Bert's 150 bass filter - Thanks (Oris Horns)

by Tom Russell @, Tuesday, March 13, 2007, 13:48 (3965 days ago)

Bert

I want to thank you for the filter values. That thread went on a bit so I decided to start over here. I've had a chance to do an initial evaluation and I have some results. I made the bass filter using the exact values you gave and the overall system tonal balance is very good. I don't think there is a need to adjust any of the values at this time. There is plenty of bass gain. I turn the linear pot down about 1/8 of a turn and things are about right. The overall gain of the system, however, is noticeably less when compared with using the active filter.

The biggest change I experienced is in the sound quality. As you know, I use a specially built amp to drive the 150s directly. This amp rolls off the lows so I use no filter in the horn signal path. I had been using a Rane active crossover as a low pass filter to drive the bass amps and then the BD Reference cabs. I use an interconnect with a simple Y at the source to supply the horn amp and the bass filter. Before, using the active crossover, I was OK with the bass sound. Mostly, I didn't think much about it much and I thought that was a good thing. It didn't intrude into the mids. It reminded me of a slightly warm sounding LaScala. Now, with no other change but replacing the active filter with the passive filter, the bass is much more dynamic, much more felt. It's the best of both worlds with a bigger, warmer, punchier, lower, nicer sound but there are no problems with bass overages interfering with the lower mids. It is a vast difference and it's all for the better. When I decided to go with the Oris system, I knew the horns would be OK. My main concern was with the bass. I have full range electrostats and they will make one very sensitive to multiple drivers and crossovers. Either on their own or as part of the system, I have no problems with the performance of the Reference cabs. They are far better than I imagined they could be. Thanks!

Even more notable, since the installation of the passive filter the sound coming from the horn is vastly different. I am aware that I have used vastly twice. If anything, calling these changes "vastly different" is conservative. Before the passive filter, the system sound was certainly good but the horn system fell short of the electrostats in resolution, inner detail, soundstaging, imaging - less good on a lot of little things. Now, all of these parameters are essentially commensurate with the stats plus I get the dynamics and the vibrant tonal color of a horn. A very good deal! I'm not sure how the bass filter, located in it's own local circuit, can effect the sound of the horn to such a large extent but it certainly did in this instance. I wouldn't think that the changes I experienced are indicative of active/ passive filter comparisons in general but the changes I experienced are real and quite substantial. Maybe reading this could help someone else at some point. If you're having a problem with the sound but everything seems to be working up to spec and you can't figure it out, don't assume, as I did, that this part here can't possibly be effecting that part there. It ain't necessarily so.

Bert, This is the sound I was after when I decided to go to the trouble of assembling a new system. This is the sound I expected when I went off the beaten path with a specially built amp. This is, on any terms, really, absolutely, first class sound. Thanks again!!


Tom


BTW, there has been some discussion in other threads about the value of amplifiers specially designed to drive horns. Obviously, I think a dedicated amp is the way to go. The advantages of doing this are usually said to be lessening the load on the driver, by not making it handle low frequencies, and not having any device in the signal path that would effect the purity of the audio signal. True on both counts but there is another plus that is just as significant, especially if we are talking about an SET amp. The big SET design problem is the output transformer. If you make it large enough for full range lows, it is sluggish in the highs. If you optimise for the mids and highs, the lows are not so good. Asking an SET to do a full range signal into a speaker load is too much to ask. Most SET amps do the best they can to balance this but they necessarily end up with both soft bass and not much top end bandwidth. If you design an amp so it does not have to deal with the low frequencies, it allows for an optimised design of all the other performance parameters and the bandwidth goes through the roof. It sounds good, too!

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Bert's 150 bass filter - Thanks

by MichaelW @, Tuesday, March 13, 2007, 18:42 (3965 days ago) @ Tom Russell

Hi Tom.
Very interesting.
Back in my mind I´m always thinking about how to use the passive filter instead of my acitve filters.
I´m also using an amp for the Horns, which has a natural rolloff in the bass.
That is why I´m using the active crossover (Hornamp + active crossover behind my preamp with 2*2 Output in a Y-circuit).
I don´t understand how you connected the passive filters.
I thought, behind the hornamp I get the bass-rolloff on the bassspeakers too. Passive filter behind the preamp with Y-circuit won´t work, as Bert told me, cause te filter will work on the line to the horns too. Not to mention the lack in gain.
Could you please tell me your setup with the passive filters ?
Thank you.
Best regards, Michael

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Bert's 150 bass filter - Thanks

by Tom Russell @, Wednesday, March 14, 2007, 03:51 (3965 days ago) @ MichaelW

Hi Tom.
Very interesting.
Back in my mind I´m always thinking about how to use the passive filter
instead of my acitve filters.
I´m also using an amp for the Horns, which has a natural rolloff in the
bass...........Passive filter behind the preamp with Y-circuit won't work,as Bert told me, cause te filter will work on the line to the horns too.
Not to mention the lack in gain.
Could you please tell me your setup with the passive filters ?
Thank you.
Best regards, Michael

Michael

What I have is a simple as can be Y. I normally am a hard wire guy but to facilitate setting up the new system I am temporarily using RCA plugs. I made an interconnect starting with an RCA that plugs into the CD player. There are two + wires attached to this plug, one going to the horn amp and one going to the bass filter, be it active or passive. When I changed from the active to the passive bass filter, I simply unsoldered the wires from the input connector on the active filter input and attached them to the passive filters. The passive filter is simply all of the individual components soldered together and to an RCA plug which goes to the bass amps. As you see, there is no preamp. I particularly selected the Droplet for CDs because it has an analog domain remote volume control.

Regarding the gain, it is just enough. If you want 100db+ levels, it's not there but it does play plenty loud enough so that you'll have to turn it down in order to speak to one another. I could always add a pre-amp and get another easy 20db of gain but electronics are never a sonic free ride. The system REALLY sounds good and I am not interested in changing things now. I'm a lot closer to removing all of the connectors and hard wiring everything. I realize the the phono (for which I don't currently have all of the pieces) could be a problem here but, if I figure it corrrectly, it should have more gain than the CD player does with my transformer, or perhaps a pre-pre, added to the phono stage.

BTW, if anything, I have undervalued the overall sound of this set-up.


Tom

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Bert's 150 bass filter - Thanks

by Rudolf150 @, Wednesday, March 14, 2007, 20:04 (3964 days ago) @ Tom Russell

Hi Tom,

Maybe I missunderstood you here; you were writing that you replaced the active filter with a filter consisting of separate components soldered together; so in both cases the filte is before the bass ampe, right?
I thought when a filter is inbetween the speaker and the power amplifier, then this is called passive. And if the filter is between source/preamp and power amplifier, then this is called active.
Or am I wrong here?

I am just trying understand fully your setup :satisfied:

Thanks,
Rudolf

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Bert's 150 bass filter - Thanks

by Tom Russell @, Wednesday, March 14, 2007, 22:18 (3964 days ago) @ Rudolf150

Hi Tom,

.............I thought when a filter is inbetween the speaker and the power amplifier,> then this is called passive. And if the filter is between source/preamp> and power amplifier, then this is called active.
Or am I wrong here?

I am just trying understand fully your setup :satisfied:

Thanks,
Rudolf

I usually think of passive as not requiring a power source, such as the RC filter network I am currently using on my bass, while active circuits, such as the Rane crossover I previously used, require power and either plug into the mains or have a battery power source. For example, a passive pre-amp has no active circuitry.

I realize that the term passive pre-amp is a misnomer as it doesn't amp anything. I used it as an example both for clarity and to illustrate the loose terminology that is accepted in audio.

Tom

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Bert's 150 bass filter - Thanks

by MichaelW @, Wednesday, March 14, 2007, 21:14 (3964 days ago) @ Tom Russell

Hi Tom.
Thank you for the explanation.
This means your Y-cable is nothing different to my preamp with 2 outputchannels soldered to the output (concerning the interaction between the two sides of the Y).
I never tried, cause Bert told me, the passive bassfilter on the one side of the Y will also filter my hornamp on the other side of the Y if the two outputs are not seperated and just connected "Y".
Probably I missunderstood this.
I will try the passive filter instead of my active ones and see, if it works.

Michael

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Bert's 150 bass filter - Thanks

by Bert @, Tuesday, March 13, 2007, 19:32 (3965 days ago) @ Tom Russell

Hi Tom,

Thanks for the feedback. You did forget to mention that your amplifier was limited in frequency before you connected the passive line-filter and that you've change the input filter of the main amp now?

Or did I mis something?

Ciao,

Bert

--
BD-Design - Only the Best!

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Bert's 150 bass filter - Thanks

by Tom Russell @, Wednesday, March 14, 2007, 04:49 (3965 days ago) @ Bert

Hi Tom,

Thanks for the feedback. You did forget to mention that your amplifier was
limited in frequency before you connected the passive line-filter and that
you've change the input filter of the main amp now?

Or did I mis something?

Ciao,

Bert


Bert

Miss something? Maybe. Reading you reply, I get the same feeling I got when reading past replies you have made to me, that you think I am someone else. Before I obtained any of the parts, this system design has been the same, even down to the brand and model of the individual parts. In your reply concerning the bass filter values, you said you thought I had Altec bass components. When I read this I knew that you were thinking of someone else but I didn't mention it at the time. Last year, when I wrote you about RMAF, I went through my system and mentioned that you might not want to display your stuff with a one off amp as people who heard a system that had a one of a kind amp that uses uber rare tubes would have no basis for any comparison.

At any rate, I am the Tom Russell, of Dallas, Texas, listener of an Oris 150 horn, AER2 drivers, BD Design bass cabs, one of a kind SET amp that rolls off at 150hz, your bass filter, Marantz MA500 bass amps, and Droplet CD player.

I have no input filter on the horn amp.


BTW, your stuff really does sound good.


Thanks

Tom

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Bert's 150 bass filter - Thanks

by Bert @, Wednesday, March 14, 2007, 09:08 (3965 days ago) @ Tom Russell

Hi Tom,

Miss something? Maybe. Reading you reply, I get the same feeling I got
when reading past replies you have made to me, that you think I am someone
else. Before I obtained any of the parts, this system design has been the...

Probably....perhaps this is because I can't put a face (or a system picture) to your name. I think I am mixing you with Tom Lester all the time...:wink:

Sorry about that!

Bert

--
BD-Design - Only the Best!

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Bert's 150 bass filter - Thanks

by Rudolf150 @, Tuesday, March 13, 2007, 22:43 (3965 days ago) @ Tom Russell

Hi Tom,

Many thanks for sharing your experiences; good stuff to read and to think about.

As you can see from my post below, I am stil in a dilemma between a bandpass amp or a full amp for the horns.
I agree (there is nothing to agree actually, it is a fact) with your point about having a dedicated (bandpass) amp for the horns. The bandpass amp I am considering should go to over 200 kHz (starting from 150 Hz). But somehow interactions - as you have written as well - between the components (and room influences, etc.) can change the eventual sound outcome. In my case I will be using a TVC, which will make the loading by 2 full amp more tricky.

I am not a specialist, but if you imagine (in your situation) the loads the preamp is seeing in the 2 setups (I hope I will get it right here) is different, you could maybe explain the different sound in the horns.

Question: between the 2 different setups, did you notice any difference in the dynamics of the bass?

Rudolf

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Bert's 150 bass filter - Thanks

by Tom Russell @, Wednesday, March 14, 2007, 05:00 (3965 days ago) @ Rudolf150

Hi Tom,

Many thanks for sharing your experiences; good stuff to read and to think
about.

As you can see from my post below, I am stil in a dilemma between a
bandpass amp or a full amp for the horns.
I agree (there is nothing to agree actually, it is a fact) with your point
about having a dedicated (bandpass) amp for the horns. The bandpass amp I
am considering should go to over 200 kHz (starting from 150 Hz). But
somehow interactions - as you have written as well - between the
components (and room influences, etc.) can change the eventual sound
outcome. In my case I will be using a TVC, which will make the loading by
2 full amp more tricky.


You are correct. Everything is in the system and everything effects everything. Still, I was very surprised at the extent of the difference only changing the filter made. I think there is a good chance that the active filter had been malfunctioning for a period of time. This all came to bear when the active filter lost one channel and I had to replace it. I have no way of proving this as I don't have another active filter to try. Lookingback, thinking that the filter had been causing errant problems before it gave up completely is currently my only way of rationalizing the extent of the differences I experienced.


I am not a specialist, but if you imagine (in your situation) the loads
the preamp is seeing in the 2 setups (I hope I will get it right here) is
different, you could maybe explain the different sound in the horns.


Probably.

Question: between the 2 different setups, did you notice any difference in
the dynamics of the bass?


Yes, and quite a bit. The bass sound is bigger, better, lower, etc. This is part of the reason I think there is a possibility the active crossover was malfunctioning before it quit. I would usually think that an active set-up would be, if anything, more dynamic in it's presentation than a passive set-up. Not so this time.


Tom

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Bert's 150 bass filter - Thanks

by lucanato @, bari-italy, Tuesday, December 11, 2007, 19:15 (3692 days ago) @ Tom Russell

sorry ,my name is Luca from italy,nice to meet you.
this is my first post.
1)bert how can i open a new post?!?
2)tom,i am next to do a sistem like your's.i have a bass enclosure with altec 416 and a lowther dx3 in dipole over the bass
3)i have to buy everything to go to bi-amp and cut off the passive crossover
4)i think to gainclone for the bass and a 45 direct heated triode amp for the upper frequency
5)i need an active cross over and i thought to behringer,but you tell me that i could insert a passive-line-cross over before the bass amp and that it's better than the active solutione,is it right?where can i find this cross over ?is it usefull also for my altec or only for bd woofers?
6)than i would like to buy an oris horn,and i woul like to know how they improve/modify the sound of the speaker alone.for little rooms 150's it's the same than the 200's?how does the sensivity increase?any graph?can i use a horn in a dipole sistem(horn in the front hanging on a dipole and nothing in the rear))
7)i hope you read this reply.....


thanks a lot
lucanato@yahoo.com

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