.  And keep in mind that the baffles would take up roughy half the room width, so in effect you'd be approaching a condition of having infinite baffles.  So a minimum ideal room would be closer to 8ft x 14ft x 20ft.

I'd suggest JBL LSR305 (smaller 2-way active monitors, $200/pair on the street) that are designed for stand or desk mounting and have an F3 of 41 Hz.  I had a pair here for a week of listening and liked them.  Just connect to a preamp via $15 XLR cables from BlueJean Cable or Monoprice.

[Hearhead]

With a 10ft x 8ft room you will be listening near-field!  That's just a walk-in closet around here (not trying to be snotty).  Ceiling height not mentioned but if 8ft, echo at 140 Hz will be a problem unless at least one side wall, floor, or ceiling is well treated. 

Frankly OB is a very poor choice for a room that small.  Note that OB is recommended to have 5ft clear behind and at least 10ft to listening position (shouldn't be against the back wall), so a 25ft deep room is indicated.  And keep in mind that the baffles would take up roughy half the room width, so in effect you'd be approaching a condition of having infinite baffles.  So a minimum ideal room would be closer to 8ft x 14ft x 20ft.

I'd suggest JBL LSR305 (smaller 2-way active monitors, $200/pair on the street) that are designed for stand or desk mounting and have an F3 of 41 Hz.  I had a pair here for a week of listening and liked them.  Just connect to a preamp via $15 XLR cables from BlueJean Cable or Monoprice.

Apologies perhaps I wasn't clear in my post (i'll edit it). 10ft x 8ft is the assigned space by my wife in our living room (which is around 30ft x 10ft)

[AJinFLA]

Note that OB is recommended to have 5ft clear behind and at least 10ft to listening position (shouldn't be against the back wall), so a 25ft deep room is indicated.

By whom, on what scientific basis for those objective numbers?

[happyrabbit]

A starting point... I have owned a couple ob designs.  I am looking for a better paper on this subject.  Will forward if I find one.   This pdf is a bit much so read between the lines . 

http://faculty.tru.ca/rtaylor/publications/reflectgeometry.pdf

Dwight. 

[AJinFLA]

http://faculty.tru.ca/rtaylor/publications/reflectgeometry.pdf

Dwight.

Quick read but seems fine. The only real "rule" with an open baffle/quasi dipole, is maintain 1m from front wall. That's it. Even that is flexible given that some OB's are highly forward directional over a wide swath of their responses (large coax cough cough).
Seating distance away from, will be dictated by room and driver summation near/far field. With a fullrange or coax, you can sit right up close with zero issues. That has nothing to do with OB, any more than distance behind seat to rear wall.
It's clear many folks don't understand that monopolar "box" speakers also radiate a significant amount of energy to the side...and rear. Anyone who understands basic physics of driver/baffle propagation/performs measurements knows this.
For a wide ranged dipolar OB, 1m from front wall and party on.

cheers,

AJ

[gregfisk]

With a 10ft x 8ft room you will be listening near-field!  That's just a walk-in closet around here (not trying to be snotty).  Ceiling height not mentioned but if 8ft, echo at 140 Hz will be a problem unless at least one side wall, floor, or ceiling is well treated. 

Frankly OB is a very poor choice for a room that small.  Note that OB is recommended to have 5ft clear behind and at least 10ft to listening position (shouldn't be against the back wall), so a 25ft deep room is indicated.  And keep in mind that the baffles would take up roughy half the room width, so in effect you'd be approaching a condition of having infinite baffles.  So a minimum ideal room would be closer to 8ft x 14ft x 20ft.

I'd suggest JBL LSR305 (smaller 2-way active monitors, $200/pair on the street) that are designed for stand or desk mounting and have an F3 of 41 Hz.  I had a pair here for a week of listening and liked them.  Just connect to a preamp via $15 XLR cables from BlueJean Cable or Monoprice.

I don't know where you came up with 5' from the front wall but everything I have ever read states 3' and OB works just fine for near field.

The OP didn't ask what type of speakers he should use in his room, he asked which speakers he could use in his OB application.

Hearhead, sorry I can't help you with which drivers to use, I'm sure AJ can give you some ideas.

[Hearhead]

...then your only driver concern should be clean displacement and motional noise (chuffing, suspension, etc) vs $$
You really need to provide a specific $ number. An example at the very bottom would be these https://www.parts-express.com/grs-10sw-4-10-poly-cone-subwoofer-4-ohm--292-482.
The pole vent is a bit small but a pair in series is an easy amp load and the 8.5mm xmax might be sufficient unless you need fairly high SPL.
As budget increases, so do choices.

cheers,

AJ

I can spend around 300$ for the 4 drivers but if its worth the extra $$ I can go up a bit.
Thanks!

[JeffB]

Dayton Audio DC-250-8 10" classic woofer.
https://www.parts-express.com/dayton-audio-dc250-8-10-classic-woofer--295-315

[AJinFLA]

I can spend around 300$ for the 4 drivers but if its worth the extra $$ I can go up a bit.
Thanks!

What amplifier and how loud/low desired? The GRS subs linked are mid Q, fairly sensitive and 4 ohm so, can be series wired and driven by just about anything.

[Hearhead]

What amplifier and how loud/low desired? The GRS subs linked are mid Q, fairly sensitive and 4 ohm so, can be series wired and driven by just about anything.

Thinking of buying two plate amps for this (got a passive pre and an SET tube amplifier at 18watts for the full range mids) eq and crossover to be handled by dsp.

I can be happy at an average loudness of 85db

If the grs subs are really on the money for this setup i can allocate some of the funds for an amp so Im open to any suggestions that can handle the low end pretty well.

Are the GRS subs articulate if I cross them at 200-300hz and aim for them to reach flat to at least 40to45hz?

Thanks a lot.

Youre a lot of help.

[Hearhead]

With a 10ft x 8ft room you will be listening near-field!  That's just a walk-in closet around here (not trying to be snotty).  Ceiling height not mentioned but if 8ft, echo at 140 Hz will be a problem unless at least one side wall, floor, or ceiling is well treated. 

Frankly OB is a very poor choice for a room that small.  Note that OB is recommended to have 5ft clear behind and at least 10ft to listening position (shouldn't be against the back wall), so a 25ft deep room is indicated.  And keep in mind that the baffles would take up roughy half the room width, so in effect you'd be approaching a condition of having infinite baffles.  So a minimum ideal room would be closer to 8ft x 14ft x 20ft.

I'd suggest JBL LSR305 (smaller 2-way active monitors, $200/pair on the street) that are designed for stand or desk mounting and have an F3 of 41 Hz.  I had a pair here for a week of listening and liked them.  Just connect to a preamp via $15 XLR cables from BlueJean Cable or Monoprice.

You’re not being snotty but you’re being SNOBBY.

Some people dont have the luxury of space due to budget constraints and their station in life but that doesnt mean they cant try out some sweet OBs....

Ive already got active speakers Yamaha Hs8s and a Kef LS50 I understand where youre coming from but I just want to try out an Open Baffle build with my Dad.

[JohnR]

If you can go to 12" there are some JBLs referenced in another thread here, they seem to go for $40-50 each.

[gregfisk]

hearhead,

you're not going to have any issues with OB in your room. I own a pair and while I do have a large room I have played with them a lot so know what they can do. I've also heard them in a bedroom that was about 8'x10'. Near field sounds really good with OB as long as you can keep them off of the wall. Another false statement you were given is the distance you need to be from the speakers. 10' is NOT the minimal listening distance although it does sound good that way.

As long as you can keep your speakers 3' from the front wall and give them some room in front of them nothing else is going to make them sound bad. I can sit 5' from my speakers and they sound great!

You won't always get good advice here so getting info. from as many people as possible is always a good idea.

Good luck and enjoy your build!

Greg

[Hearhead]

hearhead,

you're not going to have any issues with OB in your room. I own a pair and while I do have a large room I have played with them a lot so know what they can do. I've also heard them in a bedroom that was about 8'x10'. Near field sounds really good with OB as long as you can keep them off of the wall. Another false statement you were given is the distance you need to be from the speakers. 10' is NOT the minimal listening distance although it does sound good that way.

As long as you can keep your speakers 3' from the front wall and give them some room in front of them nothing else is going to make them sound bad. I can sit 5' from my speakers and they sound great!

You won't always get good advice here so getting info. from as many people as possible is always a good idea.

Good luck and enjoy your build!

Greg

Thanks! Glad to hear this!

[roscoe65]

With a 10ft x 8ft room you will be listening near-field!  That's just a walk-in closet around here (not trying to be snotty).  Ceiling height not mentioned but if 8ft, echo at 140 Hz will be a problem unless at least one side wall, floor, or ceiling is well treated. 

Frankly OB is a very poor choice for a room that small.  Note that OB is recommended to have 5ft clear behind and at least 10ft to listening position (shouldn't be against the back wall), so a 25ft deep room is indicated.  And keep in mind that the baffles would take up roughy half the room width, so in effect you'd be approaching a condition of having infinite baffles.  So a minimum ideal room would be closer to 8ft x 14ft x 20ft.

I'd suggest JBL LSR305 (smaller 2-way active monitors, $200/pair on the street) that are designed for stand or desk mounting and have an F3 of 41 Hz.  I had a pair here for a week of listening and liked them.  Just connect to a preamp via $15 XLR cables from BlueJean Cable or Monoprice.

Worth all respect JLM that sounds like a load of hooey.  There are a lot of people running OB speakers with great success in smaller rooms.  For most of us, the only spaces in our houses that run 14ft x 20ft or more are living rooms, basements, or master bedrooms.  Basements typically have ceilings that are less than 8ft, and the other two spaces are unlikely to be dedicated solely to audio use in most households.

You also speak to the need to treat a smaller room.  That goes without saying for speakers of any type.  If we had an infinitely large room (i.e., no boundaries) we would have no need nor ability to treat the room.  As the room gets smaller than infinite in size, our need to treat the room increases significantly unless we have a magically proportioned room.  OB speakers may add a level of compexity to this treatment, but are not a completely different animal.  Over on the acoustics circle there are a number users with OB speakers using very small rooms.  Some will admit that a larger space works better for them, but still got great sound from a pair of OB’s.

Taken to the extreme, if we we start with an infinitely large room (no boundaries) and start to shrink the space, we eventually get a “room” the size of a loudspeaker.  Over on another forum, Joe Roberts discusses options for treating the inside of a 4 cubic foot cabinet of a WE728 speaker.  He discusses this in terms precisely the way we discuss room treatment.  Particular emphasis is placed on controlled reflections rom the back of the cabinet through the cone (analogous to the front wall of our room) and avoiding deadening the cabinet by only damping one wall on each plane (e.g., bottom, right side, back).  These are precisely our concerns when treating a room, particularly with OB speakers.  We need to tame room modes when we can and tame reflections coming off the front wall without killing the liveliness of the room.  One interesting factor is that Joe and others are finding that a rigid absorptive panel in the free space of the cabinet is very effective without deadening the sound.  This has been done by WE and Altec since the 1940’s at least.  If we extend that practice to our room, we should think about some free space absorptive materials in the room (maybe moveable).

While his setup is not OB, the OP should check out GUF’s setup.  He uses one end of a larger space for his listening space, he listens in near field, and he has a god combination of wall-mounted and freestanding treatments that he has found effective.  His space is also aesthetically pleasing (at least to me, but he and I have a lot of overlap in our equipment choices).

[Hearhead]

Thanks for all that info @roscoe65

[gab]

Over on another forum, Joe Roberts discusses options for treating the inside of a 4 cubic foot cabinet of a WE728 speaker.  He discusses this in terms precisely the way we discuss room treatment.  Particular emphasis is placed on controlled reflections rom the back of the cabinet through the cone (analogous to the front wall of our room) and avoiding deadening the cabinet by only damping one wall on each plane (e.g., bottom, right side, back).  These are precisely our concerns when treating a room, particularly with OB speakers.  We need to tame room modes when we can and tame reflections coming off the front wall without killing the liveliness of the room.  One interesting factor is that Joe and others are finding that a rigid absorptive panel in the free space of the cabinet is very effective without deadening the sound.  This has been done by WE and Altec since the 1940’s at least.  If we extend that practice to our room, we should think about some free space absorptive materials in the room (maybe moveable).

Link?

[roscoe65]

Link?

No direct link, but look at the Altec two way threads in Hifihaven High Efficiency Forum, as well as a couple in Audiokarma, etc.  Joe almost always posts under the handle J-Rob or some variation.