About to try and build a great 2way floorstander.

[EdL]

In Martin's MLQW worksheets, one is able to change/adjust the relationships between the volume and dimensions of the casework, the driver and the ends of the cabinet, the driver and the port, the length & diameter of the port and the port position within the cabinet. All of these variables have an effect on quarter-wave resonances within the cabinet. The addition of stuffing and the resultant damping of those resonances can be seen.

Any speaker design is an exercise in trade-offs. The worksheets allow the user to determine what is available from a driver and decide where to make the trade-offs.

It is easy to assume that a MLQW is a reflex box. The careful positioning of elements within a MLQW is easy to miss as well. The results of the effort speak for itself.

I've not seen a reflex design routine that offers so much flexibility or power for optimization. Your comments about the performance of tl's is noted. My experience doesn't support that.

I should add that with some drivers it is necessary to build a large box to find the best one can from a driver. In light of the expressed wishes here, it is possible that a tl would not fit the size requirements.

[Bredin]

This is an article I wrote regarding the application of filter assisted reflex alignments to satellites.

http://sound.westhost.com/qb5align.htm

This is a satellite I have made along these lines.

http://sound.westhost.com/articles/ssl1.htm

The filter assisted alignments differ according to group, group I give the best extension for box size and the filter is around q=2, i.e. 6db. boost, the group II optimize the coupling between the Helmholtz resonator and the driver, this greatly increases the excursion limited power handling and these alignments are very useful for small satellites.

In the quarter wave link note that King himself says that the transmission line acts as a pseudo reflex, I would add it is a complicated overlarge and poorly performing one.
rcw

Yeah, read the earlier post, but I couldn't understand what it said beween all those numbers and formels :M it almost looked like the math test I did today :Z

[Bredin]

In Martin's MLQW worksheets, one is able to change/adjust the relationships between the volume and dimensions of the casework, the driver and the ends of the cabinet, the driver and the port, the length & diameter of the port and the port position within the cabinet. All of these variables have an effect on quarter-wave resonances within the cabinet. The addition of stuffing and the resultant damping of those resonances can be seen.

Any speaker design is an exercise in trade-offs. The worksheets allow the user to determine what is available from a driver and decide where to make the trade-offs.

It is easy to assume that a MLQW is a reflex box. The careful positioning of elements within a MLQW is easy to miss as well. The results of the effort speak for itself.

I've not seen a reflex design routine that offers so much flexibility or power for optimization. Your comments about the performance of tl's is noted. My experience doesn't support that.

I should add that with some drivers it is necessary to build a large box to find the best one can from a driver. In light of the expressed wishes here, it is possible that a tl would not fit the size requirements.

No matter how good my drivers could preform in a TL box of any kind, I think that if I could lower the QTS and get some more accelerationfactor and lower the excursion and than complete the speakers with a subwoofer, would preform better. Bass is easy to ad, midrange isn't :cry: . Something that I didn't think about all to much before I ordered my drivers :Z

[Dennis H]

You're putting a lot of thought, money and effort into the perfect woofer and the perfect box. How about the crossover? It doesn't seem like you have thought about that very much. Do you think that is very important?

[Bredin]

You're putting a lot of thought, money and effort into the perfect woofer and the perfect box. How about the crossover? It doesn't seem like you have thought about that very much. Do you think that is very important?

that was a stupid question :B ofcourse! But the crossover has to wait till I get the woofer the way I want it to. About the filter, I will start with making some different filters with some cheaper components, and after I've decided what layout to go for, I will probably end up with the best mundorf or duelund components in the filter. :T And furutech connectors and probably furutech internal wireing, or chord model better.

[Bredin]

So what do you think? Should I mail AT and ask if it's possible to modify the drivers and than build a SAT&SUB system instead of using my existing drivers in a transmissionline box? I could use my drivers with 0,4 qts in a small enclosure and tune the port high. The biggest problem today with my stereo is that the deepest bass is way to dominant and slow. Built 2 bass absorbents today wich worked very fine on the higher bass and up.
So instead of aiming for the deep bass that I was looking for in the beginning, I've started to think that a speaker who is optimised to play >80Hz and with a subwoofer for the <80Hz tones.
For me it seems obvious today, but I want to hear it from you guys! And AudioTechnology ofcourse( who reopens the 2jan-08)

[rc white]

The small satellite speaker I have given the link to was designed specifically for a 5.1 receiver with a Butterworth 100Hz. high pass on the "small front speaker" setting. This in conjunction with the box tuning gives a qb5II alignment, giving the driver excursion limited power handling down to 100Hz. allowing peak output of 110db. the "hi fi" standard, THX receivers have a lower cut of at 80Hz.

You do not specify your signal source so I don't know if is relavant but using this scheme with a single subwoofer is about the most compact method of getting worthwhile sound.
rcw

[Bredin]

The small satellite speaker I have given the link to was designed specifically for a 5.1 receiver with a Butterworth 100Hz. high pass on the "small front speaker" setting. This in conjunction with the box tuning gives a qb5II alignment, giving the driver excursion limited power handling down to 100Hz. allowing peak output of 110db. the "hi fi" standard, THX receivers have a lower cut of at 80Hz.

You do not specify your signal source so I don't know if is relavant but using this scheme with a single subwoofer is about the most compact method of getting worthwhile sound.
rcw

I have a 2chanel Primare I20 amplifier with pre-out. I don't think I'll need any filter in the bottom if I build a small enclosure instead. 109dB@50hz is possible in a small enclosure, and that will do just fine I think

[Bredin]

I've read that 70-80Hz is the best X-over point mid to bass. And there are many ways to get the driver down to about 80Hz. What do solution do you prefer of Sealed and Vented enclosure? The sealed may give a better impulse response, but the vented works with lower Q and higher acceleration factor and the driver is used as a mid, and thinking of that the driver is X-overed in the lower end, it wouldent be much of a problem with max excursion. So what do you think is the best solution for my driver in this case.
The driver I have today works well to 80Hz in a 11litre box, but it will probably hit it's Xmax and it has a lower acceleration factor.

Any ideas?
Audio Technology opens again 2morrow

[TacoD]

I would go for a closed box. You can get a Q of 0.56, this will match perfectly with a 12 dB filter of a sub.

[Bredin]

I would go for a closed box. You can get a Q of 0.56, this will match perfectly with a 12 dB filter of a sub.

Isn't Q the enemy for a midrange? More excurison = more distortion, lower sound preasure before Xmax, Lower BL = Lower Accelerationfactor,SPL, less control.

[rc white]

reflex satellites

In my article..

http://sound.westhost.com/qb5align.htm

I show that with a cut off around 80Hz. a driver of the size of yours is typically exceeding its linear cone excursion in a sealed box, even at moderate levels. The odd order distortion products this makes are in the upper bass/lower midrange region and are very audible.
The article describes the use of qb5 alignments to greatly increase the excursion limited power handling and reduce distortion, as described in the article it is easily possible to get a 15db. increase in output for the same maximum cone excursion, i.e. the system will play 15db. louder for the same cone excursion caused distortion, at normal listening levels the cone excursion and distortion products are reduced to very low levels.

[Jed]

Bredin,

I just ran the T/S numbers of your woofer in Unibox and it looks like it will work really well in a ported enclosure, so I wouldn't send it back. Bass looks flat down to about 38-40hz in a 20-25L enclosure. You can keep searching for the best but there is no best until you try something and measure it.

My suggestion is to build a small BR tower in about 23-25L tuned to 40hz. Easy to build and great performance.

If you decide to go the subwoofer direction, just seal the port, and you'll get an F3 around 80hz. Perfect for integration to a subwoofer.

Looks like you picked a great woofer to work with now go cut some wood!

[TacoD]

White: interesting read, I want to try that sometime.
Bredin: QB5 makes a nice project .

[Bredin]

Bredin,

I just ran the T/S numbers of your woofer in Unibox and it looks like it will work really well in a ported enclosure, so I wouldn't send it back. Bass looks flat down to about 38-40hz in a 20-25L enclosure. You can keep searching for the best but there is no best until you try something and measure it.

My suggestion is to build a small BR tower in about 23-25L tuned to 40hz. Easy to build and great performance.

If you decide to go the subwoofer direction, just seal the port, and you'll get an F3 around 80hz. Perfect for integration to a subwoofer.

Looks like you picked a great woofer to work with now go cut some wood!

The driver would probably work great in the commercial market. As the small driver deep bass speaker. But thinking of the maximum SPL and distorition and accelerationfactor. The ear is very sensetive when it comes to time, probably more sensetive than the frequency part.

I'm actually worried about the max SPL, speed and distorition of the driver.

[Jed]

What's the xmax? I didn't see it in the TS parameters you listed.

[Bredin]

Maybe it's time to go another way, the 3way!
But I'll start with building a 2way design for my school project.
But after that! there won't be anything like budget or time limits, so I guess that it could turn out fine after some xxx$ and xxx number of days.

I didn't like the RC white idea in the beginning. I'm actually very sceptic against using any kind of filter, but I'm sceptic about fullrange designs to. But now it's starting to get clear. I Will put a Xover in the <80 region on my AT driver and use it in a BR box.

So now, the first thing I will build is a simple 2wayer, and than later we will see if I just complete the speaker with a sub or a 3way filter + bassdriver.

Thanks for all the help!

[Bredin]

What's the xmax? I didn't see it in the TS parameters you listed.

+/- 3.5mm
The max SPL with lower Q in a BR box with a filter in the lower end will be over 109dB. Even if I don't play over 98dB it's still good to know that there is plenty more to give. And I will never push the driver till its max Xmax and the distorition will probably be alot lower than my 0,4 qts driver in a sealed enclosure. High SPL and low distorition is a "pretty" good to have in a "high-end" speaker.

[Bredin]

Recived a mail from AT today. It's possible to send it back and have it recustomized for another aplication.

[Bredin]

So what do you guys think the best solution is? 3way or sat+sub crossed @ 80Hz or 3way crossed >250Hz ?
Thinking of that the ear is as most sensetive to phase around 100-250 makes it feels dumb to XO in that area. The 80Hz solution would probaly have a cleaner lower midrange, but the 250Hz would give more dynamic and clearer top, and it would push max SPL to 120dB instead of 110.

[EdL]

I think the 80 hz solution will be the "best". There is more than I could ever relate to you on this thread: Particularly the things you must do to get head room to 120 dB

http://www.diyaudio.com/forums/showthread.php?s=&threadid=100392&perpage=20&pagenumber=1

[Bredin]

I think the 80 hz solution will be the "best". There is more than I could ever relate to you on this thread: Particularly the things you must do to get head room to 120 dB

http://www.diyaudio.com/forums/showt...0&pagenumber=1

I also almsot think the 80Hz solution will be the best to, so I can use a sidefireing woofer later.

And sure, the VC will be like a lump of alu @ 120dB .

[kevmurray]

In my article..
<snip>
... as described in the article it is easily possible to get a 15db. increase in output for the same maximum cone excursion, i.e. the system will play 15db. louder for the same cone excursion caused distortion, at normal listening levels the cone excursion and distortion products are reduced to very low levels.

I just read your article and found it very interesting. 15dB is impressive! Have you ever had the chance to listen to the same driver in both a QB5 alignment and conventional vented enclosure? I'm wondering if the transient response is noticeably different.

[rc white]

I along with several others have heard systems with the same driver in both sealed and fourth order reflex boxes and the only comments i have had is that the filter assisted sort sounds a lot less edgy and strained if you turn up the volume a bit.
Note that with a sealed box the system will be fourth order with the same filter and the difference in group delay between this and the overall sixth order characteristic with the reflex box whilst measurable has never been demonstrated to be audible.
In fact the satellite plus 80-100Hz. crossover sub woofer system has considerably better group delay characteristics in the audible Blauert and Laws band than a typical three way since it has a much lower crossover frequency.
rcw

[Bredin]

This project is dead.
But the drivers are still alive, and the CQ15h52 got some new specs! And is now designed for a 8.8litre bassreflex box.
Here are some pictures http://www.hififorum.nu/forum/topic.asp?TOPIC_ID=66632
(In swedish, but there is nothing important to read yet, it something important pops up, I'll write it here later)

[Jed]

All that "thinking" and now it's dead? What happened?

[Bredin]

All that "thinking" and now it's dead? What happened?

The transmissionline idea is dead. And 3way is dead.
But a high-end 2way bookshelf speaker is very much alive. The box will probaly be done by next week

[Jed]

Post some pics. :T

When you get a chance.

[Bredin]

Post some pics. :T

When you get a chance.

Check the link in the last post on page 2