[flatfinger]

For accurate I would always say sealed ; It's just so much easier to implement. Reflex is full of stumbling blocks for the designer , and plenty of "perfect compromises" .

 I'll make room for nice honk'in  sealed low Qtc boxes . I have heard some PMC ATL boxes and they did seem to have the advantage of overcoming some of the loudness curves  effects( Fletcher-Munson) ; they were pretty satisfying at low conversational levels ; a very nice trait indeed !!

[*Scotty*]

I have heard accurate bass from vented systems,sealed systems,TLs and aperiodic designs.
The design doesn't determine how accurate the bass is,it is the execution of the design that governs the outcome.
 I prefer to hear what was recorded played back as accurately as possible and that includes the bass portion of the spectrum. 
The key thing I have noticed when listening to instruments that produce bass notes is that the bass doesn't linger in the air. There is no overhang or boomy quality to it.
 This not to say that the performance venue doesn't have a decay time in the bass frequencies that can be quite long.
 Drums heard live always produce a visceral sensation. Drums are felt by the body as much as heard by the ears. 
To properly reproduce pipe organ music the speaker system must be able to pressurize the room
and energize the entire volume of air.
  This is what a pipe organ does to the volume of air in the hall or church it is situated in.
If the speaker system doesn't produce an impact on the body and doesn't energize the air in the room when the recording requires these qualities the speaker isn't as accurate as it could be.
 To put this another way when bass frequencies are produced by percussion instruments it is usually the result of being struck forcefully by the percussionist with a certain amount of controlled violence. If this quality is lost by the loudspeaker when it reproduces percussion instruments it has failed the test in my opinion.
Scotty

[Diamond Dog]

Good post, Scotty. 

D.D.

[SoundGame]

Good post, Scotty. 

D.D.

Agree - great post.  Feeling the music is essential to true reproduction of the live event.  Though this discussion is on bass - the point also ring true for treble.  A hard cymbol hit when hear live can be quite sharp and jarring - I personally like to hear this in a speaker when it's called for.  I hate speakers that are "polite" across the board.

[flatfinger]

 I agree that music should be dynamic of course!

( although  there are times and places where I need some flat , boring , soothing stuff too!)

I wonder just how much transient effect the really low stuff can have ... I mean slap-style bass players have tweeters in there cabs and I have read that any recorded bass that the mixing engineer wants to draw attention too pretty much calls for a boost in the higher overtones of the instrument ....allot of the down low is sort of smushy enveloped stuff sometimes ...

So if I build a sealed  an Identical set of sealed  and use a  Qtc of .707 with one and a Qtc of .6035 or even .5

 ; I  wonder if instruments of their low frequency persuasion are going to have that noticeable of a difference in there transients ( especially if you  high pass below 1 khz for a listen ... )

I'm  sort of curious whether the sub ohmmp that  is in fashion  now......the kind that that flaps yer pant legs  isn't mutually exclusive   from   "realism ".

Just thinking out loud ( dangerous when a noob like me thinks so much !!)

[flatfinger]

uh oh ... I meant low pass @ 1khz  ( where's my edit button )

[rob80b]

Accurate bass, which I get from my Dynaudio Special 25s (bass reflex) with the (Master) Esotar drivers and… the extension with a 15 Velodyne (sealed, always).
But with this set up I do not think of bass as bass as there’s no boom boom or oomph (well there is oomph) but the natural reproduction of instruments that play the lower bass notes and in some instances the extension actual picks up the movement of the actual stage which completes the picture!
I also enjoy the upper bass from my Celestion SL6S (acoustic suspension), and when combined with a good sealed sub hits you in the chest.

[BrysTony]

Accurate bass, which I get from my Dynaudio Special 25s (bass reflex) with the (Master) Esotar drivers and… the extension with a 15 Velodyne (sealed, always).
But with this set up I do not think of bass as bass as there’s no boom boom or oomph (well there is oomph) but the natural reproduction of instruments that play the lower bass notes and in some instances the extension actual picks up the movement of the actual stage which completes the picture!
I also enjoy the upper bass from my Celestion SL6S (acoustic suspension), and when combined with a good sealed sub hits you in the chest.

I have been in the market for speakers for some time and had just about settled on Thiel 2.4s but I have become intrigued by the Dynaco Special 25s.  I have heard Dynaco speakers but will not be able to hear the Special 25.  I had not intended to use a sub so I am wondering how the bass sounds just from the Special 25.  What frequency are you crossing over at for the sub?

Tony

[SoundGame]

I have been in the market for speakers for some time and had just about settled on Thiel 2.4s but I have become intrigued by the Dynaco Special 25s.  I have heard Dynaco speakers but will not be able to hear the Special 25.  I had not intended to use a sub so I am wondering how the bass sounds just from the Special 25.  What frequency are you crossing over at for the sub?

Tony

Hey Tony - I think you meant to say DynAudio rather than DynAco - correct?

[BrysTony]

Hey Tony - I think you meant to say DynAudio rather than DynAco - correct?

Yes, DynAudio 

[SoundGame]

Yes, DynAudio 

Happens to the best of us but just a lot more often to the worst of us....

[rob80b]

I have been in the market for speakers for some time and had just about settled on Thiel 2.4s but I have become intrigued by the Dynaco Special 25s.  I have heard Dynaco speakers but will not be able to hear the Special 25.  I had not intended to use a sub so I am wondering how the bass sounds just from the Special 25.  What frequency are you crossing over at for the sub?

Tony

Hi Tony

Here is a visual generated with the Velodyne SMS-1

Dynaudio 25s Full range/ no sub


25s cutoff at 80hrz crossover/ no sub


25s augmented with Velodyne sub, crossover at 80hrz

Also I've limited the output of the sub to 20hrz although it can go lower.


As you can see the 25s are very respectable in terms of bass output for an 8" driver but I find a sub fully completes the audio spectrum. I’m in the camp that prefers to use a crossover on the mains to increase dynamics and head room by letting the sub do the dirty work and the use of the Velodyne SMS-1 really helps to iron out any peaks and valleys from unwanted room nodes.
The benefits of reducing the bass output of the mains I believe outweigh the negative effect of having more electronics in the chain, the results being less congestion in the midrange producing a better defined sound field especially if you like to listen loud or at realistic levels.
If your listening preference is low to moderate volumes you may find running the mains full range beneficial.

Robert

[BrysTony]

Robert,
Interesting data and comments.  As I understand it, you are running your amp output to the Velodyne sub, equalizing the subs output for your room and feeding everything over 80 hz to the Special 25s.  Is that correct?

Thanks for your input.

Tony

[rob80b]

Robert,
Interesting data and comments.  As I understand it, you are running your amp output to the Velodyne sub, equalizing the subs output for your room and feeding everything over 80 hz to the Special 25s.  Is that correct?

Thanks for your input.

Tony

The output of the BP25P goes to the Velodyne SMS-1 crossover and yes everything above 80hz goes to 4BSST to power the 25s although there is a gradual slope so the 25s are still putting out bass as shown here, everything below to the sub.

Mains crossed over at 80hz no sub.

Room correction is only applied to the sub by the Velodyne SMS-1 with an 180% inversion to stop bass cancellation by putting the sub's bass in phase with the bass that the mains do still produce.

[rob80b]

Always keep in mind crossovers are not a brick wall and both mains and sub will continue to produce frequencies above and below the crossover point, which has always been problematic in getting a seamless transition between the two. Although I've been fairly successful over the last 25 years or so, the introduction of SMS-1 or any device to correct room nodes and the hand off between the mains and sub has been extremely beneficial and has made correctly integrating a sub much easier.

[PRELUDE]

Speaking about TRANSMISSION LINE could be interesting also, but I do not have any long term experiment so I cannot really say any thing.
Based in my experiment in different audio shows in different countries,I think United Kingdom has the most transmisson line speaker lovers and that is why the best ones are made right in UK.
I still would love to hear this one.

Canada is 50% and US might be right here 10%.
Just a thought.

[rob80b]

One more comparison.

To get the best overall response between the sub and the Dynaudio 25 I’ve found that plugging the ports on the mains, which diminishes the duplication of some bass frequencies between the sub and mains, produces better-articulated and tighter bass.

Both frequency responses shown bellow are without the sub engaged.
80hz crossover no plugs


80hz crossover with plugs