Barefoot, what speaker would you Soffit?/ Also, decoupling?

dbluefield · Post by **dbluefield** » Thu Oct 16, 2003 11:43 am

Hi Thomas,

1.) As I get closer to roughing out my soffits, I'm having difficulty finding suitable speakers to put in them.

My available space is roughly 22H x 25W x 15D.

I noticed that John mentioned the JLB LSR 28P in a thread or two, but they are apparently rear ported. The Tannoys that are soffitable are too large. I know you are working on some designs, but are there any canidates you would consider that don't require your filter design that are in current production? Bookshelf speakers? Actice over passive? I have a Hafler PRO 2400 that I could use for passives or for another set of nearfields.

2.) Would putting speakers on a massive stand, say of concrete blocks "floated" on neoprene, be another method for decoupling from the studio side wall? As well as the outer walls?

Since I have not built a room within a room -- if I build the inner speaker support to the outside walls (mostly brick) it seems that I still risk the speakers coupling to the walls/ceiling and sound transmission will cause problems, even if the support structure does not touch the frame of the studio side?

Any help appreciated.

Best,

Dave

barefoot · Post by **barefoot** » Fri Oct 24, 2003 4:44 am

Dave,

Sorry for the late reply. I've been rather busy these days..... in a good way.

Beside my own monitors, Genelecs are the only ones I know of that make specific EQ provisions for soffit mounting nearfields. They are also front ported, so they should work nicely. LDQ just posted some very cool response data for his 1032As that specifically relates to this subject. http://johnlsayers.com/phpBB2/viewtopic.php?t=869

So, you're basically decoupling the speakers from both the inner and outer walls with your concrete block idea, right? Yeah, this is great. You could use any reasonably heavy stand, but concrete blocks are nice and cheap. Yes, I like it!

Thomas

dbluefield · Post by **dbluefield** » Fri Oct 24, 2003 5:12 am

Thomas,

Thanx for the reply.

Any word on when your speakers might be available? I listened to the Genelec 30A's and I thought they sounded nice. People seem to say too nice, whatever that means.

Have any opinions on these babies?:

http://www.abluesky.com/p/p3s1.html

It's a pretty darn affordable 5.1 setup. Plus it has a bass management controller that doubles as a surround monitoring controller? Here:

http://www.abluesky.com/p/p3s3.html

Your thoughts are most welcome

*************

Here's a refinement to my cinder block concept, good?

I'm thinking that as long as I'm re-building my front wall for soffits, it might be worthwhile to frame in a center speaker space anyhow. Why not? I think if nothing else it could be fun to hear some surround, even if it is not ultimately pratical to mix surround due to my space issues. Perhaps the area arround the center speaker would be more absorbant than reflective like the slots I am considering there.

I could fix the rear channel speakers with omni mounts on my left wall and on my right door (that leads to the main room). I measured the 110 degrees yesterday and it would work.

I think a flexible soffit mount de-coupled to all walls would be preferable.

One idea I'm kicking around is an adjustable speaker mount like the omni mounts bolted to my brick wall, and build the studio/soffit wall around them. The omni mount handles the monitor angle positioning, but it does not incorporate vertical and horizontal flexibility. Maybe bolting an omni mount to an adjustable pipe set-up that could slide forward/backwards and up and down, bolted into my brick wall. Maybe I can rig something up with plumbing fixtures. What do you think?

Or OTOH get/build some adjustable floor stands and build my soffit wall around that? In general, I like these ideas better, and I think it would also allow sufficient air flow and heat dissipation -- allowing me to use active speakers. I would still have room to put in 703 and hanger panels below the speakers (though less room if I use stands), but it would not be a tremendous heat trap like putting them in a specifically designed monitor box.

It seems to make intuitive sense to me to decouple the monitors from the studio side wall/baffle/bezel as much as possible. Wall mounting to the brick would, however, still allow a transmission path I suppose from speaker to brick. Think this would be a huge problem?

Floor stands, however, could solve this problem? --probably be spiked or floated on neoprene. As I mentioned in the other post, building a seperate frame behind the studio wall to supposrt the monitors leaves a transmission path (for my room) from frame to brick outer wall. Perplexing.

BUT I just had this idea: How about if the cinder blocks were mortared together, filled with cement, resting on a neoprene or whatever pad. To the cinder blocks I attach two vertical pipes with a vertically adjustable plate. To the plate I bolt an omni mount. The entire thing can then be scooted along the floor for front to aft positioning, and slid up and down the pipes for vertical positioning, and finally angled down to the mix position with the omni-mount. Then, after playing with positioning for a while and putting in absorption and hangers around the stands, I build the studio wall in front of that with a large removable heavy/solid bezels. I would leave a gap at the bottom for bass entry and a small vent at top for air flow (like John's drawing). This would allow one to change speakers, scoot the stand and make fine angle adjustments with the omni stand. What do you think?

Thanx,

Dave

Post by **John Sayers** » Sat Oct 25, 2003 11:41 am

Dave - Event 20/20s, Mackies, KRKs and Roland Digital DS90A's have all been successfully soffit mounted by guys at the Construction site. That's quite a range to choose from. I've also successfully soffit mounted Tannoy little reds, JBL 4311s and 4350s and Yamaha NS1000s.

cheers
john

dbluefield · Post by **dbluefield** » Sun Oct 26, 2003 1:15 am

Thanx John,

I went ahead and picked up a pair of Dynaudio BM15's yesterday.

I listened to them for 3 hours next to the Blue Sky's, Genelec 1030's (both with/without subs), and I auditioned some Quested 2108s.

For those interested, I found the Genelecs made everything sound awesome, even stuff which I knew was very harsh in the midrange. I think one might be disappointed listening to mixes on speakers other than these. If the whole world was listening to Genelecs, no problem. They would make great home theatre speakers IMO, and I mean that in a good way.

I didn't like the Blue Sky's at all. Kinda TIN-ish in the mids and tubby in the low, especially with their sub. I really wanted to like theses speakers as they offered a very valuable package on paper. But unfortunately, I didn’t like what I was hearing.

The Quested sounded very neutral and very good, but one of the woofers gave out, so that and their sticker price brought them out of the running.

To my ears the Dynaudios sounded just as neutral as the Quested, with perhaps a little more in the highs. They have a HF and LF trim +(-) 3db which should allow some room for adjustment for soffiting. They are front ported. I know some people, in particular Thomas, have mentioned they do not like the mid range performance in a larger than 6.5 inch woofer, but that is not what I heard in the Dynaudios. Nonetheless I will keep my M1's with my hafler for additional monitoring, as well as try some Tannoy reveal passives with the Hafler in the future.

So many speakers are rear ported that this took many out of the running for Soffiting. I am going with Thomas' suggestion not to use rear ported speakers in a baffled front wall. The Dynaudio AIR system looks great on paper (fully adjustable bass management in a digitally controlled speaker from the mix position, capable of fine speaker tuning) but they are all unfortunately all rear ported.

I am also going to soffit the Dynaudios using some form of Thomas' (Barefoot's) decoupled method. Most likely with stands that to not touch the front Baffle/Bezel, with as much bass trapping and 703 I can fit in there. I think there will be no major heat issues with these active speakers on a stand or shelf, and I am still debating whether or not to allow a bass port in the bottom of the wall, and a vet in the top. Any comments Thomas? It is my understanding that a baffle with no openings is preferable.

Thanks for all the input guys; I will keep anyone who is interested posted on the results, as well as do some freq response analysis when I finish the control room.

Best,

Dave Blauvelt

barefoot · Post by **barefoot** » Tue Oct 28, 2003 5:09 am

Dave,

Openings in the corners above and below the speakers are fine - as long as they are at least a few feet (1m) away from the speakers. John's method of covering the wall panel below the speaker with a thin absorbent layer to reduce mixing board reflections is also a good idea - as long as the material does not have much absorption below about 1 kHz. In both cases the broadband hemispherical radiation pattern will be maintained.

I see you didn't care much for the Blue Skys..... "Kinda TIN-ish in the mids". I have to agree. Metal cones have very sharp resonances. For a 6.5" driver these resoances typically start about 5kHz and spike up 10dB or more above the nominal pass band output level. These resonances are MUCH to close to the pass band to be affectively attenuated. Notice that the Blue Skys use a 1.5kHz crossover to try minimize this problem. However, even this low crossover frequency isn't low enough to be effective - not to mention it puts undue strain (distortion) on the tweeter.

When properly implemented metal cones can be truly outstanding. In the case of my MiniMain12 I use an aluminum cone sub driver. It provides near perfect piston behavior in its pass band. It also has very sharp resonances starting at about 1.5kHz. These can't be avoided. However, these are almost 4 octaves above the pass band. Using the crossover and extra filtering I push these resonances more than -95dB below the nominal output level. This would be impossible to achieve with the Blue Sky arrangement unless they used a brick wall filter that would also then ring like a bell. With the current state of the technology I would not consider using a metal cone for a midbass driver. It's no surprise you didn't like them.

And congratulations on your new Dynaudios! I still think a good 5" midbass will easily out perform them in the midrange, but without question the Dyns are hard to beat when compared to the average monitor!:)

Thomas

dbluefield · Post by **dbluefield** » Tue Oct 28, 2003 6:47 am

And congratulations on your new Dynaudios! I still think a good 5" midbass will easily out perform them in the midrange, but without question the Dyns are hard to beat when compared to the average monitor!

Thanx Thomas. I listened to them all weekend while working on my rear wall. I like them allot. I also flipped them upside down -- which put the tweeter right at ear level, just above the meter bridge on my temporary cinder block stands. I immediately noticed better imaging/clarity -- most likely due to reduced console reflections. Any detrement to doing this? It would make soffiting much easier as there would be no need for angling the tweeters down.

I agree that some 5" speakers might make for a useful combination with the Dyns. You working on some of those too?

What I particularily like about the BM15's is the reasonable picture of what's happening in the lows without sounding boomy -- like the Mackie 824s etc. ; even without a sub (though I can get one down the road if I so desire); I listened to some very well recorded CD's with fabulous low end mixing/imaging and they are truly a pleasure to listen to, while also accurate enough in all frequencies (IMO) to do good work.

I put a friends recording on-- there was stuff they obviously could not hear in the low end that was muddying up everything else -- most likely mixed in a room that made them want to add more bass, not realizing that they were taking up allot of headroom with very low freqs.

Thank you for all of your valuable insights. Hopefully I will get to the soffits in the next few weeks and can post some pics of my treatments and soffits for anyone interested.

Best,

Dave Blauvelt

bluesky · Post by **bluesky** » Sat Nov 01, 2003 5:14 am

barefoot wrote:Dave,

Openings in the corners above and below the speakers are fine - as long as they are at least a few feet (1m) away from the speakers. John's method of covering the wall panel below the speaker with a thin absorbent layer to reduce mixing board reflections is also a good idea - as long as the material does not have much absorption below about 1 kHz. In both cases the broadband hemispherical radiation pattern will be maintained.

I see you didn't care much for the Blue Skys..... "Kinda TIN-ish in the mids". I have to agree. Metal cones have very sharp resonances. For a 6.5" driver these resoances typically start about 5kHz and spike up 10dB or more above the nominal pass band output level. These resonances are MUCH to close to the pass band to be affectively attenuated. Notice that the Blue Skys use a 1.5kHz crossover to try minimize this problem. However, even this low crossover frequency isn't low enough to be effective - not to mention it puts undue strain (distortion) on the tweeter.

When properly implemented metal cones can be truly outstanding. In the case of my MiniMain12 I use an aluminum cone sub driver. It provides near perfect piston behavior in its pass band. It also has very sharp resonances starting at about 1.5kHz. These can't be avoided. However, these are almost 4 octaves above the pass band. Using the crossover and extra filtering I push these resonances more than -95dB below the nominal output level. This would be impossible to achieve with the Blue Sky arrangement unless they used a brick wall filter that would also then ring like a bell. With the current state of the technology I would not consider using a metal cone for a midbass driver. It's no surprise you didn't like them.

And congratulations on your new Dynaudios! I still think a good 5" midbass will easily out perform them in the midrange, but without question the Dyns are hard to beat when compared to the average monitor!:)

Thomas

Hello All:

My first post here and I hope that you guys don't mind me posting here.

I just wanted to be clear, with regard to our 6.5" driver, it isn't a metal cone (as with our 12" driver). It is made out of mica filled polypropylene and is very rigged, but doesn't ring like an untreated metal cone driver. We do have a 5" MF driver, a 4" MF driver and an 8" LF woofer that are aluminum, but these units have a custom coating on the back and a custom bonding agent for the voice-coil former, to deal with any of the typical problems found with metal cone drivers.

With regard to dbluefield experience with our speakers; I would say that setup, calibration and sub placement are critical to getting the proper performance. Additionally, personal preferences and program material can have an affect. Also, specifically with regard to the SUBs performance, when placed and calibrated correctly, the system should not be boomy, or in anyway tubby and this is a comment we don't get unless the system isn't setup correctly (usually easily addressed). You may be set on not using our speakers, that is OK, we can't win them all, but feel free to contact me and we are more than willing to work with you to do another proper demo in your studio - no cost to you (other than some time).

Let me just end by saying that we have a very high degree of confidence in our product. We have been doing this for a long time, have a large number of high-profile users and the feedback we get from users and reviewers supports my claims.

Anyway, like I said, I hope nobody minds me posting here.

Cheers -

barefoot · Post by **barefoot** » Sat Nov 01, 2003 5:22 am

Dave

I don't see any problem with flipping them upside-down.

Thomas

barefoot · Post by **barefoot** » Sat Nov 01, 2003 5:28 am

Pascal,

Welcome to the forum.

Sorry for my mistaken identification of your 6.5" speaker cones. :oops

Though, I still stick by my general comments regarding metal cone midbass drivers. I'm not familiar with your specific technology, but it's been my experience that the added mass of effective damping materials introduces a whole other set of efficiency and impulse response compromises.... once again leading me away from metal cones.

Anyhow, we all have our preferred approaches and I won't belabor the point if you have found something that works for you.

Regards,
Thomas

bluesky · Post by **bluesky** » Sat Nov 01, 2003 5:42 am

barefoot wrote:Pascal,

Welcome to the forum.

Sorry for my mistaken identification of your 6.5" speaker cones. :oops

Thomas

No problem... They do look like aluminum.

Thank you for the welcome.

Gwen · Post by **Gwen** » Fri Aug 06, 2004 11:18 pm

Hi John,

in this post you mentionned that you successfully soffit mounted Tannoy Reveal passive. One thing that puzzles me about this (I own NS10s and those Tannoys and planned on soffit mounting the Reveals) is how do you handle the rear port in that case ?

Thank you,

Gwen