Bass Reflex Mod For LaScala?

[D-MAN]

If you are using the K33E, I would NOT widen the slot.

If you are using ANYTHING other than a K33E, then the wider slot is generally recommended. Each driver would be most efficient at a specific slot size, but the widest that the horn can do is 6x13". As a general rule, that is the slot size to use for most drivers (beware of any B&C 15" drivers!).

Speaking from my experience with the K33E using the wider slot in a Khorn-sized horn, it sounded like C.R.A.P. It got overly flabby and puffy-sounding. Horrible!

DM

[Rockets]

I have to ask this question since I was looking at Bob Crites K-33's on

eBay. Given that pre 85' K-33's have a Fs of 26hz would they be a good

alternative candidate for the K-43 even though the K-43 has a lower

QTS. I've read multible times in the past the k-43 doesn't sound

as nice as the newer k-33, but on the plus side it will go lower.

If one could split the difference would an old school k-33 do it?

I assume the trade off will be the lower end db output , but how much?

Any other pro's or con's?

Thanks

[DrWho]

The K33 is the stock driver in the lascala so of course it would work []

Btw, the reason for going to the K-43 is because it has more raw

excursion available, which is a necessity for LF reproduction. So the

only tradeoff you're talking here is a few dB in max SPL...the response

curves should however be very similar.

[D-MAN]

I have to ask this question since I was looking at Bob Crites K-33's on eBay. Given that pre 85' K-33's have a Fs of 26hz would they be a good alternative candidate for the K-43 even though the K-43 has a lower QTS. I've read multible times in the past the k-43 doesn't sound as nice as the newer k-33, but on the plus side it will go lower. If one could split the difference would an old school k-33 do it? I assume the trade off will be the lower end db output , but how much?

Any other pro's or con's?

Thanks

First, the K43 DOES NOT GO LOWER - it has a higher FS than the K33.

It DOES handle more power and is less efficient, as you suspected - THAT is the tradeoff...

I would not use the K43 as an alternative to the K33/E for Hi-Fi use except in applications requiring a higher power handling capability.

DM

[djk]

The K43 is more efficient than the K33. It is higher efficiency both as a direct radiator, and as a horn driver.

The Fc of the horn determines the low end for horn loading. A driver with a low Qts can go much lower than its Fs.

Below the Fc of the horn, the driver reverts to a direct radiator. At this point the low Qts driver is at a disadvantage, and that is why 'a K43 will not go as low as a K33'.

[D-MAN]

Dennis is right - I meant "in a horn", not a direct radiator.

Seems that "in a horn" is all I ever talk about!

DM

[DizRotus]

Bump for newbie.

[robster]

I had the TAD-150 hooked up to the Cayin TA-30 for a few weeks,the Cayin was full Bizzy Bee modded. I coudn't kill my ground loop problem and gave up! The Tad-150 w/remote is cool but I was told to trun up the volume up all the way on my Cayin TA-30 to short-out the volume pot,that caused big problems for moi! Gawd awful ground loop noise,especially with high effeciency speakers like the Chorus II's.

Paul at 2baudio.com is wonderful to buy from! Honest,kind and a pleasure to talk to.

I quickly sold the TAD-150 on Audiogon then shortly after the Cayin.

Cheers,

Robert

[markgod]

I shot him an e-mail asking him to post his comments ,so all can benefit from his experience with the Tad 150.

Thanks,

Mark G

[jbsl]

Lar you have the TAD 150 and the TAD 1000 mono blocks do you have any ground loop problems?

Robster do you mean hiss or hum with the TAD 150 and Cayin?

[jbsl]

Someone else had the TAD 150 and Cayin but eventualy sold them for a Redgum integrated tube amp, I think.

Mark have you gone to Audiogon and AudioKarma and done a search or posted for anyone with the TAD 150 and Cayin TA 30?

I have been using a Luxman int amp with my Cayin and the combo is very quiet! No hum and you have to put your ear almost next to the La Scalas to hear any hiss.

I have tried two tube preamps and my Luxman sounds better to me. I was not able to do any tube rolling in the tube preamps so that would have helped.

Just curious but how did this go from a bass bin mod to the review of the TAD 150/ Cayin TA 30 combo?

[markgod]

I just went to Paul G sight and read the reviews he has links to on his sight . There are quite a few other people with the Cayin TA-30 and the tad 1500 that rave about the combo. This ended up here because someone replied to the thread that I started in the 2 channel section and had this thread on there reply[the 3rd post] and when I responded I clicked the wrong response box. Meant to pst on the original 2 channel posting. I just wonder why Robert had problems and others did not.

[DizRotus]

Has anyone not liked the results of this easily reversible mod?

[Marvel]

Neil,

I think very few on here have actually done the mod. As I recall, those who have tried it, liked it.

Pete Fowler posted this earlier:

My buddy Thermio and I both scratch built a set of LS bass cabs and he did the djk mod to them. He took measurements on one cabinet as the mods progressed. Here is the data:

200 160 125 100 80 63 50 40 31 25 20 HZ

77 80 79 73 72 78 68 60 61 52 51 dB Stock, mouth braced

76 78 78 73 69 75 65 60 66 56 52 4.5 cuft, no ports

76 78 77 75 74 80 70 60 68 54 54 Two 4"dia 10" ports

76 79 78 76 75 80 71 60 68 54 53 Ports cut to 7"

The interesting thing with 10" ports is the boxes went deep, but the snappy, fast horn sound was lost! Cutting the port length to 7" brought the snap and speed back to same as stock, plus the lows remained, esp. at the 31Hz box tuning point. This data is with K33E driver and light stuffing. We think a K43E in this box would be superb, but haven't tried it yet.

I'm going to try the mods using two 4" ports with both ends flaired (Thermio used 4" PVC). Flaring is supposed to reduce distortion and possibly increase the gain. Parts Express sells the kits.

Neither of us is going back to stock.

Pete

[solarcarl]

Here's one more for having done the mod. I stuck with the plan that was posted in terms of dimensions. It took one sheept of MDF exactly and four ports that were flared and almost exactly 7" long.Unlike my usual style of A/B ing things I gutted the speakers and swapped out crossovers and horns and so whatever sound I get will be a sum of all the mods together. I can easily pull the bass bins away and slap the stock bottom covers back on for comparison but for the rest there is no turning back. I'd never have done all these crazy things to my speakers if it wasnt for you guys.

I dont know what they sound like yet because I still have to put Als crossover kits together first.

[Marvel]

Did you use any kind of gasket material between the LS and the new bottom?

[solarcarl]

I'll glue some foam tape around the edge of the cutout and just set the speaker on top of the base with no screws. I just got my crossover kits today and its supposed to rain all week so I'll be doing some soldering and tinkering instead of working outside.Carl

[DizRotus]

Please report back when you're done. I'm looking forward to reading about your listening impressions.

[Rotorhead09]

Has anyone done the port mod though the top section?
Closing off the top back half and porting it with 2 4"x7 ports
and opening up the top dog house cover?
I believe Bruce a 3d drawing of this. (also gave me the idea)
Just wondering if it has been done before or just a new idea.

If it has been done what kind of results did they get?


Thanks
S. Lee

[D-MAN]

Frode's custom LS.

DM